XIV ET Symposium | Maastricht

6 May 2024, 09:00 → 10 May 2024, 14:00 Europe/Rome

MECC

Welcome to the XIV ET Symposium

The upcoming ET Symposium will take place in Maastricht from May 6th at noon until May 10th early afternoon. This symposium gives the chance to unite with colleagues deeply engaged in the Einstein Telescope project and those who share a profound interest in ET. Together, we'll delve into recent advancements and exchange insights while forging lasting connections.

The ET-symposium kicks off on Monday, and offers a rich array of parallel sessions (OSB, ISB, EIB, SPB, etc) and poster presentations housed in the MECC conference center until and including Wednesday. As the week progresses, we'll transition to the historic Sint Jans Church in the heart of the Maastricht city center, where plenary sessions will be held on Thursday and Friday.

 

Registrants can also participate in every session online via a two-way Zoom connection. Zoom links for each session can be found as an attachment to the session in the Indico timetable.
 

But, the symposium isn't confined to the timetable of the sessions. We extend a special invitation to join us on May 5, the day prior to the symposium, to explore a scenic geology drilling site of ET (we organize a bus that will leave from Maastricht).
And to kickstart the symposium, join us on the morning of May 6th for a visit to the E-Test project locations in Liege, where the Advanced Mechanical and Optical Systems (AMOS) and the Centre Spatial de Liège (CSL) open their doors (organized bus from Maastricht). 
There is a social event organized specifically for early career scientist on Thursday May 9th. We will meet after the plenary sessions in front of Sint Jans Church and walk towards the river Maas to have a BBQ at Stayokay hostel from 7pm. Register here before Thursday May 2nd and receive your ticket on Thursday before the walk.

There will also be moments where you can experience the ETpathfinder project from the observation lounge, enjoying a panoramic view of an ET test facility cleanroom.

 

Hope to see you at the ET Symposium 2024; register here.

In the meantime, dive into lively conversations with your peers, seek travel advice, coordinate social outings, and share experiences via our dedicated Slack chat channel; join the conversation.

The symposium at a glance

Schedule:

 

• Dates: May 6th (noon) - May 10th (early afternoon)
• Monday-Wednesday: Parallel sessions and poster presentations at MECC conference center (Google Maps).
• Thursday-Friday: Plenary sessions at Sint Jans Church in Maastricht city center (Google Maps).

Special Excursions:

Please register for the excursion via the Symposium registration form.

• May 5th (mid-mornig - afternoon): Explore scenic geology drilling site of ET.
• Morning of May 6th: Explore E-Test project location in Liege
• During Symposium: visit ETpathfinder project in the observation lounge

Additional information:

• Conference Fee: €350 before April 6th at 23:59 CEST / €400 after April 6th at 23:59 CEST. Pay upon registration (see payment information in side-menu)
• Parking: Free parking at Duboisdomein 30, 5 minute walk from MECC. See also the page “how to reach” [include link]
• Refreshments and lunch; Refreshments will be provided during the symposium and lunch on Tuesday and Wednesday.
• Exploration of Maastricht: Enjoy the lunch spots and terraces in the city center of Maastricht on Thursday and Friday noon.
• Accommodation; Please arrange your own; we're happy to provide suggestions: have a look at the "practical information" page accessible via the side-menu.

ETsymposium welcome slides.pdf

Monday, 6 May

09:00 → 12:00 Excursion E-TEST Liège (times TBC)

10:00 → 12:00 OSB: Pre-Session

ET Symposium Room 2.1

12:00 → 13:00 Registration

13:00 → 13:10 Welcome by LOC

13:10 → 15:00 ISB: Optical Layout / Detector Layout

Conveners: Anna Green (Nikhef), Jerome Degallaix (Laboratoire des Matéraux Avancés)

ET-Symposium Room 2.2

13:10 ET 10 km triangle: towards the updated detector layout

Speakers: Anna Green (Nikhef), Jerome Degallaix (Laboratoire des Matéraux Avancés), Mikhail Korobko

TDS Link

13:10 → 15:10 SCB/SPB

Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)

Zoom Room 2.3

13:10 Welcome to SCB session & Overview EMR technical site studies

Speaker: Wim Walk

Wim Walk ET Symposium presentation Maastricht final.pptx

13:30 Progress and learnings on EMR drilling operations

Speaker: G.J. Vis & B. Vink

GJV ET_Symposium_Maasticht_May2024_Monday 13.20 talk.pptx

13:50 Preliminary technical feasibility assessment based on Aubel's borehole results

Speaker: M. van Grootveld & P. Lamas

Patricia 240506_Engineering approach for Aubel's results.pdf

14:10 Plans and preliminary evaluations of EMR bore hole investigations: From logs and tests to core and rock mechanics

Speaker: Marius Waldvogel

Plans and preliminary evaluations of EMR bore hole investigations From logs and tests to core and rock mechanics.pptx

14:30 Hydrogeology: Planning and progress from EMR regional to local

Speaker: Philippe Orban

SPBMaastricht_060524.pptx

14:50 Geophysical imaging studies for the EMR site: Early results from recent electrical resistivity tomography and gravity measurements

Speaker: F. Nguyen

Geophysical imaging.pdf

13:15 → 14:00 OSB: DIV1

ET Symposium Room 2.1

13:15 Div 1 chairs

Speaker: Chris Van Den Broeck

OSB_Div1.pdf

13:30 Science overview: Fundamental Physics with ET

Speaker: Costantino Pacillo

14:00 → 15:00 OSB: DIV2

ET Symposium Room 2.1

14:00 Div 2 chairs

Speakers: Angelo Ricciardone, Dr Archisman Ghosh (Universiteit Gent), Mairi Sakellariadou

ET-DIv2-May2024.pdf

14:30 Gravitational Waves from Domain Wall Dynamics

Domain walls are topological defects that arise whenever a discrete symmetry is spontaneously broken. Being motivated in several Beyond the Standard Model scenarios, including axion-like particle models, domain walls are viable sources of a stochastic gravitational wave background with a broken power-law spectrum that could be detected by the near and far future third generation interferometers. In this talk, I will review the basics theoretical motivations and observational prospects for domain walls in gravitational wave experiments, including updated prospects for the ET sensitivities. I will also emphasise the importance of friction from particles in the surrounding plasma scattering against domain walls, which could affect the resulting gravitational wave emission.

presentation_Aaron_Rase_DWs_ET_Symposium.pdf

14:45 The astrophysical gravitational-wave background as a probe for both astrophysics and cosmology

The frequency spectrum of the stochastic gravitational wave background (SGWB) from compact binary coalescences has a characteristic peak that depends on the specific features of the source population, notably the mass and redshift distribution. The underlying cosmology has an impact as well, mainly through the value of the Hubble parameter. The peak of the SGWB can be used as an observable, complementary to resolved events, to constrain the astrophysics of sources and the cosmological evolution. This possibility becomes even more intriguing, as the Einstein Telescope is expected to detect the stochastic background with exceptional sensitivity. In this talk, I will present how the high-frequency shape of the SGWB from binary neutron stars can be used to gain insights into the underlying astrophysics and cosmology. Specifically, I will show how, through a Markov Chain Monte Carlo analysis, it is possible to constrain a selection of astrophysical and cosmological parameters, and I will discuss the applicability of these techniques to other sources of stochastic background expected to be observed with ET.

Speaker: Giulia Capurri (Università di Pisa)

The astrophysical gravitational-wave background as a probe for both astrophysics and cosmology

15:00 → 15:30 Coffee Break

15:30 → 16:15 ISB: Optical Layout / Detector Layout

Conveners: Anna Green (Nikhef), Jerome Degallaix (Laboratoire des Matéraux Avancés)

ET-Symposium Room 2.2

15:30 → 16:30 OSB: DIV2

ET Symposium Room 2.1

15:30 Model-independent cosmology with joint observations of gravitational waves and γ-ray bursts

The multi-messenger (MM) observations of binary neutron star (BNS) mergers provide a novel approach to trace the distance-redshift relation, crucial for understanding the expansion history of the Universe and, consequently, testing the presence of Dark Energy (DE). While the gravitational wave (GW) signal offers a direct measure of the distance to the source, the combined efforts of wide-field X-/gamma- ray observations and ground-based optical telescopes yield the redshift of the host galaxy. In my presentation, I will discuss the use of gamma-ray bursts from BNS mergers observed by high-energy satellites, such as the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory, to construct a large set of mock MM data through a complete posterior reconstruction of the GW parameters beyond the standard Fisher matrix approach. We explore combinations of current and future generations of GW detectors and work within various underlying cosmologies. I will present how these mock data are used to perform an agnostic reconstruction of the DE phenomenology, thanks to Machine Learning and Gaussian Process techniques. Our study highlights that the bottleneck in combined GRB-GW detection for generating meaningful cosmological inferences lies in the availability of GRBs with known redshifts in the coming years. We stress the need to couple future interferometers, like the Einstein Telescope, with a new set of high-energy satellites that can improve the sky localization of the events.

ET symposium PDF.pdf

Model-independent cosmology with joint observations of gravitational waves and γ-ray bursts

15:45 Unbiased standard siren cosmology with joint GW and GRB observations

Joint observations of gravitational-wave and GRB events are among the best standard siren prospects for cosmology. The actual possibility of obtaining an accurate measurement of the Hubble constant is however plagued by an intrinsic source of bias. This stems from the strong selection effect for the coincident detection of the GRB, which happens only for sources with particularly small inclination. We will show that this problem can be overcome by reconstructing the a-priori unknown electromagnetic detection probability from the data. This leads at the same time to an unbiased measurement of the Hubble constant, to infer the properties of GRB emission, and to measure the individual viewing angles in a precise and accurate way.

Unbiased standard siren cosmology with joint GW and GRB observations

16:00 On the impact of lensing on standard sirens measurements

Gravitational Waves (GWs) emitted by merging binaries of compact objects, when accompanied by an electromagnetic detection, can be used as “standard sirens” to probe the distance-redshift relation and the standard model of cosmology. However, we expect GW signals to be bent by the intervening matter field during their trajectory towards our detectors, a well-known phenomenon called gravitational lensing. This induces modifications on the measurement of the luminosity distance compared to that in a homogeneous universe. In this talk, I will present how lensing can impact the power of standard sirens for cosmological and astrophysical studies, in the scenario of third-generation ground-based GW detectors, in particular the Einstein Telescope. Treating lensing as a systematic error, I will point out that it can induce a bias in the estimation of the cosmological parameters and quantify it in relation to the characteristics of a catalog of future GW events. For our fiducial scenario, I will show evidence that lensing bias can be comparable to, or greater than, the forecasted statistical uncertainty of the cosmological parameters. Moreover, I will also discuss the impact of lensing on the neutron star mass distribution inferred from events without an electromagnetic counterpart. I will conclude by presenting some mitigation strategies that can be adopted in the data analysis.

On the impact of lensing on standard sirens measurements

16:15 Measuring the value of H0 using dark sirens and Sunyaev–Zeldovich galaxy cluster catalogues

The determination of the Hubble constant (H0) plays a crucial role in cosmology. Recent work has demonstrated the feasibility of constraining H0 through analysis of gravitational wave (GW) events without an electromagnetic (EM) counterparts and galaxy catalogues. This can be achieved using the publicly available gwcosmo package, with GW events from the GWTC3 catalogue and the GLADE+ galaxy catalogue. Despite the success in aligning with current state-of-the-art H0 measurements, the precision is severly limited by the incompleteness of galaxy catalogues. As a consequence, a significant fraction of the GW events that are situated at high redshifts become less informative due to their deficient redshift support.

In this presentation, I propose a novel approach which incorporates information from Sunyaev–Zeldovich (SZ) galaxy cluster catalogues. These catalogues are created using the SZ effect to detect large cluster gas masses and associating them with known clusters identified in EM surveys. The usage of SZ catalogues offers distinct advantages, including the provision of support up to higher redshifts and a more straightforward derivation of host probabilities via cluster masses. Initial findings suggest that integrating SZ catalogues into the existing methodology presents a promising avenue for refining H0 estimates derived from GW events, thereby enhancing our comprehension of cosmological parameters.

SZ_catalogues_ET_Symposium_presentation.pdf

15:30 → 18:15 SCB/SPB

Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)

Zoom Room 2.3

15:30 Results of the 3D modelling of Dinantian carbonates in North-West Europe and implications for the EMR subsurface

Speaker: Y. Vanbrabant

15:50 Introduction to Sardinia activities

Speaker: D. D'Urso

20240506_Intro_Sardinia_activities.pdf

16:10 New geochronologic and thermochronologic data from the Einstein Telescope candidate site of Sardinia

Speaker: Giovanni Luca Cardello

Cardello ET Maastricht (06 05 24) LC1.pdf

16:30 Civil and environmental engineering activities for the ET sustainable design in Sardinia

Speaker: Giuseppe Sappa (Sapienza, University of Rome)

Engineering activities for the ET in Sardinia_XVI ET Symp_SappaFinalVersion.pptx

16:50 Plan and progress of the seismic and magnetic noise monitoring studies in the EMR-region

Speaker: F. Nguyen

Noise and magnetic monitoring.pdf

17:10 Future active and passive seismic imaging campaigns in the EMR-region

Speaker: M. Kiehn

Kiehn_Future_Seismic_Imaging_Campaigns_in_EMR_region_SCB_SPB_Session_v06.pdf

17:30 Status of measurements in Sardinia

Speaker: Davide Rozza (INFN-LNS)

Sardinian_Updates_Rozza

17:50 Seismic noise characterisation at ET candidate sites

Speaker: A. Rietbrock & M. Lindner

16:15 → 17:15 ISB: HF Suspension Requirements

Convener: Stefan Hild

ET-Symposium Room 2.2

16:30 → 18:15 OSB: DIV7

ET Symposium Room 2.1

16:30 Div 7 chairs

Speakers: Cristiano Palomba, Ik Siong Heng (University of Glasgow), Marco Limongi

ET OSB div 7 Stellar collapse and spinning neutron stars.pdf

17:00 Localizing binary neutron star inspirals and constraining primordial black hole abundance using continuous wave methods in ET

Next-generation gravitational-wave detectors will provide unprecedented sensitivity to inspiraling binary neutron stars and black holes, enabling detections at the peak of star formation and beyond. However, the signals from these systems will last much longer than those in current detectors, and overlap in both time and frequency, leading to increased computational cost to search for them with standard matched filtering analyses, and a higher probability that they are observed in the presence of non-Gaussian noise. We therefore present a method to search for gravitational waves from compact binary inspirals in next-generation detectors that is computationally efficient and robust against gaps in data collection and noise non-stationarities. Our method, based on the Hough Transform, finds tracks in the time/frequency plane of the detector that uniquely describe specific inspiraling systems. We find that we could detect $\sim 5$ overlapping, intermediate-strength signals (matched-filter signal-to-noise ratio $\rho\approx 58$) without a sensitivity loss. Additionally, we demonstrate that our method can enable multi-messenger astronomy: using only low frequencies ($2-20$ Hz), we could warn astronomers $\sim 2.5$ hours before a GW170817-like merger at 40 Mpc and provide a sky localization of $\sim 20$ deg$^2$ using only one ``L'' of Einstein Telescope. Comparing matched filtering searches to our proposed method at a fixed sensitivity, we find a factor of $\sim10-$50 speed-up when we begin an analysis at a frequency of 5 Hz up to 12 Hz for a system with a chirp mass between $\mathcal{M}\in[1,2]M_\odot$. We also project constraints on stellar-mass and sub-solar mass primordial black hole abundance using our method.

et_symposium_bns_ew.pdf

17:15 Bridging Relativistic Jets from Black Hole Scales to Long-Term Electromagnetic Radiation Distances: a Moving-Mesh General Relativistic Hydrodynamics Code with HLLC Riemann Solver

Relativistic jets accompany the collapse of massive stars, the merger of compact objects, or the accretion of gas in active galactic nuclei. They carry information about the central engine and generate electromagnetic radiation. No self-consistent simulations have been able to follow these jets from their birth at the black hole scale to the Newtonian dissipation phase, making the inference of central engine property through astronomical observations undetermined. We present the general relativistic moving-mesh framework to achieve the continuity of jet simulations throughout space and time. We implement the general relativistic extension for the moving-mesh relativistic hydrodynamic code - JET, and develop a tetrad formulation to utilize the HLLC Riemann solver in the general relativistic moving mesh code. The new framework is able to trace the radial movement of relativistic jets from central regions where strong gravity holds all the way to distances of jet dissipation.

TDS link

17:30 How to make a neutron-star mountain out of a molehill

Speaker: Fabian Gittins (University of Southampton)

TDS link

17:45 The initial mass – remnant mass relation for core-collapse supernovae

Speaker: Cristiano Ugolini (SISSA)

TDS Link

18:00 Theoretical prediction and observed rates for CCSNe

Speaker: Ines Giudice

TDS link

17:15 → 18:15 ISB: Infra Interface Discussion

Conveners: Jan Harms, Stefan Hild

ET-Symposium Room 2.2

Tuesday, 7 May

09:00 → 10:45 EIB

Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco

Zoom Room 2.18

09:00 Update from Division 1

Speaker: Andres Tanasijczuk (Universite catholique de Louvain)

EIB-Div1_ET-Symposium_Maastricht_May-2024.pdf

09:15 Update from Division 2

Speaker: Antonella Bozzi

09:30 Update from Division 3

Speaker: Gonzalo Merino

20240507 ET Symposium Div3.pdf

09:45 Update from Division 4

Speaker: Steven Schramm (University of Geneva)

10:00 Update from TTG

Speaker: Sara Vallero (INFN Torino)

10:15 Discussion

09:00 → 10:45 ETO: Engineering

Convener: Patrick Werneke

ET Symposium Room 2.3

TDS link

Zoom Link ETsymposium Room 2.2

09:00 Civil engineering for the design of large underground research infrastructure - The experience of CERN and collaboration with ETO.

Speaker: John Andrew Osborne (CERN)

07_05_2024_Maastricht_CERN_Final

09:30 ETO collaborative framework for Civil Engineering studies

Speaker: maria marsella (Sapienza University, Rome)

070524_ETO CE_Marrsella

09:55 Technical steps for delivering a reference detector layout

Speaker: Max Majoor (Nikhef)

TDS link

10:20 Geotechnical challenges for underground civil engineering

Speaker: Jonathan Bratanata (Nikhef)

Geotechnical Challenges for Underground Civil Engineering of Einstein Telescope

09:00 → 10:45 ISB: Integrated LF Tower Design

Convener: Steffen Grohmann (KIT)

ET-Symposium Room 2.2

09:00 → 10:30 OSB: DIV3

ET Symposium Room 2.1

09:00 Div 3 chairs

Speakers: Antonio Riotto (Université de Genève), Giulia Cusin, Michela Mapelli

Division 3 Chairs' report

09:30 Classifying binary black holes from Population III stars with the Einstein Telescope

Third-generation (3G) gravitational-wave (GW) detectors like the Einstein Telescope (ET) will observe binary black hole (BBH) mergers at redshifts up to z ∼ 100. However, unequivocal determination of the origin of high-redshift sources will remain uncertain, due to the low signal-to-noise ratio (SNR) and poor estimate of their luminosity distance. This study proposes a machine learning approach to infer the origins of high-redshift BBHs, specifically differentiating those arising from Population III (Pop. III) stars — likely the first progenitors of stellar-born BBH mergers in the Universe — and those originated from Population I-II (Pop. I-II) stars. We have considered a wide range of state-of-the-art models encompassing current uncertainties on Pop. III BBH mergers. We then estimate parameter errors of detected sources with ET using the Fisher-information-matrix formalism, followed by classification using XGBoost, a machine learning algorithm based on decision trees. For a set of mock observed BBHs, we provide the probability that they belong to the Pop. III class while considering the parameter errors of each source. In our fiducial model, we accurately identify ∼ 10% of detected BBHs originating from Pop. III stars with > 90% precision. Our study demonstrates how machine learning enables to achieve some pivotal aspects of ET science case by exploring the origin of individual high-redshift GW observations. We set the basis for further studies, which will integrate additional simulated populations and account for population modeling uncertainties.

Classifying binary black holes from Population III stars with the Einstein Telescope

PopIII_classifier.pdf

09:45 Primordial Black Holes or else? Tidal tests on subsolar gravitational-wave observations

The detection of a subsolar object in a compact binary merger is regarded as one of the smoking gun signatures of a population of primordial black holes (PBHs). We critically assess whether these systems could be distinguished from stellar binaries, for example composed of white dwarfs or neutron stars, which could also populate the subsolar mass range. At variance with PBHs, the gravitational-wave signal from stellar binaries is affected by tidal effects, which dramatically grow for moderately compact stars as those expected in the subsolar range. We forecast the capability of constraining tidal effects of putative subsolar neutron star binaries with current and future LIGO-Virgo-KAGRA (LVK) sensitivities as well as next-generation experiments like Einstein Telescope and Cosmic Explorer. We show in particular that the improvement in sensitivity for 3G detectors can rule out or confirm different exotic compact object models, as well as better distinguish between signals generated by PBHs and BNSs.

ET Symposium Presentation.pptx

TDS link

10:00 Unveiling the formation of intermediate-mass black holes in dense star clusters with ET

Intermediate-mass black holes (IMBHs) are elusive objects that may represent the link between stellar-mass (BHs) and supermassive black holes (SMBHs). The current scarce observational evidence of IMBHs in the mass range 10^3-10^4 Msun leads to a natural question, are IMBHs a real category of BHs or, rather, do they represent exceptionally massive stellar BHs and light SMBHs?
In this talk, I will show how ET can place constraints on the mass spectrum of IMBHs and deliver crucial insights into the processes that regulate IMBH formation.

TDS

10:15 Stellar black hole mergers as probes of cosmic chemical evolution

The gravitational waves we observe today come from merging black holes that have formed throughout the entire Universe.
Their population properties encode valuable information about how stars form and evolve in galaxies very different from our own. They are also sensitive to, and can shed light on, the uncertain early history of element production in our Universe.
I will discuss the current empirical constraints on the low-metallicity cosmic star formation history and the implications for GW astrophysics with BBH mergers.
In the era of next generation GW detectors, the population properties of these mergers could potentially be used to complement electromagnetic studies of the chemical evolution of galaxies. I will discuss this emerging possibility in my talk.

MChruslinska_ET_symposium_May24.pdf

10:45 → 11:15 Coffee Break

11:15 → 13:00 EIB

Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco

Zoom Room 2.18

11:15 Discussion on General picture

Speaker: Stefano Bagnasco

TDS slides

12:00 IGWN ops experience

Speaker: Dr Duncan Macleod (Cardiff University)

12:30 Discussion

11:15 → 13:00 ETO: Engineering

Convener: Patrick Werneke

ET Symposium Room 2.3

TDS link

Zoom Link ETsymposium Room 2.2

11:15 ET reference system

Speaker: Alessio Rocchi (INFN Roma Tor Vergata)

Slides on the TDS

11:30 Beampipe requirements

Speaker: Marije Barel (Nikhef)

20240503 - ET beampipe requirements - symp Maastricht - MYB

12:00 Updates from beampipe vacuum studies at CERN

Speaker: Carlo Scarcia

TDS Link

12:30 Pilot sector at CERN and beampipe installation

Speaker: Luigi Scibile

SCIBILE_XIV_ET_symposium_Maastricht_2024_v1.pptx

11:15 → 12:00 ISB: Integrated LF Tower Design

Convener: Steffen Grohmann (KIT)

ET-Symposium Room 2.2

11:15 → 11:45 OSB: DIV3

ET Symposium Room 2.1

11:15 Measuring cosmic star formation with next Generation GW detectors

One of the most exciting prospects of next-generation gravitational-wave (GW) detectors is their ability to detect double compact object (DCO) mergers at extremely high redshifts. These observations might enable us to use GW detections as an independent measure of the cosmic star formation rate out to unprecedentedly high redshifts. Measuring cosmic star formation with GW is (supposedly) particularly promising for tracing the lowest-metallicity star formation, which is most challenging to measure with other traditional methods.

However, before we can realize this science case, we need to address several crucial questions: How well do we understand the delay-time distribution of GW sources, and can we link them to other observables, such as the masses? Do we know how 'old the black holes that we see merging today are?, and Why do we expect DCO mergers to form efficiently at low metallicity, and how robust is this finding?

In this talk, I will discuss the state of the field regarding the prospects of using next-generation GW detectors to measure cosmic star formation. I will also present new results that explain why we expect binary black hole formation to be metallicity-dependent, while binary neutron star formation is not.

ET_symposium_GW_and_SF.pptx

11:30 Probing primordial black holes with ET

Speaker: Ville Vaskonen

ET-0251A-24

11:45 → 12:30 OSB: DIV5

ET Symposium Room 2.1

11:45 Div 5 chairs

Speakers: Monica Colpi, samaya nissanke

Introduction division 5

Samaya_ETDiv5ETSymposium0524.pdf

11:55 EPTA and PTA synergies with ET

Speakers: Aditya Parthasarathy (ASTRON), Delphine Perrodine (INAF)

12:15 Directional response of the Astrometric Gravitational Wave Antenna in the context of multimessenger synergies

Since the first detection of gravitational waves, the field of experimental gravitation is steadily working on improving the current detectors as well as developing new instruments in order to expand the range of observable frequencies and improve the reconstruction of GW direction and source parameters.
In such a context, the Astrometric Gravitational Wave Antenna (AstroGraWAnt, see for details https://doi.org/10.1038/s41598-024-55671-9) - which is based on differential relativistic astrometry and is devised as a telescope pointing simultaneously at three (or more) pairs of line-of-sights - represents a promising concept to achieve the aforementioned goals.
The talk focuses on two fundamental performance characterizations of AstroGraWAnt.
First, after recalling its operational principle, we present how AstroGraWAnt collects gravitational wave signals from arbitrary directions, by deriving its pattern functions for different configurations.
Second, we compare the above results with the directional response of other detectors, and we discuss complementarities and possible advantages achievable with the astrometric antenna, like, e.g., a quasi-isotropic sky coverage.
Finally, we evaluate more convenient configurations for AstroGraWAnt, highlighting how the combination of more antennas – or, equivalently, employing more than three pairs of line-of-sights - is a way to reach higher values in the sky localization of the sources.

ET-0241A-24

12:00 → 13:00 ISB: Controls / Electronics

Conveners: Bas Swinkels (Nikhef), Dr Loic Rolland (LAPP)

ET-Symposium Room 2.2

12:00 Electronic standards

Speakers: Bas Swinkels (Nikhef), Dr Loic Rolland (LAPP)

ET-0260A-24

13:00 → 14:00 Executive Board

13:00 → 14:00 Lunch Break

14:00 → 16:00 ETO: Project Office

Convener: Alessandro Variola (Istituto Nazionale di Fisica Nucleare)

ET Symposium Room 2.3

TDS link

Zoom Link ETsymposium Room 2.2

14:00 Nomenclature

Speaker: Dr Leonardo Lucchesi

ET Nomenclature

ETPO_WP7_slides_Nomenclature_ETSymp_20240507.pptx

14:45 Design phase change process

https://apps.et-gw.eu/tds/ql/?c=17239

Speaker: Dr Christian Olivetto

Design phase change process

ET-0221A-24_RequestForChanges.pptx

15:20 Risks and requirements

Speakers: Dr Ghada Mahmoud, Romano Meijer

risk analysis

Risk Presentation- ET Symposium Maastricht V02.pptx

Symposium2024_SE_RM_V03

Symposium2024_SE_RM_V03.pptx

14:00 → 15:45 ISB: Contributed Talks

Conveners: Jan Harms, Stefan Hild

ET-Symposium Room 2.2

14:00 E-TEST: cryogenic radiative cooling of a 100kg suspended payload, from design to test.

E-TEST (Einstein Telescope Euregio-Meuse-Rhine Site and Technology) was a project funded by the European program Ineterreg Euregio Meuse-Rhine. One of the goals of the E-TEST project was to develop a prototype whose suspended payload would be cooled radiatively, i.e. without contact, to cryogenic temperature below 25K.

The prototype architecture relies on an active platform providing low-frequency active isolation on top of which is mounted an inverted pendulum. From the inverted pendulum platform is suspended a marionette through a GAS filter. The cryogenic payload is then suspended from the marionette. The payload consists of 100kg dummy mirror suspended itself from a cold platform hosting cryogenic sensors.
The cooling strategy is based on an external cryostat acting as heat sink for the internal cryostat supported by the suspended cold platform. The external cryostat is completely mechanically decoupled from the suspended assembly. The external cryostat is composed of a LN2-cooled radiative shield limiting the heat load towards the internal layer that is actively cooled by gaseous Helium provided by our Linde TCF20 Helium refrigerator.

Radiative cooling to cryogenic temperature usually requires very large radiating area to evacuate the heat from the payload. The estimated heat to be evacuated is around 250mW. Considering an emissivity of 50%, a heat sink at 20K and a target temperature of 25K, the required exchange area to evacuate the heat load would be 75m². To provide the necessary radiative exchange factor between the internal and external cryostat, an innovative compact radiative radiator concept was therefore developed. The ensure compactness, the exchange area is increased by interleaving non-touching fins mounted on the suspended and external cryostat. The thickness of the fins was optimised with respect to stiffness and heat spreading while minimising the mass to avoid jeopardizing the cooling time. A specific paint was then applied to ensure a high emissivity at cryogenic temperature.

The test was conducted in the FOCAL6.5 vacuum chamber at the Centre Spatial de Liège between November 21st and December 12th 2023. After 19 days of cooling, the dummy mirror and cold platform reached 22K.
The presentation will give an overview of the project, review the key design features of the prototype and its cryostat and summarise the achieved temperatures during the test.

Cryogenic radiative cooling of a 100kg suspended payload: from design to test

14:20 Cryopump concept of ET-LF - vacuum pumping and heat load aspects

In order to achieve the demanding vacuum conditions in ET-LF around the cryogenic mirror, extensive TPMC simulations with the in-house code ProVac3D have been performed to find an appropriate concept of cryopumps. Herewith, it was distinguished between light gases like hydrogen and heavy gases like water. Since the gas flows to be managed as well as the requirements are strongly different, the pumping concept comprises sections at 80 K for water pumping and sections at 3.7 K for hydrogen. It turned out that for water not the pressure requirement is the design driving value but an acceptable time for the built-up of one monolayer water at the mirror as the required upper limit by optic reasons.
While all vacuum demands where fulfilled, thermal aspects around the mirror with its limited thermal budget required further design elements.
In this presentation, all relevant simulation results, justifying the cryopump concept, are shown. Furthermore, all additional design aspects for the thermal management are explained. Finally, the recently available assumption of the resulting cryopump heat loads, important to scale the needed cryogenic infrastructure, is given.

Cryopump concept of ET-LF - vacuum pumping and heat load aspects

14:40 Towards Controls Noise Co-Design for the ET-LF, Test Mass Seismic Attenuation and Suspensions

The Einstein Telescope, low-frequency interferometers (ET-LF) will extend the detection band for gravitational-waves down to 3Hz [1]. Reaching these low-frequency sensitivities requires orders-of-magnitude improvements beyond the designs of second generation observatories, advanced LIGO [2] and Advanced Virgo [3]. Experience with these existing detectors has shown that they have been limited by technical and other noise sources below tens of Hertz [4, 5], upon reaching astrophysically significant sensitivities. Consequentially technical noises must be considered, as a matter of design, to ensure that the ET-LF observatory meets its sensitivity requirement.

One core subsystem of the ET-LF design is the test mass seismic isolation and suspension system. This has the primary goals of ensuring the core optics operate as free masses in the gravitational-wave detection band, isolating these mirrors from ground displacements, and providing a controls interface to ensure that the interferometer remains at its operating point. These goals are constrained by the requirements to not spoil the observatory’s sensitivity with suspension thermal noise or technical noise injection. Previous system level studies [6] of the baseline test mass seismic isolation and suspension system showed that the inclusion of just the simplest technical noise exceeds the sensitivity requirement for ET-LF.

We present a test mass seismic isolation and suspension concept which satisfies the ET-LF sensitivity for this simplest technical noise requirement. To meet this constraint the conceptual design includes key aspects of controls co-design for the test mass seismic isolation and suspension. As a first step the baseline design is extended with an active inertial isolation platform. Secondly the warm and cryogenic suspension stages must include key controls co-design principles which are most simply achieved with adjustments to their mechanical design. Care is taken to ensure the cryogenic suspension is adjusted in ways consistent with detailed thermal noise and cooling studies [7]. With these alterations optimal controls techniques are used to distribute longitudinal interferometric actuation over the suspension’s three penultimate stages, thus satisfying ET-LF’s sensitivity requirement.

[1] Einstein Telescope Steering Committee, “Design report update 2020: for the einstein telescope,” Einstein Telescope Collaboration, Tech. Rep. ET-0007B-20, 11 2020. [Online]. Available: https://apps.et-gw.eu/tds/ql/?c=15418
[2] J. Aasi, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, K. Ackley, C. Adams, T. Adams, P. Addesso, and R. X. Adhikari, “Advanced ligo,” Classical and quantum gravity, vol. 32, no. 7, p. 074001, 2015. [Online]. Available: https://iopscience.iop.org/article/10.1088/0264-9381/32/7/074001
[3] M. Agathos, K. Agatsuma et al., “Advanced virgo: a second-generation interferometric gravitational wave detector,” Class. Quantum Grav, vol. 32, no. 2, pp. 24 001–24 052, 2015. [Online]. Available: https://iopscience.iop.org/article/10.1088/0264-9381/32/2/024001
[4] LIGO Scientific Collaboration, Virgo Collaboration et al., “Gw150914: The advanced ligo detectors in the era of first discoveries,” Phys. Rev. Lett., vol. 116, no. 13, p. 131103, Mar. 2016. [Online]. Available: https://link.aps.org/doi/10.1103/PhysRevLett.116.131103
[5] F. Acernese, T. Adams et al., “Advanced virgo status,” Journal of Physics: Conference Series, vol. 1342, no. 1, p. 012010, jan 2020. [Online]. Available: https://dx.doi.org/10.1088/1742-6596/1342/1/012010
[6] N. A. Holland, C. M. Mow-Lowry, and Einstein Telescope Collaboration Active Noise Mitigation Division, “A systems approach to evaluating the status of ET-LF seismic attenuation proposals,” in Gravitational-Wave Advanced Detector Workshop 2023: Low Frequency Noise, Control and Sensing, 05 2023. [Online]. Available: https://agenda.infn.it/event/32907/contributions/200472/
[7] X. Koroveshi, L. Busch, E. Majorana, P. Puppo, P. Ruggi, and S. Grohmann, “Cryogenic payloads for the design with heat extraction, suspension thermal noise analyses,” Phys. Rev. D, vol. 108, p. 123009, Dec 2023. [Online]. https://link.aps.org/doi/10.1103/PhysRevD.108.123009

Towards Controls Noise Co-Design for the ET-LF, Test Mass Seismic Attenuation and Suspensions

15:00 Tower Vacuum makes progress in defining the civil interfaces

This talk is focusing on elements of "tower vacuum" systems that are critical for interfacing with civil infrastructure, in line with the current activities of ET.
Solutions are provided for the access mode (bottom/lateral) of "towers", for the size of extra rooms for auxiliaries and maintenance equipment, and about typical spaces requirements around main chambers. We will address the different clean areas as foreseen for different "towers compartments", together with the needed nearby access areas, adding details on clean air supply quality and quantity, during both operation and installation phases.
Also, we list typical needs from "conventional plants" (HVAC, pressurized air distribution, electrical mains, network…), remarking that these are not actually conventional but specific to GW interferometers, which must take into account the environmental disturbances potentially transmitted to sensitive parts.
Finally, we will share tables summarizing the main characteristics "per tower" ,such as access mode, diameter, total height, ….

Tower Vacuum makes progress in defining the civil interfaces

15:20 Installation of the Omnisens inertial isolation system.

To achieve its ambitious scientific goals [1], the Low-Frequency Einstein Telescope observatory aims for orders-of-magnitude reduction in residual strain noise between 3-10 Hz compared to current detectors. Many noises affecting the 3-10 Hz band are driven by ground vibration and the resulting residual motion of the interferometer optics. These noises have been a challenge to deal with in second-generation GW detectors [2, 3], and threaten to severely impact the low-frequency sensitivity of ET-LF unless substantial improvements in the initial stages of the seismic isolation chain are developed.

The Omnisens experiment is a novel in-vacuum inertial isolation system based on six-dimensional interferometric sensing of a reference test-mass [4]. The three-armed test-mass is suspended from the inertial platform using a high-quality-factor fused-silica suspension system. Thanks to its large moment of inertia and to the overlap of its centre-of-mass with its centre-of-rotation, the test-mass has a tilt resonance frequency lower than 10 mHz.
The relative position of the test-mass with respect to the inertial platform is sensed using six compact Homodyne Quadrature Interferometers (HoQI) [5].
A high-gain control system actuates on the inertial platform to make it follow the suspended test mass. Low-noise is achieved in all six degrees of freedom, suppressing the effect of cross-couplings thus allowing to distinguish rotation from translation.

The presentation will discuss the status of the Omnisens experiment currently being assembled in Amsterdam and its future commissioning and characterisation.
Most recent updates include the suspension of the test-mass from the fused-silica fibre, the assembly and on-going installation of the active inertial platform and the measurement of the performance achieved by the matured-design Omnisens HoQI detectors.
The presentation will also treat well known problems such as long-term drifts of the suspended test-mass orientation and thermal gradients, which will be addressed by the installation of thermal shields, centre-of-mass tuners, and low-noise electrostatic drive actuators acting on the suspended test-mass.

[1] Einstein Telescope Steering Committee, “Design report update 2020: for the einstein
telescope,” Einstein Telescope Collaboration, Tech. Rep. ET-0007B-20, 11 2020. https://apps.et-gw.eu/tds/ql/?c=15418

[2] Martynov D V et al 2016, Sensitivity of the advanced ligo detectors at the beginning of gravitational wave astronomy Phys. Rev. D 93 112004. https://doi.org/10.1103/PhysRevD.93.112004

[3] Acernese, F., T. Adams, K. Agatsuma, L. Aiello, A. Allocca, A. Amato, S. Antier, et al. “Advanced Virgo Status.” Journal of Physics: Conference Series 1342, no. 1 (January 1, 2020): 012010. https://doi.org/10.1088/1742-6596/1342/1/012010.

[4] Mow-Lowry, C M, and D Martynov. “A 6D Interferometric Inertial Isolation System.” Classical and Quantum Gravity 36, no. 24 (November 14, 2019): 245006. https://doi.org/10.1088/1361-6382/ab4e01.

Presentation

14:00 → 15:00 OSB: DIV6

ET Symposium Room 2.1

14:00 Div 6 chairs

Speaker: Tanja Hinderer

TDS link

14:30 Problematic systematics in neutron-star merger simulations

With the next generation of gravitational-wave observatories, the Einstein Telescope and Cosmic Explorer, we will have the opportunity to peer deeper into the gravitational-wave signal from merging neutron-star binaries and extract valuable information about the state of ultra-dense nuclear matter. In order to conduct this parameter inference reliably, we require waveform models that faithfully capture the correct physics. The early inspiral waveform is accurately described using the post-Newtonian approximation. However, close to merger, full, non-linear general relativity must be solved with numerical simulations. In this presentation, I will explore how artificial thermal effects associated with the neutron-star surface impact on the tidal dynamics and the inferred properties.

Speaker: Fabian Gittins (University of Southampton)

TDS link

14:45 Revealing the strength of three-nucleon interactions with the Einstein Telescope

Three-nucleon forces are really important for understanding nuclear systems, including the dense matter found in neutron stars. In this study, we looked at different nuclear Hamiltonians that can accurately describe two-nucleon scattering data and properties of light nuclei, but differ in the three-nucleon interactions among neutrons. Although we didn't find any significantly improved constraints from current astrophysical data, we found that future observations of neutron star mergers with detectors like the proposed Einstein Telescope could provide really strong evidence to distinguish between these Hamiltonians.

Speakers: Peter Pang (Nikhef), Dr Peter T. H. Pang

ET-0235A-24.pdf

15:00 → 16:00 OSB: DIV8

ET Symposium Room 2.1

15:00 Div 8 chairs

Speaker: Harald Pfeiffer (Max-Planck-Institute for Gravitational Physics)

TDS link

15:30 Gravitational wave signatures of intermediate-mass black holes

In this talk, we present a systematic study of potential gravitational wave signatures produced by binary black hole coalescence, resulting in the production of an intermediate-mass black hole (IMBH). The event GW190521 represents the first direct evidence of the existence of IMBHs and suggests that more IMBHs might be detected when more data are collected, especially when more sensitivity is achieved in the low-frequency region, which characterises this type of events. We investigate a few million simulated waveforms corresponding to coalescence events whose remnant mass falls in the range $100

IMBH-inguglia.pdf

15:45 Systematic Biases in Estimating the Properties of Black Holes Due to Inaccurate Gravitational-Wave Models

Gravitational-wave (GW) observations of binary black-hole (BBH) coalescences are expected to address outstanding questions in astrophysics, cosmology, and fundamental physics. Inference of BBH parameters relies on waveform models, and realizing the full discovery potential of upcoming facilities (such as the Einstein Telescope) hinges on the accuracy of these waveform models. Using linear-signal approximation methods and Bayesian analysis, we start to assess our readiness for what lies ahead using two state-of-the-art quasi-circular, spin-precessing models. We find that systematic biases increase with the spin of the BH. We ascertain that current waveforms can accurately recover the distribution of masses in the LVK astrophysical population, but not spins. For more extreme binary parameters, we find that systematic biases increase with detector-frame total mass, binary asymmetry, and spin-precession, with a majority of such binaries incurring parameter biases. Finally, we examine in detail three 'golden' events characterized by high mass ratios and spins.

24May_Maastricht.pdf

TDS link

15:45 → 16:15 Coffee Break

16:15 → 18:00 ETO: Roadmap

Conveners: Andreas Freise, Fernando Ferroni (INFN Roma 1)

ET Symposium Room 2.3

TDS link

Zoom Link ETsymposium Room 2.2

17:30 → 19:00 Posters

17:30 Updates on ARC: R&Ds for ET, cryogenic strategies without cryo-liquids

The Amaldi Research Center (ARC), located in Sapienza University of Rome, will host the first experiment of a cooling system for an actual-sized cryogenic payload. Following the solid conduction cooling scenario, two refrigeration lines, each driven by two Pulse Tubes cryocoolers, will be used to cooldown a cryogenic payload hosted in a specifically designed 3 m tall cryostat.
While one refrigeration line has already been built, the other, along with the cryostat and the payload, is now under construction and will be ready in 2025.
Before that date, the entire system must be properly designed and simulated to ensure the success of the cooling and to optimize the cooling time.
Hence, several experimental tests and simulations are progressing.
The goal is to investigate the thermal properties of the components of the solid conduction path from the cryocoolers to the mirror and the mechanical properties of the sapphire elements of the payload suspensions.

Updates on ARC.pdf

Updates on ARC: R&Ds for ET, cryogenic strategies without cryo-liquids

17:31 Mitigating back-scatter light with quantum-enhanced dual homodyne readout

Back-scatter light is one of the main technical limitations on the sensitivity of the detectors. Minimizing it requires significant effort in optimizing surfaces, implementing baffles and other advanced instrumentation techniques. As the last line of defense, the dual homodyne readout was proposed to sense and subtract the noise introduced by back-scattered light. However, till now this approach was not compatible with frequency-dependent squeezing. In our work we extend the dual homodyne approach to take full advantage of frequency-dependent squeezing. We theoretically study the concept and discuss its advantages, possible configurations and potential limitations. Crucially, we show that quantum-enhanced dual homodyne readout can be implemented without modification of the core optical design. We further discuss its applications in GW detection beyond mitigation of back-scatter light.

Mitigating back-scatter light with quantum-enhanced dual homodyne readout

17:32 Volatile Residue of hydrocarbons in ET: a UHV chamber for CRDS at the CIRCE laboratories

A significant challenging aspect of the ET vacuum system is the requirement on the hydrocarbon partial pressure ($p_{hy}$) for molecules heavier than 100 atomic mass unit (amu), as reported in the ET design report:
\begin{equation}
p_{hy}\le1\cdot10^{-14}\,mbar
\end{equation}
In order to reach this partial pressure, both the non volatile and volatile residue of hydrocarbons should be considered.
The former is strictly related to the cleanliness level of the internal surfaces of the system, the latter might give a non negligible contribution to the partial pressure in the final vacuum system.
However, accurately measuring hydrocarbon partial pressure under vacuum conditions is complex. The typical approach in Ultra High Vacuum (UHV) conditions involves using a Residual Gas Analyzer (RGA).
Generally, is not simple to distinguish the contribution of different molecules in the spectrum of the instrument. Indeed, the RGA analysis requires a deep knowledge of the typical cracking pattern of the molecule that complicates the identification of many partial pressures in a vacuum system.
In the present work we want to introduce a new facility in UHV, which will be able to perform really accurate measurements of $p_{hy}$ using an extremely high sensitive technique like Cavity Ring-Down Spectroscopy (CRDS). This technique is based on the measurement of the cavity ring-down time, which gives information about the intracavity absorber concentration and hence gas pressure.
This system marks the first application of CRDS in UHV conditions, aiming to measure only lighter hydrocarbons ($<$ 100 amu).
However, CRDS it is rather promising in measuring $p_{hy}$ at the stringent levels required for ET, especially in the perspective to use it in the chain of processes for the UHV cleaning test, complementing the established Fourier-Transform Infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) techniques.

Volatile Residue of hydrocarbons in ET: a UHV chamber for CRDS at the CIRCE laboratories (P#03)

17:33 Signal-recycling cavity lock with a sub-carrier laser

The current error signal for the SRC length control, based on the frontal modulation scheme, is sub-optimal for a detuned operation of the interferometer. At the GEO600 detector, we tested a new SRC locking technique that is more suitable for transitioning the detector to a detuned state. The new technique is based on detecting changes in the SRC length by injecting an auxiliary sub-carrier field from the dark port of the interferometer. The sub-carrier field shares the same path with the squeezed light.

Bergamin.pdf

17:34 Towards the development of advanced opto-electronic components for ET: The ETICO2 laboratories

The Italian Einstein Telescope Infrastructure Consortium (ETIC) is an initiative led by the INFN with the aim of establishing a nationwide network of laboratories dedicated to advancing technologies and components crucial for the future Einstein Telescope gravitational wave Interferometer, alongside comprehensive characterization efforts for the Sos-Enattos site in Sardinia, Italy.
This abstract introduces the blueprint for ETiCo2 laboratories, planned to be established at the INFN-CA and the University of Cagliari Physics department. These state-of-the-art facilities will be dedicated to the development, fabrication, and characterization of new opto-electronic devices essential for monitoring and controlling the future ET Interferometer. Additionally, the laboratories will undertake the design, manufacture, and testing of dielectric materials and multi-layer coatings, with a focus on structural, morphological, and thermo-optical properties crucial for enhancing mirror functionalities.

Invio e-mail ETIC-ET_Maastricht_Final-1.pdf

17:35 Two-coloured laser light to control the Einstein Telescope

The proposed Einstein Telescope (ET) will employ laser light to meticulously monitor the distance between two freely hanging mirrors suspended kilometres apart, enabling the precise detection of subtle distortions in spacetime known as gravitational waves.

For ET to achieve sensitivities greater than 10^-24/sqrt(Hz), various new technologies need to be developed and tested. One of these new advancements will be the switch to silicon based mirrors. Because of silicon's high absorption at lower wavelengths, new laser wavelengths are required. Two proposed solutions are the wavelengths of 1550nm and 2090nm, but these still need considerable development before implementation.

The Two-Colour Project aims to combine these two wavelengths to create a controlling system, based on principles used in the ALS (Arm Length Stabilisation) [4] system from current detectors. Additionally this concept could provide a solution for the poor photodetector characteristics at > 2 μm.

Two-coloured laser light to control the Einstein Telescope

17:36 A fibre-based interferometric displacement sensor for the Einstein Telescope

New scientific innovations are currently being studied for improving the seismic isolation of the Einstein Telescope over second generation gravitational wave detectors. Especially in the area of displacement and inertial sensors, a lot of progress has been made within the last decades. Here, we will present our concept of a compact fiber-based displacement sensor, consisting of a heterodyne interferometer connected to a miniaturized sensor head by an optical fibre. As the sensor head will consist of a Meta-structure, which acts like a lens and a polarising beam splitter at the same time, the displacement sensor is desirable compact and hence easy to implement into an optical setup while targeting a sensitivity below 1 pm/$\sqrt{Hz}$ between 1 Hz and 200 Hz.
Besides the concept of the sensor, we will discuss the construction of the Meta-structure optical head and the measurements we performed to estimate the noise floor of our interferometric readout. In our interferometer, we assign the reference and the probe signal with a different frequency and a different polarisation. In order to minimize the noise that is not common for both signals, we send both through the same fibre and separate them only inside the optical head. As the polarisation states of the signals are orthogonal, they might not experience the same fibre noise. Therefore, we will study the noise induced by the fibre as well as the noise induced by our optical readout scheme itself. In order to do this, we built a mimic of our proposed sensor head and performed the associated measurements. We will show the results we achieved so far, reaching a sensitivity of 2 pm/$\sqrt{Hz}$ between 10 Hz and 100 Hz. Finally, we give an outlook on the noise sources we are going to investigate in the future to further reduce the noise power of our displacement sensor.

Speaker: Johannes Bäuerlein (Max Planck Institute for Gravitational Physics (AEI) Hannover, Laserinterferometrie & Gravitationswellen-Astronomie)

displacement_sensor_poster_baeuerlein_carter_klein_fluegel_paul.pdf

17:37 Low energy electron to actively cure frost and electrostatic charging issues in future gravitational wave detectors

In the upcoming third generation of gravitational wave (GW) detectors, electrostatic charging, and the build-up of a frost layer on cryogenically cooled mirrors may represent two potentially critical showstoppers for GW detection. Here we approach a possible mitigation solution for both such apparently uncorrelated issues, relying on optics irradiation with low energy electrons (few hundreds eV).

Electrostatic charge has been shown to affect LIGO data taking. Its mitigation routinely requires mirror’s long exposures (hours) to a relatively high pressure (tenth of mbar) of N$_2$ ions flux.
Cryogenic mirrors in future GW detectors are ideal to reduce thermal noise and to obtain the desired detection sensitivity at low frequency. However, operating at temperatures ~10 K presents several challenges, one being on the cryogenic vacuum system hosting the cold mirrors. Gases composing the residual vacuum will tend to cryosorb on the mirror surfaces forming a contaminant ice layer (“frost”). This can severely perturb mirror optical properties preventing detection with the design sensitivity.
Noticeably, the method used at LIGO to mitigate electrostatic charging cannot be applied on cryogenically cooled mirrors without forming on its surface an unacceptably thick condensed N$_2$ layer.
Low energy electrons are known to interact only with the very top layers (some nm) of any irradiated surface, are known to be very efficient in inducing gas desorption and, by properly tuning the energy of the incident electrons, can neutralize both positive and negative charges on surfaces. Therefore, low energy irradiation of mirrors’ surfaces seems ideal to neutralize charge and induce frost desorption without damaging the mirror surfaces’ optical properties.

Here we present the main experimental activity, ongoing at LNF-INFN, demonstrating that low energy electrons may be indeed used as a mitigation method to cure surface charging and frost formation.

Speaker: Roberto Cimino

Spallino_et al_XIV_ETSymposium_poster.pdf

17:38 Status of cryostat design for cryogenic payload suspension studies for the Einstein Telescope

The Einstein Telescope (ET) is a third generation gravitational wave detector planned in Europe, combining a low-frequency (LF) and a high-frequency (HF) laser interferometer. Cryogenic operation of ET-LF in the temperature range of 10 K to 20 K is essential to suppress the suspension thermal noise, which dominates the detection sensitivity at
frequencies below 10 Hz. This requires suspension materials with high thermal conductivity and low mechanical dissipation at cryogenic temperatures. The baseline design currently considers two suspension concepts, using monocrystalline suspension fibers made of silicon or sapphire,and/or a thin-wall titanium suspension tube filled with static He-II. The mechanical Q-factor provides physical insight into dissipative mechanisms of material samples and their applicability as cryogenic suspensions in gravitational wave detectors. It is measured by the ring-down method, exciting the suspensions to resonant vibrations and analyzing the decay time. For this purpose, a test facility is being designed that enables full-size studies with various suspension materials and geometries. This includes also the integration of a noise-free He-II supply for investigating dissipation mechanisms in the static He-II column inside suspension tubes, which is a new field of research. We present the design progress,including specific design conditions imposed by the experimental campaigns.

17:39 ETIC GEMINI @ LNGS - an underground facility to develop ET vibration control

A new underground facility is under construction at the National Laboratories of Gran Sasso for the development of a vibration sensing and control system of two suspended mechanical platforms. In this poster, we will present the goals of this experiment and provide an update on the status of the project.

17:40 Experimental facility to measure light scattering properties: BSDF and TIS

A new facility at INFN and University of Padova to measure light-scattering properties of surfaces and materials of interest for ET is described. Our system can measure the Bidirectional Scattering Distribution Function (BSDF) and Total Integrated Scattering at 532 nm and 1064 nm, with a plan to upgrade at 1550 nm in the near future. The BSDF noise floor is below 10-8/sr in the whole angular range between 8 deg and 170 deg at 1064 nm. We can perform BSDF measurements using incoming light linearly polarised along different axes, and analyse scattered light along independently oriented polarisation axes. The beam spot size on the sample can be varied from about 100 μm up to about 1mm to perform spatially averaged BSDF and TIS measurements. Our laboratory is also equipped with a digital optical microscope and an Atomic Force Microscope providing us with a direct-space characterization of the sample morphology, in order to assist and extend the characterization of samples.

TDS link

17:41 GEO 600 beam splitter Thermal Compensation System: Status and Commissioning

In the GEO600, the beam splitter (BS) experiences a strong thermal lensing effect due to the high power build-up in the Power Recycling Cavity (PRC) combined with a tiny beam waist. This leads to the conversion of the fundamental mode into higher order modes (HOMs), which negatively impacts the detector performance. To overcome this problem, GEO 600 is equipped with a Thermal Compensation System (TCS) applied to the beam splitter. The TCS involves projecting a spatially tunable heating pattern through an optical system onto the beam splitter to correct the thermal lens and bring the detector back to its ideal operating state. This poster aims to discuss the current status and commissioning of the GEO 600 beam splitter thermal compensation system. We will present recent results highlighting the performance achieved, particularly the effect on strain sensitivity, as well as the planned next upgrade to further enhance TCS performance and mitigate power-up challenges.

TDS link

XIV_ET_Symposium_SNadji_GEO600_TCS.pdf

17:42 Advanced Optics Lab @ Tor Vergata for ET (AiLoV-ET)

The AiLoV-ET project seeks to advance optical systems to enhance the performance and quality of the Einstein Telescope (ET) optics. Two primary challenges impacting interferometer sensitivity are high-reflectivity coatings, contributing to thermal noise, and optical aberrations, affecting high-power operation essential for reducing quantum noise. The laboratory at the University of Roma Tor Vergata will explore innovative technologies, particularly in the framework of advanced materials, wave-front sensing, and cryogenic studies. The Aberration control aspect focuses on developing techniques to mitigate optical distortions, by testing new actuators and wave-front sensors and correlating their operation with control and alignment signals. Coatings research emphasizes innovative materials for ET mirror reflective coatings, requiring high optical performance and low mechanical dissipation at both room and cryogenic temperatures. De-icing methods for cryogenic test masses are developed to address frost accumulation, which reduces mirror reflectivity and interferometer stability.
The renovation and adaptation of the infrastructure are presented together with the experimental set up that will be included.

Advanced Optics Lab @ Tor Vergata for ET (AiLoV-ET)

17:43 Techniques for Cryogenic Sensing and Actuation

With increasing sensitivity in the low-frequency region, thermal noise is a growing problem. Cooling the optical parts is one of the essential mitigation techniques, but it has consequences for all components inside the cryostat system. Thus displacement sensors and actuators have to work at the foreseen temperatures below 20 Kelvin. Additionally, they should dissipate as little heat as possible. At cryogenic temperatures, we can use superconductivity to eliminate resistive heating of actuator coils. We present a technique for additive manufacturing of superconductors and their applicability for actuators in gravitational wave detectors. Furthermore, due to changes in the band structure, care has to be taken in the selection of photodiodes and LEDs for cryogenic sensing. We present measurements of the diode behavior at low temperatures.

Speaker: Tim Kuhlbusch (RWTH Aachen University)

TDS

17:44 Superconducting (inertial) sensing and actuation for cryogenic gravitational-wave detectors

Einstein Telescope features a cryogenic design and aims to be sensitive to gravitational waves down to 3 Hz. Methods to apply low-vibration cryogenic cooling of the mirrors in a cryostat to lower thermal noise are currently investigated in research facilities. New (inertial) sensors an such as described here are necessary to monitor the lower cryogenic stages as the application of heat links could introduce spurious vibrations close to the mirror. In addition, heat loads by resistive elements such as coils in coil-magnet actuators can be reduced when using superconducting actuators.

Superconducting (inertial) sensing and actuation for cryogenic gravitational-wave detectors

17:45 A digital filter method to analyze non-linear contributions to the angle-to-length noise coupling

The next generation of gravitational wave detectors is confronted with intricate challenges, highlighting the need for state-of-the-art simulation tools tailored to these emerging complexities. Many of these challenges cannot be accurately modeled with existing frequency-domain tools due to their non-linearities and therefore need to instead be modeled in the time domain. This work develops a method using a digital filter, based on the output of a frequency-domain model with good agreement to the beam spot motion in the Virgo arm cavities, to produce mirror motion in the time-domain and study the non-linear contributions to the angle-to-length noise coupling.

Poster

17:46 Measuring the mechanical and optical losses of coatings by an optomechanical cavity

One of the most critical parts of gravitational wave interferometers are their mirror test masses as coating thermal noise is one of the main limiting factors of the instrumental sensitivity in the frequency band from 20 to 2000 Hz.
Our research work is driven by the aim to study the thermal noise of the highly reflective mirror coatings, indeed new generation gravitational waves detectors, such as Einstein Telescope (ET), are planned to work at 1550 nm or 2100 nm wavelengths and in non-ambient (cryogenic) conditions. New coatings with extremely low absorption and thermal noise are therefore to be developed and it is of paramount importance to evaluate those properties in realistic conditions.
Yet, characterizing both mechanical and optical losses in these coatings presents challenges, particularly at cryogenic temperatures, where thermo-elastic interactions between the coating and the substrate complicate the analysis.
Our study proposes an innovative experimental setup to measure both optical losses and mechanical dissipations in freestanding coating membranes across a wide temperature range. By suspending the coating as a thin membrane, this approach minimizes thermo-elastic interactions and enables precise measurement of the coating's properties in the whole range between room temperature and few Kelvins.
The experimental apparatus includes a low-vibration cryostat inside of which an optical cavity will be installed, together with a set of piezo actuators to precisely control the membrane position and alignment within the cavity field. The measurement consists in placing the membrane inside the resonator so that it couples with the stationary electromagnetic field circulating inside the cavity. The optical losses can be measured by monitoring the finesse of the Fabry- Perot cavity as a function of the membrane position along the optical axis, while the mechanical dissipations will be measured using the cavity as a sensitive transducer of the membrane vibration spectrum and deriving the mechanical dissipations from a suitable data analysis procedure.
Preliminary data from testing low-stress Silicon Nitride (SiN) membranes confirm the functionality of the setup. Future efforts will focus on optimizing the experimental apparatus and expanding the instrumentation for more comprehensive measurements.

TDS link

17:47 Simulation Study of the Sloshing Speedmeter

The low-frequency component of the Einstein telescope is expected to be limited by contributions of seismic, Newtonian and radiation pressure noise. In order to further increase the astrophysical range at these low frequencies, it is essential that all three of these noise sources are reduced simultaneously. This means that, if seismic and Newtonian noise levels see sufficient improvement, one will need to tackle radiation pressure noise. One well-known way of doing this is (frequency-dependent) squeezing. Here, we present a numerical analysis of an alternative, or perhaps complementary solution: The Sloshing speedmeter.

The Sloshing speedmeter extends on the standard Michelson interferometer with an additional filter cavity at the dark port. In particular, we are interested in the capabilities to control this extra cavity, as the response of the speedmeter drops quickly at lower frequencies. Furthermore, we can put limits on the requirements for the cavity suspensions.

A speedmeter is a powerful option to explore in combination with squeezing, as it allows to probe below the standard quantum limit for frequencies below the first cavity pole and it eliminates the need for frequency dependent squeezing. On top of that, the noise-mitigation effect increases linearly with decreasing frequency, which can lead to a factor 100 improvement in quantum-noise limited sensitivity in the frequency range of interest for ET-LF.

17:48 White Rabbit FMC mezzanine as an interface for the new 10G WR-NIC to remote WR DAQ nodes

The White Rabbit protocol (WR), developed at CERN for the distribution of sub-nanosecond timing to thousands of nodes distributed over large geographic areas, is becoming increasingly reliable and used in many contexts, especially in the modern landscape of multi-messenger astronomy experiments in progress such as KM3NeT, CTAO and of course ET.

Currently, the White Rabbit switch is basically the only equipment designed with wide usability by the user community in mind. At the present time, WR implements connectivity with 1 Gb/s Ethernet, both point-to-point 1GB and through WR-switches. WR-switch represents only the timing distribution layer, while the compatible consumer products for data acquisition are mostly proprietary development for specific applications. Fortunately, the WR community is already conceiving new developments toward a full 10 GB/s infrastructure where a new PCIe NIC board is foreseen to connect PCs to the WR network.

INFN-Bologna and INFN-Perugia are designing a set of low-cost electronic boards that allow a versatile management and readout of the most common sensors or actuators using White Rabbit technology for the time-synchronization. We propose a lightweight dedicated mezzanine board, named Air-Plane, to equip the upcoming new NIC board in order to interface between legacy WR-node as well as with non-WR remote cards. Such a modular and highly scalable design will ease the implementation of data acquisition systems in testing situations, e.g. ET mirror suspensions developments.

In this contribution we present the Air-Plane conceptual design and its potential use. A realization plan exists as a task of the M2TECH project, whose proposal has been recently submitted to the HORIZON-INFRA-2024-TECH-01-01 call and it will be presented in this contribution as well.

link to ET TDS ET-0138A-24

17:49 Cryogenic interferometric inertial sensors for penultimate mirror residual vibration monitoring

The poster aims to present highly sensitive inertial sensors developed for future gravitational-wave detectors. E-TEST (Einstein Telescope Euregio Meuse-Rhine Site & Technology)[1,2] is an international collaboration that consists of a prototype suspension combining passive and active isolation techniques for a 100 kg silicon mirror cooled down radiatively to 25 K in a suspended cryostat. It is aimed at validating R&D to meet Einstein Telescope’s requirements in the relevant environment [3]. This unprecedented seismic isolation calls for highly sensitive inertial sensors at each stage of the isolation chain to monitor its efficiency, as well as the performance of the low-vibration cooling strategy by characterizing the residual motion at the mirror level. Several sensors have been developed either as part of the isolation stage of the suspension or as witness sensors in the harsh cryogenic environment close to the mirror. Cryogenic and vacuum compatible horizontal and vertical cryogenic inertial sensors were developed to monitor the cryogenic penultimate stage down to 1 fm/√Hz from 1 Hz onwards.
[1] A. Sider, C. D. Fronzo, L. Amez-Droz, A. Amorosi, F. Badaracco, P. Baer, A. Bertolini, G. Bruno, P. Cebeci, C. Collette, et al., Classical and Quantum Gravity 40, 165002 (2023), URL https://dx.doi.org/10.1088/1361-6382/ace230
[2] A. Sider, L. Amez-Droz, A. Amorosi, F. Badaracco, P. Baer, G. Bruno, A. Bertolini, C. Collette, P. Cebeci, C. D. Fronzo, et al., E-test prototype design report (2022), 2212.10083.
[3] S. Di Pace, V. Mangano, L. Pierini, A. Rezaei, J.-S. Hennig, M. Hennig, D. Pascucci, A. Allocca, I. Tosta e Melo, V. G. Nair, et al., Galaxies 10 (2022), ISSN 2075-4434, URL https://doi.org/10.3390/galaxies10030065

TDS link ET-0223A-24

Zeoli - ET symposium poster 2024.pdf

17:50 High resolution optical accelerometers for active vibration isolation in ETEST

The talk aims to present the design and performance of high-resolution inertial sensors/accelerometers. The sensors are built around a novel interferometric readout technique, allowing to reach sub-pm resolution. These sensors have been employed in the E-TEST project, which have been demonstrating, amongst others, a novel active-passive strategy for isolating the test-mass of the ET. They have been used both as witness sensors for monitoring the residual motion of the payload with high accuracy, and as in-loop sensors in the active vibration compensation system. The sensors have been designed to be compatible with the high-vacuum environment found in most advanced gravitational wave detectors. The witness sensor is also designed for use at cryogenic temperature of 20K, which has been reached in ETEST.

Speaker: Anthony Amorosi (Université de Liège)

AMOROSI_ETSymposium2024.pdf

17:51 The Magnetic Dipole Model

The Gravitational Waves (GWs) interferometers are very big facilities and
the choice of the material to build their arms is crucial within the scope of the
project.
The second generation (2G) of GWs antennas have been built using austenitic
stainless steel like 304L (LIGO, Virgo, KAGRA) and 316L (GEO600), which
are no magnetic materials. However, the third-generation (3G) detectors, being
larger and more sensitive than their predecessors, may find cost-prohibitive the
use of these steels.
Einstein Telescope (ET) is a third-generation GWs antenna, which present de-
sign foresees six interferometers with 10 km arms (“xylophone” configuration)
but also a “2L-shape” configuration formed by interferometers with 15 km arms
is being discussed. For ET, the use of ferritic steel for the pipes is being explored
as a more cost-effective alternative than an austenitic solution.
However, the residual magnetization of ferritic steels should be considered as a
potential source of noise that could affect the ET sensitivity curve.
This study aims to present a model, named the Magnetic Dipole Model, which
predicts how a ferritic tube impacts the sensitivity curve of a given instru-
ment, using actual seismic noise data. The model primarily uses data from Sos
enattos, more precisely the 90th percentile from the north-south channel of a
seismometer (HHN instrument), and a key magnetic parameter like the coer-
cive force (Fc). The model has been supported by the characterisation of three
different ferritic steels samples (AISI 430, 444 and 441). The whole process was
carried-out in collaboration with CERN, using the split-coil permeameter for
the measurements of the coercive force.
Our model indicates that the primary contribution of magnetic noise from the
tested ferritic materials occurs between 1 and 2 Hz. It is critical to highlight
also that the model is very sensitive to the distance “d” between the tube and
the mirror, correlating to the length of the cryotrap.
According to the model, the magnetic noise contribution from the tube results to be five orders of magnitude lower than the ET sensitivity. Although this model
has numerous potential enhancements, two notable improvements include in-
corporating seismic data from different potential sites and updating the model
to account for the “2L-shape” configuration.

The Magnetic Dipole Model Poster (P#22)

17:52 DESIGN AND ANALYSIS OF THE CRYSTALLINE SILICON TRIANGULAR VERTICAL SPRING BLADES - CRYOGENICS SUSPENSION SYSTEM

Gravitational wave detectors, such as the Einstein Telescope (ET), rely on optimized cryogenics suspension systems to enhance detection sensitivity. In this study, we address the optimization of crystalline silicon triangular blades within the ET's cryogenics suspension system. Our purpose is to reduce the natural frequency while maintaining surface tensile stress below 90 MPa, crucial for optimal performance. Leveraging simulation techniques in ANSYS, we systematically adjust critical parameters, including length, width, and thickness, to optimize blade performance. Through exploration of different design options, with applied forces of 50kg and 100kg, we evaluate their impact on vertical axis deformation and von Mises stress distribution on the blade surface. Additionally, we study the correlation between von Mises stress distribution and crystalline orientations, providing insights into structural behavior. Assembly considerations within the cryogenics suspension system are also addressed, recognizing the importance of design parameters and assembly processes. Furthermore, experimental determination of the breaking strength of wire electrical discharge machining (WEDM) silicon samples offers further insights into crystalline silicon axis behavior, contributing to the refinement of blade designs for optimal suspension system performance.

poster

17:53 A Database for data management of superattenuator construction for GW detectors

Data management and storage is of paramount importance in experimental activities to track progress, ensure accuracy and reproducibility of the results. Relational databases offer a reliable solution for keeping track of large amounts of data, media and information related to any components and tools which are present in a physics laboratory. In this talk, we present the database infrastructure we have developed for data management of experimental activities in the Virgo-ET group in Pisa. This infrastructure is now operative and running and is a useful tool to track components and measures for suspensions prototypes such as those planned for ET.

Speaker: Michele Vacatello

TDS Link

17:54 Ultra-thin Nanolayers Coatings for gravitational wave detector

To improve the sensitivity of laser interferometric gravitational wave detectors, the reduction of noise sources is of great importance. A primary noise source, which is dominant in the 20-300 Hz band, is thermal noise from the coatings deposited on the terminal masses. Currently, these coatings consist of alternating layers of low- and high- index materials, SiO2 and TiO2-doped Ta2O5 respectively, in the amorphous phase. These materials are not suitable for the coatings of cryogenic 3rd-generation gravitational wave interferometric detectors because they suffer from large mechanical losses at cryogenic temperatures. In this work, a new strategy to replace TiO2-doped Ta2O5, with nanostratified structures composed of alternating layers of SiO2 and TiO2, was proposed. As it has been modeled that this nanostructure has excellent properties in terms of mechanical losses at cryogenic temperatures and withstands high annealing temperatures without crystallizing. The SiO2/TiO2 prototype was deposited by plasma- assisted electron beam deposition. The composite consists of 38 TiO2 layers, each with a nominal thickness of 2.0 nm, and 38 SiO2 layers, each with a nominal thickness of 1.3 nm, for a total of 76 nanolayers and a total thickness of 125.4 nm. Structural, morphological, and optical properties of the as-deposited and annealed 76-nanolayer sample were explored by using Atomic Force Microscopy, X-Ray Reflectivity, Raman Spectroscopy and Spectroscopic Ellipsometry. In addition, a section analysis of the sample was performed by means of Scanning Transmission Electron Microscopy. By performing morphological analysis, a high uniformity of coverage and remarkable surface flatness was demonstrated. It was remarkable demonstrated that the amorphous phase is preserved upon annealing. Loss angle measurements are in progress at room temperature and the first results are very interesting.

Ultra-thin Nanolayers Coatings for gravitational wave detector

17:55 Deep Learning Based Real-Time Noise Mitigation

Mitigation techniques for Newtonian noise are essential due to the increasing sensitivity of future earth-based gravitational wave detectors. We are exploring deep learning as a model-independent technique to predict seismic-induced variations of the interferometer strain. Compared to conventional Wiener filters, convolutional neural networks can learn to distinguish a multiplicity of patterns and adapt to variations in the signal-to-noise ratio. Evaluating these networks on Field Programmable Gate Arrays (FPGAs) enables real-time prediction with high throughput and stable timing. We present a toolchain for optimizing the architecture of a quantized neural network to utilize the FPGA resources efficiently. In our lab setup, the network has outperformed a Wiener filter in canceling mechanically coupled vibrations in a small interferometer.

Speakers: Markus Bachlechner (RWTH Aachen University), Tim Kuhlbusch (RWTH Aachen University)

TDS

17:56 Demonstrating up to 20 dB of straylight suppression with tunable coherence

As straylight is a dominating limitation for the sensitivity of gravitational wave detectors, we investigate new laser operation concepts and interferometer topologies for a more straylight-resilient detector configuration.
Our main focus is the use of tunable coherence realized by phase modulation following a pseudo-random-sequence on the interferometer laser.
This breaks the coherence of the delayed straylight reducing its intrusive impact with the remaining coherence length only depending on the modulation frequency. Thus, effectively realizing a pseudo white-light interferometer with tunable coherence length. We demonstrate this in a Michelson-topology with a remaining coherence length of roughly 30 cm and prepare to experimentally adapt it for cavities and Sagnac-like interferometers.
Here, we present our recent results, achieving close to 20 dB of straylight suppression in a table top Michelson-interferometer using tunable coherence.

Speaker: Daniel Voigt (Universität Hamburg)

17:57 Mitigation of non-axisymmetric optical defects for the future gravitational wave detectors

The experience gained during the commissioning of Advanced Virgo (AdV) has clearly highlighted the necessity of monitoring and controlling optical aberrations in a gravitational wave interferometric detector. The Thermal Compensation system (TCS), designed to detect and compensate aberrations caused by limits in the optics production process or laser power absorption in coatings, has made possible the operation of AdV in O3. TCS exploits thermo-optic effect to correct for wavefront deformations by illuminating on-path optics with a shaped CO2 laser beam. With the foreseen high-power operation of ET-HF, the likely need of an adaptive control of residual aberrations in optical cavities has triggered a phase of conceptualization and prototyping of new actuators. This class of actuators must be versatile and ideally introduce no frequency-dependent noise in the detector band. We are presently exploring the application of deformable mirrors (DMs) as a versatile solution to project non-axisymmetric intensity patterns. DMs feature an intrinsic capacity for adaptive corrections and immunity to frequency-dependent noise due to their static nature. We developed a Modified Gerchberg-Saxton (MoG-S) algorithm to retrieve the phase correction needed to a particular intensity pattern on the image plane. The MoG-S simulations of an on-bench DM-based system and the results of the experimental tests will be presented.

Mitigation of non-axisymmetric optical defects for the future gravitational wave detectors

17:59 High Precision, Compact Inertial Sensors

ET's ambitious targets for low-frequency sensitivity require outstanding performance from its seismic isolation. A vital element of this will be the inertial sensors used to monitor ground motion and inform active control isolation schemes. Current inertial sensors used in LIGO are bulky, not vacuum-compatible, and unsuitable for cryogenic environments. Therefore, we aim to design inertial sensors better suited for next-generation gravitational wave detectors. However, reducing the size of inertial sensors requires careful design to avoid sacrificing the noise performance of the devices. These sensors use small, fused silica mechanical oscillators and interferometric readouts to achieve comparable performance to bulkier inertial sensors in a smaller, vacuum-compatible package. We will present the key results of two recent papers, one on the sensors' design and one on prototype sensors' results. The measurements shows ~ng/sqrt(Hz) performance in a broad band from 0.1-100Hz, with lower noise floors being theoretically possible, making their performance comparable to some of the best sensors today. The prototype design can easily be altered to meet ET's specific isolation requirements. With this talk, we will increase awareness in the community of these sensors and their usefulness as we design the seismic isolation strategy of ET.

TDS link

18:00 Real-Time Control System: Improving Low Frequency Performance

Drawing upon insights from the VIRGO project, this study focuses on the development of an advanced Real-Time Control System (RCS) tailored for the precise feedback control of suspended optical devices and seismic isolation systems. We provide an overview of the project's status, highlighting the use of standard communication protocols, Field-Programmable Gate Arrays (FPGAs), and Digital Signal Processors (DSPs). In this work, we propose enhancements aimed at boosting performance in the low frequency range.

Specifically, we address the challenge of Digital-to-Analog Converters (DACs) exhibiting suboptimal low frequency performance due to voltage reference noise. Our investigation explores cutting-edge DACs sourced from the high-end audio domain, renowned for their remarkable total harmonic distortion (THD) and signal-to-noise ratio (SNR) characteristics, which hold promise for elevating system performance.

Moreover, we discuss the selection of Analog-to-Digital Converters (ADCs) optimized for compatibility with modulated sensors, a crucial consideration often overlooked in gravitational wave detectors. Enhanced low frequency ADCs are indispensable for applications such as the DC readout of optical levers used for position measurement of suspended optics in respect with the local reference frame, or for monitoring low frequency currents in magnet-coil actuators.

By integrating these advancements, we aim to improve the low frequency capabilities of the real-time control system.

TDS link

18:01 DAQ and time synchronisation in the INFN-Bologna group

The INFN-Bologna group with interests in the ISB activities is kin on DAQ (electronics and online software) and time synchronization with the White Rabbit technology. We have consolidated our expertises through decades of work in High Energy Particle and Astroparticle Physics experiments at LHC and underwater neutrino telescopes. In this contribution we will present our assets that could be exploited for Einstein Telescope. In particular our group has been funded with the ETIC project to realize a facility which includes readout, fast data processing, time synchronization and higher level data analysis, called Bologna ET Integrated Facility (BETIF). BETIF is in synergy with other ETIC activities, in particular with the CAOS laboratory which represents an optimal concrete use-case for developing technologies useful in ET.

ET-0183A-24 - DAQ and time synchronisation in the INFN-Bologna group

18:02 The Superatenuator for seismic noise suppression of the CAOS Project

The Superatenuator is the mechanical structure conceived to suppress the transmission of seismic noise at the level of the optical components in the Advanced VIRGO laser interferometer. Thanks to the experience acquired in the development and construction of this complex structure, the INFN Pisa group is designing, in collaboration with INFN Perugia group, a filtering system based on the Superatenuator technology. The new generation system is being revised to improve the passive atenuation performance extending the detection band in the low frequency region (around 2-3 Hz) in view of the Einstein Telescope Interferometer. At the University of Perugia the CAOS facility is a very promising experimental site to test a full scale suspension system to validate a new Superatenuator, about 15 m high, as reference solution for ET Interferometer.

18:03 New data on geological investigations at Einstein Telescope site of Sardinia (Italy)

In the framework of the SAR-GRAV and FdS-2021 projects, new investigations in the area comprised within the potential vertexes (Bitti-Lula-Mamone) limiting the ET triangle have been performed with the aim to assess the geological, structural and neotectonic, and hydrogeological conditions. For this purpose, we adopted a multidisciplinary approach involving detailed structural, geological and petrological investigations, and groundwater sampling and analysis (both water chemistry and stable isotopes δD, δ17O and δ18O).
Compared to the maps published so far, new field data show a more complex geological setting of the study area, characterized by a higher variability of the outcropping lithologies, including for example a recurring interlayering of gneiss and mica-schist, and the presence of granite veins of variable thickness from a few to tens of meters, never mapped until now. The main structural features are the SE-dipping schistosity affecting the metamorphic rocks of the Variscan basement, and strike-slip faults with a predominantly NE-SW orientation, often paired with granite veins. Preliminary petrological data confirm previous works, and will be supported by new P-T-t estimates in the near future. Geological structures strongly control geometry of aquifers and groundwater potential in the area. Chemistry of groundwater, in agreement with the lithologies of aquifers, varied from Cl-Na compositions to Ca-Mg-bicarbonates, in some samples, the concentration of trace elements (Al, Fe, Mn) become relevant. Stable isotope of groundwater lay close to the SIMWL (South Italian Meteoric Water Line) indicating a meteoric origin of water, whereas evidence of fractionation processes was not detected.
All data collected has been organised in a shared database through GIS platform. These preliminary results will be the base to implement a 3D geological model of the area and assess the underground fluid circulation.

P#34.pdf

18:05 Towards numerical models for seismic and Newtonian noise due to anthropogenic sources

Anthropogenic or human-induced noise sources such as road or railway traffic, wind turbines, and mining or industrial activities generate ground vibration in a frequency range between 1 and 80 Hz (depending on the source type). The impact of this seismic noise on the operation of the Einstein Telescope can be reduced by hanging the mirrors in suspension towers. However, waves propagating in the soil also generate density fluctuations leading to seismic Newtonian noise (NN), which cannot be shielded and is an important noise component between 1 and 10 Hz.

We aim to develop numerical models for the prediction of ground-borne vibration due to several anthropogenic noise sources. Our first focus is on railway traffic, as multiple freight and high-speed lines pass through the Euregio Meuse-Rhine (EMR). We predict vibration levels due to train passages at several distances from the track, both at the free surface and at depth. The analysis is performed for passenger, freight and high-speed trains.

In a second step, a numerical model for the prediction of seismic NN is developed. The soil domain surrounding the cavity containing the test mass is discretized with finite elements (FE). The incoming wavefield generated by the train passages is imposed as Dirichlet boundary conditions at the edges of the FE mesh, and the scattered wavefield due to the presence of the cavity is computed. Subsequently, the NN caused by the scattered wavefield is computed using the Gaussian quadrature rule. The model is validated by predicting NN due to plane P- and S-waves propagating in a homogeneous medium, for which analytical expressions are available. Since an FE mesh is used, the model offers flexibility in terms of size or shape of the cavity and of soil heterogeneity.

poster35.pdf

18:06 Estimating the Detection Horizon for Core-Collapse Supernovae

Core-collapse supernovae are one of the most anticipated gravitational wave sources in the frequency band of the Einstein Telescope (ET). A detection of such an event can provide crucial information on the processes occurring during the final stages of massive stars and open perspectives in multi-messenger astronomy. Compared to current detectors, capable of measuring supernovae within a fraction of our galaxy, the improved sensitivity of ET will significantly increase the observable volume and, therefore, the expected event rate.
Likelihood-based matched filtering gives an upper-limit estimate of the detection horizon for core-collapse supernovae. However, due to the highly stochastic nature of the core-collapse process, matched filtering is not applicable in burst searches. Thus, non-template-dependent methods are additionally investigated.

Speaker: Mr Timo Butz (RWTH Aachen University)

Estimating the Detection Horizon for Core-Collapse Supernovae

18:07 Exploring Neutrino-GW Correlations: Navigating Challenges Envisioning the ET Era

In this era of multi-messenger astronomy, we have been able to detect common sources of gravitational waves (GW) and photons. However, there is still a missing correlation between GW and neutrino sources. The scenarios involving binary mergers have been particularly favoured for a long time. However, no evidence has been found yet. The aim of our research is to contribute to this aspect. We are looking into the sub-threshold GW candidate selections from the LIGO-Virgo-KAGRA collaboration, and searching for sub-TeV neutrino counterparts using IceCube data. This improves our understanding about the threshold for GW detection. This might also improve the significance and localisation of the sub-threshold GW candidates. We report on the current status of the ongoing work. In addition, we will adapt our analysis techniques involving the next generation GW and neutrino detectors. The Einstein Telescope (ET) will have significantly improved sensitivity for high- and low frequency GW, a better sky localisation and a larger distance horizon. As a result of that, it will detect 100s of BNS events per day, which will need to be followed up with neutrinos. However, we are yet to identify the analysis pipelines and data brokers which will help us to follow up such a huge number of GW candidates within a short time window in real-time. Therefore, the motivation of this work is also to identify prospective solutions so that we are prepared as we enter the ET era.

ET@Maastricht_poster2024.pdf

Exploring neutrino-GW correlation: Navigating challenges envisioning the ET era

18:08 The luminosity of the darkness - Schechter function in cosmological analysis with dark sirens

The gravitational-wave (GW) cosmology community has been developing techniques and methodologies to infer the cosmological parameters and investigate the black hole population with Compact Binary Coalescences (CBCs) without an electromagnetic counterpart, commonly referred to as dark sirens.

In this study, our focus lies on the method based on galaxy catalogues such as GLADE+, a composite catalogue whose completeness varies across the sky. Galaxy catalogues typically suffer from significant incompleteness after redshift z = 0.1. To date, most of the sources of GW detections have originated from larger distances, and with ET this trend is destined to continue, potentially extending detection capabilities to redshift as high as z = 10.

Hence, to infer cosmological parameters with a Python package such as gwcosmo, it is necessary to estimate the luminosity of galaxies beyond the detection threshold of electromagnetic telescopes – “ the luminosity of the darkness”. This estimation currently relies on the Schechter function. Empirical evidence points towards an evolution of the Schechter function as a function of the redshift, however, this effect is not yet accounted for in the cosmological analysis. We will show how the redshift dependency can impact the line of sight(LOS) redshift prior and subsequently the posterior distribution of H0 due to the evolving Schechter function.

link to TDS

18:09 Preliminary CFD analysis of the airflow inside base tower

Preserving the cleanliness of the main optics during installation and maintenance in the tower is a critical objective in ET. This requirement has an impact on the design of the clean air injection paths, which should aim to minimize the contamination induced by the operator working in the tower and prevent the transport of contaminating particles from unclean areas to the critical optical surfaces.
In order to predict the air fluxes inside the tower, a preliminary CFD (Computational Fluid Dynamics) analysis was carried out in a VIRGO-like base tower chamber. This paper shows the process of a CFD analysis starting from the simplification of the geometry and the meshing of the volume domain. Different scenarios of air inflow and outflow are compared in terms of mass flow rates and outflow boundaries. The proposed study will be a useful tool for the design of ET towers.

Preliminary CFD analysis of the airflow inside base tower

18:10 Modal analysis of a new possible ET base tower lay out

The mechanical transfer function of the ET towers basement plays a crucial role on the response of the Super-Attenuator (SA), on the stability of the ET suspension and in general on the low frequency performance of ET. For this reason, it is of pivotal importance to investigate the behavior of the ET tower – basement system with a Finite Element modelling technique. Particular emphasis has been placed on the tower basement, investigating a new conical design. A new test facility, CAOS, is under realization in Perugia within the PNRR-ETIC framework, aiming to test mechanical solutions for ET. Two new towers will actually be realized shortly and will be an useful tool to provide feedback on: mechanical performance, construction and economic aspects, functionality of all details and real-scale operational experience with vacuum and payloads.

ET-0167A-24

Poster_Capoccia.pdf

18:11 ET test masses parameter estimations through Virtual Mirror Maps.

"The sensitivity goal of the Einstein Telescope is to achieve a minimum of tenfold improvement over second-generation interferometers, transitioning from Z=2 to Z=100. Attaining this precision requires meticulous attention to parameter specifications for the Test Masses.Beam distortions and light scattering significantly influence signal quality, requiring detailed information on surface specifications.

While substrate material and mirror size have already been determined, close-up details about surface specifications are now crucial. In our efforts, we take the initial steps in this direction. Utilizing a blend of Zernike basis and PSD (Power Spectral Density) analyses, we generate a set of Virtual Mirror maps. These maps provide robust statistical insights into the mirror requirements.

By assessing the performance of these virtual optics through simulations, we can predict the modal content of the beam and tailor mirror surface parameters to achieve the desired sensitivity. We construct these virtual maps using surface data from Advanced LIGO and Advanced Virgo, providing a realistic reference point for our research.
Our work address the ability pf well-known mathematical tools to generate realistic mirror surfaces and assesses the performance of virtual mirrors to align with the ambitious goals of the Einstein Telescope."

poster_ET_symp.pdf

18:12 Developments towards the cryogenic helium infrastructure for ET

Cryogenic operation of ET-LF is imperative for exploiting the full scientific potential of ET, with test masses operated at temperatures of 10 K to 20 K in order to suppress the suspension thermal noise to the level of Newtonian noise. Moreover, large cryopumps are required to uphold sufficient vacuum quality in both ET-LF and ET-HF.
A concept for a helium-based cryogenic infrastructure capable of providing cooling power to all respective consumers in ET has been presented and published.
With this contribution, we provide an update on the infrastructure development, outlining estimations of basic operation parameters (cooling power, power input) as well as estimated dimensions of main components.

Link to TDS-entry

18:13 Alternative Concepts for the Ultra-High Vacuum Tubes

The Einstein Telescope requires about 120 km of vacuum tubes with a diameter of 1 m to achieve the design sensitivity and reduce scattered light.
The pressure inside the tubes needs to be below 10$^{-11}$ mbar to minimize the residual gas noise.
The current baseline concept of the vacuum system foresees passive sections welded together from stainless steel and connected to pumping stations.
Achieving ultra-high vacuum (UHV) in these tubes requires high pumping capacities and long bake-out times of the tubes, which is associated with high energy and equipment costs.
This poster discusses different improvements over the baseline design, like integrating getter surfaces into the inside of the tubes promising a cheaper and more homogeneous distribution of pumping power.
Furthermore, we will give an overview of the development and establishment of laser beam welding under vacuum as a new technology to produce UHV as it requires less effort to rework the weld seams.
Forming the flanges of the pipe material itself to ensure a seamless flange connection is another concept that is present in this poster.

Speaker: Ms Charlotte Benning (RWTH Aachen University)

Alternative Concept for the Ultra-High Vacuum Tubes

18:14 First measurements for test and characterization of the Pendulum Inverted Pendulum for ET suspensions

One of the goals of the Einstein Telescope is to improve the sensitivity at low frequencies. This target enables us to look gravitational waves carrying information from the early Universe, extend the time observation of binary system of compact objects, and enhancing the signal-to-noise ratio for spinning neutron stars and stochastic background.
The Einstein Telescope aims at reaching a sensitivity of approximately 10−22 Hz−1/2 at 2 Hz, more than ten times better the sensitivity of Virgo and LIGO interferometers. This can be obteined with a Super-Attenuator (SA) that is 17 meters long or, alternatively, with a new design that reduces the height of the SA. Moreover the narrow restricted mine tunnels at SOS Enattos require a more compact solution for the super attenuator. Inside the project “ Black Holes for ET in Sardinia”(BHETSA) a new concept of filter has been developed: the Pendulum Inverted Pendulum (PIP). With the term PIP we mean a single stadium of a multi-stage pendulum capable of attenuating both vertical and horizontal vibrations.
With the term PIP it means a single stadium of a multi-stage pendulum capable of attenuating both vertical and horizontal vibrations. In this new design the super attenuator is made up of a chain of PIP: two stages of PIP can achieve an attenuation of ∼ 10−4 and three stages can attenuate to approximately 10−5. Moreover the small dimensions of a single PIP allow us to connect three of them within a span of 4 meters.
At the ET laboratory in Pisa we have begun assembling and studying the first prototype of PIP. Initial measurements have been collected, and we are currently working on studying the horizontal vibrations. At the ET Symposium we will present the first measurements of the PIP filter: in this first step we characterized the PIP and studied the behavior of the filter in various configurations.

First_test_and_measurements_on_Pendulum_Inverted_Pendulum_Poster.pdf

18:15 All-polarisation beamsplitters for advanced quantum noise mitigation schemes

The design sensitivity of future gravitational-wave detectors like Einstein Telescope is fundamentally limited by quantum noise over a wide frequency range. Speedmeters can overcome this semi-classical sensitivity limit, because they probe a quantum non-demolition observable. Polarisation-based speedmeters are a class of speedmeters that do not require large infrastructure changes compared to current detector topologies and are therefore favourable for potential detector upgrades. However, they do require the main interferometer to be controlled for two orthogonal polarisations of light at the same time. Here, we investigate properties of beamsplitter samples with all-polarisation coatings, i.e. 50/50 beamsplitters that are designed to perform for both orthogonal polarisations of light at the same time. We specifically investigate the phase shift that the central beamsplitter introduces between p-polarised and s-polarised light at the dark port of the Michelson interferometer configuration. We use different analysis methods, including correlation and ellipse fitting, to extract the phase from the data of a scanning Michelson table-top experiment. We also present a method to calculate the effect of this dark fringe offset on the quantum-noise limited sensitivity of a polarisation-circulation speedmeter.

All-polarisation beamsplitters for advanced quantum noise mitigation schemes

18:16 Advancements in Rasnik readout

The Rasnik is originally a 3-point alignment system under continuous development since 1993 where it was first used to align the muon chambers of the ATLAS experiment at CERN.
A light source illuminates a special mask which is projected on a CMOS sensor using an objective/lens. This image of the mask is analyzed to calculate the absolute position. This allows us to find displacements on the axes which are perpendicular to the optical axis without any coupling between them, with the same noise floor in all frequencies. Any motion of the mask, objective or pixel sensor is picked up as image motion. In the recent years, the advancement has allowed the spatial resolution down to 7 pm/√Hz. These features can be exploited for the future GW detectors where isolated optical benches can be interlocked to reduce the differential motion between them in degrees of freedom inaccessible to other sensing solutions.

Advancements in Rasnik readout (ET-0157A-24) (TDS Link)

Advancements in Rasnik readout (PDF)

18:17 Metallurgical aspects of the ET beampipe design

Laser beams of the Einstein Telescope (ET) are currently planned to be contained in a 120 km-long 1 m-diameter ultra-high vacuum pipeline, which intends to become the largest ultra-high vacuum system ever built. Traditionally, austenitic stainless steel is used for such pipelines, but given the scale of the project, alternative materials must be considered to reduce the cost. Ferritic stainless steel (FSS) is a good alternative but presents challenges when it comes to welding. An overview of a joint research program between Ghent University and CERN is presented in this contribution. The work included modelling of weld heating cycles, microstructure characterization, and failure analysis. Microstructural features and their effects on the weld zone formability in several FSS grades are discussed, and preliminary conclusions concerning FSS applicability in the ET project are drawn.

Metallurgical aspects of the ET beampipe design

18:18 Comparing Topologies of the Einstein Telescope: Advancing Sky Localization and Detector Calibration in Third-Generation Gravitational Wave Detectors

Third-generation gravitational wave detectors like the Einstein Telescope and Cosmic Explorer will have better sensitivity than current ones. The triangular setup is proposed to have three detectors forming an equilateral triangle. Although whether the Einstein Telescope should follow an L-shape or triangular topology has arisen from time to time. Choosing between them is crucial for finalizing its design. This study compares how these setups affect finding where in the sky the gravitational waves come from. The L-shape will have 90-degree angles. We consider the performance of the Einstein Telescope in the network of two Cosmic Explorer detectors. The results show that the ET with triangular topology has better sky localization accuracy compared to the ET as an L-shape detector. The triangular setup has an extra advantage: it can create a "null stream" regardless of where the waves come from. This feature makes it stand out and can help calibrate the detectors better. We have used the residual signal to nullify the stream, and the results show that if the ET can detect a large number (> 100) of loud events more frequently, or within a time span when the detector response function remains the same, it can be used to calibrate the detector with good precision (<0.5% error in calibration parameter).

ET_symposium_presn_AS-3.pdf

TDS link for ET-0192A-24

18:00 → 19:00 Executive Board

Wednesday, 8 May

09:00 → 10:45 EIB

Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco

Zoom Room 2.18

09:00 ETO discussion

Speaker: Achim Stahl (RWTH Aachen University)

09:30 MDC coordination and info gathering

Speakers: Andres Tanasijczuk (Universite catholique de Louvain), Gonzalo Merino, Stefano Bagnasco

Markus Bachlechner ET-0273A-24_ComputationalRequirementsOfMac.pdf

10:00 OSCARS proposals

Slides in TDS

09:00 → 10:45 ISB: Contributed Talks

Conveners: Jan Harms, Stefan Hild

ET-Symposium Room 2.2

09:00 Instrument Science update from Glasgow Group

The Institute for Gravitational Research Einstein Telescope research unit at the University of Glasgow is actively investigating many topics of instrument science related to the Einstein Telescope. We are working towards experimental demonstrations and proof of concept demonstrations of suspensions systems for the high and low frequency detectors, substrate and coatings characterisation and development, and commissioning of a cryogenic interferometer prototype. This talk will be an update on these research lines and progress towards the Einstein Telescope.

Instrument Science update from Glasgow Group: ET Symposium 2024 Maastricht

TIGRETSympossium2024.pdf

09:20 Updated study of scattered light and baffle design in the main arms of the Einstein Telescope gravitational wave detector

We present an updated estimation of the noise induced by scattered light inside the main arms of the Einstein Telescope (ET) gravitational wave detector. Both ET configurations for high- and low-frequency interferometers are considered, for which we propose baffle layouts and designs. The noise estimations are done using both numerical tools and analytical formulas. For the baseline configuration and nominal operations, we conclude that the scattered light noise can be maintained at acceptable levels such that it does not compromise the ET performance, provided some requirements are met. We additionally simulate the effect of the presence of a beam misalignment, of point defects and an off-axis beam, recasting the results into upper limits of these non-idealities of the cavity. We also show a first study of baffle vibrations, concluding that the resonances of the mechanical coupling with the tube do not compromise the scattered light noise.

TDS link

09:40 Strain noise induced by dust contamination in ET and cleanliness requirements

Dust particles present inside the Einstein Telescope vacuum pipes can be a possible source of scattered light. It is therefore important to accurately model the light-dust interaction mechanisms and the noise they can generate, so as to be able to put constraints on the maximum allowed population of particles in the vacuum pipes. It is also important to identify the processes/events that may introduce particles inside the vacuum pipes, as well as understand how the population of particles that can interact with the laser beam changes during the lifetime of ET.

In this work, we study two possible occurrences of light-dust interaction: one with dust deposited on baffles and the other with particles moving in space. Particle contamination of the baffles worsen the scattering properties of their surfaces, while particles moving in space cross the beam and scattering light. We briefly summarize the results obtained for dust deposited on baffles and report our advances on sizing the stray light noise contributed by moving particles. For this latter contribution we have developed an original method to quantify the strain noise induced by particles detaching from the tube.

From our results we study how installation procedures and general operations on beam-pipes can contribute in terms of dust contamination. This allows us to place upper limits on the dust particles (number and size) that we can tolerate inside the pipe and hence set constraints on the cleanliness of environments and installation procedures.

TDS link

10:00 Potential of Seismic and Newtonian Noise Suppression in ET using distributed fiber sensors

Newtonian noise significantly impacts the Einstein Telescope’s low-frequency performance. To address this, one approach is to use large sensor arrays to capture the seismic field, estimate test mass acceleration, and subsequently adjust the gravitational wave data during post-processing. Fiber sensors are becoming a practical technology to the challenges of large seismic sensor networks because they can sense seismic movements all along their length.

Our research, conducted at the science campus in Hamburg Bahrenfeld in collaboration with the WAVE initiative, explores the capabilities and limitations of current distributed acoustic sensing (DAS) technology using fiber sensors. This includes assessing how these systems can be effectively employed for seismic and Newtonian noise suppression in ET. In this presentation, we will share the latest findings from the WAVE network, mainly focusing on the low-frequency performance of DAS systems and the potential enhancements achievable through fiber sensors that are read out using digitally-enhanced interferometry.
Additionally, we will show the status and results from our simulations on reducing Newtonian noise using distributed strainmeters. We'll look at how a network of strainmeters, explicitly designed around ET's test masses, performs in comparison to a seismometer network.

TDS Link

10:20 Virgo's Quantum Noise Reduction System: Current Status and Future Insights

Quantum noise poses a fundamental limitation to the sensitivity of second-generation terrestrial gravitational wave detectors,affecting both low and high frequencies through radiation pressure noise and shot noise, respectively. Overcoming this challenge is crucial for advancing to third-generation detectors such as the Einstein Telescope.

Since the third observation run (O3), both LIGO and Virgo implemented a quantum noise reduction system. By employing a Frequency Independent Squeezing (FIS) vacuum source, they achieved a √2 improvement in high-frequency sensitivity, resulting in a 5-8% increase in their astrophysical reach for Virgo [1] and 12-14% for Ligo [2]. However, this improvement came at the cost of increased radiation pressure noise in the 20-40 Hz range, limiting further noise reduction at higher frequencies. [3] [4].

In the O4 scientific run, LIGO and Virgo addressed this limitation by developing a Frequency Dependent Squeezing (FDS) source; both of the systems are based on a filter cavity to induce frequency rotation to FIS states. While LIGO successfully integrated FDS [5], Virgo encountered challenges related to technical noise and misalignment of the signal recycling cavity, restricting its implementation to FIS during O4b. Nevertheless, Virgo extensively tested and commissioned the FDS system in standalone mode with a homodyne detector [6]. Despite these challenges, Virgo's experience with FDS installation provided valuable insights for future detectors, particularly in the development of the Einstein Telescope's quantum noise reduction system.

This presentation aims to discuss the status of Virgo's Quantum Noise Reduction system at the beginning of the O4b scientific run, highlighting encountered challenges and adopted solutions that could be taken into account in the design of the ET FDS system. Notable issues found include the dependence of the filter cavity RTL on the optical axis, challenges in controlling the Filter Cavity detuning with the 1.2 GHz frequency shifted subcarrier beam, variations in relative detuning between green and infrared beams with mirror temperature when they are used to control in length the filter cavity, and issues induced by stray light.

[1] F. Acernese et al., Increasing the Astrophysical Reach of the Advanced Virgo Detector via the Application of Squeezed Vacuum States of Light, Phys. Rev. Lett. 123, 231108 (2019)
[2] M. Tse et al., Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy, Phys. Rev.Lett. 123, 231107 (2019).
[3] F. Acernese et al., Quantum Backaction on kg-Scale Mirrors: Observation of Radiation Pressure Noise in the Advanced Virgo Detector, Phys. Rev. Lett. 125, 131101 (2020)
[4] Y. Haocun, L. McCuller1, M. Tse1, N. Kijbunchoo, L. Barsotti, N. Mavalvala et al., Quantum correlations between light and the kilogram-mass mirrors of LIGO, Nature (London) 583, 43 (2020).
[5] D. Ganapathy et al. Broadband Quantum Enhancement of the LIGO Detectors with Frequency-Dependent Squeezing, Phys. Rev. X 13, 041021 (2023)
[6] F. Acernese et al. Frequency-Dependent Squeezed Vacuum Source for the Advanced Virgo Gravitational-Wave Detector, Phys. Rev. Lett. 131, 041403 (2023).

TDS Link

09:00 → 10:30 OSB: DIV4

ET Symposium Room 2.1

09:00 Div 4 chairs

Speakers: Andrew Levan (Radboud University), Giancarlo Ghirlanda (Istituto Nazionale di Astrofisica - Osservatorio di Brera & INFN sezione di Milano Bicocca), Susanna Vergani (GEPI, Observatoire de Paris - PSL, CNRS)

osb4_maastricht_v2.pptx

09:30 Multi-messenger observations in the Einstein Telescope era: binary neutron star and black hole - neutron star mergers

The multi-messenger and multi-wavelength observations of the remarkable GW170817 event have significantly enhanced our comprehension of kilonova and relativistic-jet-related emissions following a binary neutron star (BNS) merger. While the outcomes of black hole-neutron star (BHNS) mergers remain less observationally constrained, leveraging insights from BNS mergers enables us to partially bridge these knowledge gaps. Consequently, we are empowered to make well-founded prognostications regarding the anticipated electromagnetic (EM) counterparts of gravitational wave (GW) transients arising from both BNS and BHNS mergers, poised for detection in the near future. In two recent studies (Colombo et al., 2022 and 2023) we constructed a synthetic cosmological populations of BNS and BHNS mergers, incorporating cutting-edge computations of associated GW and EM emissions. Utilizing these models, we have forecasted the occurrences of these phenomena during the current (O4) and forthcoming (O5) observing runs of ground-based interferometric GW detectors, namely the Advanced LIGO and Virgo. In this talk, I will offer an exploration into the extension of these predictions to the era of the Einstein Telescope, unveiling the bright future of BNS and BHNS mergers.

Alberto_Colombo_ET.pdf

TDS link

09:45 Perspectives for kilonovae multi-messenger detections

The detection of the gravitational wave (GW) signal GW170817 and the electromagnetic (EM) signal AT2017gfo confirmed the association between binary neutron star (BNS) mergers and kilonovae (KNe) and showed the potential of joint detection to unveil the nature of neutron stars and the nucleosynthesis of heavy elements in the Universe. The next-generation GW interferometers, such as the Einstein Telescope (ET), are unprecedented resources to enhance the chances of detecting EM counterparts significantly enlarging the horizon of detectable BNS mergers, and dramatically improving the source parameter estimation. Starting from BNS merger populations based on population synthesis codes, we compute the number of detected mergers and estimate the source parameters within a Fisher-matrix approach for different configurations of ET operating alone or in a network of present or next-generation GW detectors. We compute the KN emission associated with the BNS merger population using numerical-relativity-informed fits for two different nuclear equations of state, and considering the influence of black hole prompt collapse on the kilonova signal. Furthermore, we include the emission from the afterglows of short gamma-ray bursts. In the talk, I will discuss the perspectives for ET observing in synergy with the Vera Rubin Observatory taking into account the present uncertainties on the rate of BNS mergers, neutron star mass distribution, and nuclear equation of state.

talk_loffredo.pdf

10:00 ET-WST synergy for next generation gravitational wave multi-messenger observations

The Einstein Telescope (ET) will detect up to 10$^{5}$ binary neutron star system mergers (BNS) per year beyond z~3, clearly revolutionizing gravitational waves (GW) multi-messenger (MM) astrophysics. The optical-near infrared electromagnetic (EM) counterparts of such BNS will likely be faint and to be found within the large GW signals error regions, among a huge number of contaminants. The bottleneck of GW MM science will be to gather the spectroscopic data required to discriminate against EM counterpart candidates, identifying and characterizing them. Therefore, new observational strategies to select GW events and detect the EM counterparts will be necessary, and they have to be prepared well in advance of ET operations.
I will present the results of the work I am carrying out within the Wide-field Spectroscopic Telescope (WST) science team and the MM division of the ET Observational Science Board to assess the impact of the next generation Integral Field Spectroscopy (IFS) and Multi-Object Spectroscopy (MOS) on the detection, identification and characterisation of EM counterparts of ET BNS, with the aim to provide the specifications required, and to prepare the synergy with ET.

Speaker: Sofia Bisero (GEPI, Observatoire de Paris, Université PSL, CNRS)

BISERO_ETSymposium.pdf

10:15 The great synergy of ET with next-generation GRB observatories

The huge luminosity, the redshift distribution extending at least up to z~10 and the association with the explosive death of very massive stars make long GRBs extremely powerful probes for investigating the early Universe (pop-III stars, cosmic re-ionization, SFR and metallicity evolution up to the “cosmic dawn”) and measuring cosmological parameters. At the same time, as demonstrated by the GW170817 event, GRBs are a key electromagnetic counterpart of gravitational waves produced by NS-NS and NS-BH merging events. GRB space mission projects for the next decade aim at fully exploiting these unique potentialities of the GRB phenomenon, thus providing an ideal synergy with the very large astronomical facilities of the future (e.g., ELT, CTA, SKA, Athena) and, in particular, with the Einstein Telescope (ET). For instance, the THESEUS mission, under study by ESA as candidate M7 for a launch in 2037, by providing an unprecedented combination of X-/gamma-ray monitors, on-board IR telescope and spacecraft autonomous fast slewing capabilities, would be a wonderful machine for the detection, multi-wavelength characterization and redshift measurement of any kind of GRBs and many classes of X-ray transients. Thanks to these unprecedented capabilities and a perfectly matched timeline with ET, this mission would thus provide at least several tens, and likely more than one hundred, EM counterparts to GW detections, thus greatly enhancing the scientific return of ET for multi-messenger astrophysics and cosmology, as well as extreme and fundamental physics with GRBs.

Speaker: Dr Lorenzo Amati (INAF - OAS Bologna)

amati-ET-Maastricht24.pdf

amati-ET-Maastricht24.pptx

10:45 → 11:15 Coffee Break

11:10 → 13:00 EIB

Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco

Zoom Room 2.18

11:15 ET-PP update

Speaker: Nadia Tonello (Barcelona Supercomputing Center)

202405.ETSymposium_WP8report_v1.pptx

12:00 Industrial engagement

Speaker: Stefano Bagnasco

11:15 → 13:15 ISB: Contributed Talks

Conveners: Jan Harms, Stefan Hild

ET-Symposium Room 2.2

11:15 Ferrara laboratory for birefringence measurements of substrates and reflective coatings

At the Physics Dept. and INFN section of Ferrara, Italy, we have two working sensitive polarimeters dedicated to measuring the birefringence 2D map of substrate samples, 2D map of the static birefringence of reflective coatings and birefringence noise of high reflectivity mirror coatings. One will be dedicated to static birefringence measurements (substrates and reflective coatings) and the second one to the mirror birefringence noise measurements. At the moment the first polarimeter is based on an entrance polarizer, two co-rotating half wave plates before and after the sample followed by an ellipticity modulator and finally by an analyser set to extinction. The sensitivity of this scheme allows ellipticity measurements of $ \lesssim 3\times10^{-6}$, dominated by systematics, corresponding to an optical path difference sensitivity of $\lesssim 1\times10^{-12}\;{\rm m}$. The second polarimeter has a high finesse Fabry-Perot cavity (${\cal F} \gtrsim 10^5)$ instead of the rotating half-wave plates. The ultimate noise of this second polarimeter is determined by the intrinsic birefringence mirror noise of the mirror coatings (more precisely intrinsic optical path difference noise) which can be measured and not by shot-noise. At $\approx 10$\;Hz the optical path difference sensitivity of the scheme (with ${\cal F} \approx 10^5$ and output power $P_0\approx$\;mW) is $\lesssim 10^{-19}\;{\rm m/\sqrt{Hz}}$. We will present the two systems and some preliminary results of birefringence maps on small samples.

Speaker: Guido Zavattini (University and INFN - Ferrara)

TDS link

11:35 Crystalline oxides for mirror coatings

In this presentation, the progress towards the realisation of crystalline oxide mirror coatings is reviewed.

Cr2O3 films on Al2O3 is our initial crystalline oxide model system where the relationship between the structural, optical and mechanical properties is investigated. Specifically the role of a lattice mismatch of about 5% on these properties will be reported.

In a second part, the roadmap for the growth of larger area coatings with the new 300 mm molecular beam epitaxy system - that has recently been installed - will be presented.

ET 8 May 2024.pdf

11:55 Minimizing Mechanical Losses through Partial Crystallization in Ion-Beam Sputtered Tantalum Oxide Thin Films

The standard post-deposition treatment on amorphous tantala (Ta2O5) mirror coatings consists in a 10 hours thermal annealing at 500°C temperature. This procedure reduces internal strains, thus lowering the coating loss angle. The coating remains amorphous during this procedure, which makes it optically homogeneous.
Treating the samples at higher temperatures and/or for longer annealing times may lead to the formation of crystalline regions inside the coating, which are generally considered detrimental from the optical point of view. It is however not clear to what point the annealing procedure can be pushed in order to achieve the best performances, eventually allowing for the presence of small amount of crystallized material.
In this work we performed controlled thermal annealing treatments on amorphous tantalum oxide (tantala, Ta2O5) thin films produced by Ion-Beam Sputtering in order to to achieve varying degrees of crystallized fraction. We characterized the microscopic structure of the annealed samples by combining different analytical techniques. Our investigation revealed that the amorphous films comprise randomly distributed crystalline grains, whose density and average size depends on the duration of thermal treatment.
Furthermore, we assessed the mechanical losses of the treated coatings via a Gentle Nodal Suspension (GeNS) system. Remarkably, we detected a substantial reduction in the coating's mechanical loss angle with respect to annealed amorphous coatings. The reduction in mechanical losses comes at the expense of an increase in optical scattering.
This observed improvement in mechanical loss angle may lead to the definition of alternative thermal treatments to improve the mechanical performances of coatings for gravitational wave detectors or other highly sensitive optical experiments.

Speaker: Valeria Milotti (Università degli Studi di Padova, INFN PD)

TDS link

12:15 Status of realising and testing compact local test mass displacement sensors using DFMI

A key technology to achieve the exquiste low-frequency sensitivity of the Einstein Telescope is to reduce the noise of local displacement sensors in the test mass suspension chains. We are developing a sensing infrastrcuture for this purpose based on the interferometer technique Deep Frequency Modulation Interferometry (DFMI) that enables us to realize compact sensors that can provide sub-picometer displacement sensitivity and absolute ranging. To realise this we are investigating the realisation of compact sensing heads, so called compact balanced readout interferometers (COBRIs) and we are developing advanced phase readout algorithms and are implementing them with FPGAs in the scalable MicroTCA infrastrcuture to realize the readout of dozens of sensors. Furthermore, we are also comissioning a test bed, an active seismic isolation vacuum facility, to probe the sensor usage and performance in vacuum on triple-suspensions borrowed from ET Pathfinder.
We will present the status of these developments and our test bed, as well as results from our efforts to use machine-learning to predict the motion of our seismically isolated platform.

Speaker: Oliver Gerberding (Universität Hamburg, Institut für Experimentalphysik)

TDS link

12:35 Superattenuators for the ET era

The development of the Superattenuator, over years of dedicated research and development by the National Institute for Nuclear Physics (INFN) in Pisa, has played a pivotal role in enabling the detection of gravitational waves signals down to an unprecedented 10 Hz frequency.

In fact, the Superattenuator, acting as a cascade of low-pass filters, has been a fundamental tool for the VIRGO interferometer, and then for Advanced VIRGO (AdV), in damping the ground motion - the main source of noise in the low frequency range - by more than 10 orders of magnitude.
As we set our sights on the next generation of gravitational wave detectors, with the goal of improving the sensitivity by more than one order of magnitude with respect to the 2nd generation detectors, and extending the detection band down to 2-3 Hz, it becomes evident that further improvements are necessary to push the boundaries of detection capability.

This necessitates a shift from conceptual innovation to targeted advancements in the design and mechanics of filters, sensors and actuators that build up the Superattenuator, for them to turn into real game changers and fulfill the ET design sensitivity.

We will focus here on some of the many aspects currently under consideration.

Concerning the filter concept, we will illustrate the redesign of the magnetic anti-spring (MAS) providing vertical attenuation, that aims at compacting and enhancing the symmetry of the system, thus pushing the crossbar vibration modes away from the low frequency range.

From the actuation point of view, we will report on the R&D efforts aimed at upgrading the seismic isolation platform into a six degrees-of-freedom active pre-isolator.

With the improvement of passive and active filters performances, the current state-of-the-art sensors will be way too noisy. This calls for the development of new accelerometers based on principles distinct from those currently employed. We will report on ongoing efforts in this direction.

TDS link

12:55 CAOS: an international laboratory for prototyping ET suspensions

The CAOS (Center for Applications on Gravitational Waves and Seismology) laboratory is going to be constructed in Perugia in the coming years. It will serve as an international facility where two full-scale ET suspensions will be built. Additionally, a Fabry-Perot cavity will be realized to facilitate various studies on the different noise sources characteristic of third-generation gravitational wave detectors. The aim of the presentation is to outline the current status of CAOS and the preliminary studies for the project's realization.

URL TDS

11:15 → 13:00 OSB: DIV10

ET Symposium Room 2.1

11:15 Div 10 chairs

Speakers: Anuradha Samajdar (University of Milan, Bicocca), Elena Cuoco, Prof. Gianluca Maria Guidi, Tania Regimbau

Div10_overview_ET_symposium_maastricht_May_2024.pdf

11:45 Binary Black Hole Parameter Estimation using a Conditioned Normalizing Flow

The improved sensitivity of the Einstein Telescope increases the observable volume of compact binary systems and extends the time window in which the inspiral phase is measurable. Neural Networks (NNs) can efficiently analyze the vast amount of data by reducing computational costs and runtime. This talk presents a fast Binary Black Hole parameter reconstruction by applying a conventional convolutional NN, which conditions a subsequent Normalizing Flow (NF). NFs can learn arbitrarily complex multimodal distributions in multiple dimensions and manifolds. Using the NF, an approximated posterior parameter distribution on an event-by-event basis is obtained faster than in real-time.

Speaker: Markus Bachlechner (RWTH Aachen University)

TDS Link

12:00 Impact of Correlated Noise on Third-Generation Gravitational-Wave Detectors: Biases in Parameter Estimation and Design Performance

In-depth understanding of correlated noise effects is critical for optimizing third-generation gravitational-wave detectors such as the Einstein Telescope. This presentation unfolds in two parts. In the first part, we explore the statistical formulation of the likelihood function, integrating correlated noise into parameter estimation for detector networks. Our analysis demonstrates that disregarding noise correlations can significantly compromise parameter estimation, resulting in significant biases in maximally correlated networks. These insights underscore the necessity of precise noise modelling to fully leverage the capabilities of next-generation detectors. The latter part of the talk evaluates colocated versus non-colocated detectors, using hypothetical scenarios with two L-shaped European detectors, and further analyses including a US detector. We present results showing that the colocated configuration, despite challenges in estimating extrinsic parameters, achieves improved accuracy in intrinsic parameter estimation when noise correlation is considered. With the addition of a US detector, the colocated configuration performs better than the non-colocated configuration in estimating extrinsic parameters in the highly correlated scenario, illustrating the non-trivial influence of noise correlations on detector performance and design. These findings emphasize the critical need for integrating noise correlation considerations into both the data analysis and design phases of third-generation gravitational wave detectors to ensure robust and accurate scientific discoveries

TSD link

12:15 Normalizing flows as an avenue to study overlapping gravitational wave signals

Due to its speed after training, machine learning is often envisaged as a solution to a manifold of the issues faced in gravitational-wave astronomy. Demonstrations have been given for various applications in gravitational-wave data analysis. In this work, we focus on a challenging problem faced by third-generation detectors: parameter inference for overlapping signals. Due to the high detection rate and increased duration of the signals, they will start to overlap, possibly making traditional parameter inference techniques difficult to use. Here, we show a proof-of-concept application of normalizing flows to perform parameter estimation on overlapped binary black hole systems.

Normalizing flows as an avenue to study overlapping gravitational wave signals

OverlappingSignalsNFsMaastricht.pdf

12:30 Robust parameter estimation on gravitational wave signals from binary neutron star inspirals within minutes

The gravitational waves emitted by binary neutron star mergers contain information on nuclear matter above saturation density. However, extracting this information and conducting parameter estimation remains computationally challenging and expensive. Wong et al. introduced Jim, a parameter estimation pipeline that combines relative binning and JAX features, such as hardware acceleration and automatic differentiation, into a normalizing flow-enhanced sampler for gravitational waves from BBH mergers. In this work, we extend the Jim framework to analyze gravitational wave signals from BNS mergers. We demonstrate that Jim can be used for full Bayesian parameter estimation of gravitational waves from BNS mergers within a few minutes, which includes the training of the normalizing flow. For instance, Jim can analyze GW170817 in 26 minutes (33 minutes) of total wall time using the TaylorF2 (IMRPhenomD_NRTidalv2) waveform, and GW190425 in around 21 minutes for both waveforms. We highlight the importance of such an efficient parameter estimation pipeline for several science cases and advocate for its ecologically friendly implementation of gravitational wave parameter estimation.

ET-0262A-24.pdf

13:00 → 14:00 Lunch

14:00 → 15:45 ISB: ISB discussions

Conveners: Jan Harms, Stefan Hild

ET-Symposium Room 2.2

14:00 → 14:30 OSB: DIV10

ET Symposium Room 2.1

14:00 Parameter estimation of the overlapping signals: descending in frequency and ascending in speed

The increased sensitivity of the Einstein Telescope will lead to a significant increase in the number of gravitational wave signals we can detect. In addition, it will allow us to observe the gravitational wave signals for a longer duration. While both of these factors, a large number of signals and longer signals can open windows to previously unexplored science cases, they also introduce the problem of overlapping signals. The increase in the number of detections and the duration of the signals will cause them to overlap, which leads to biases in the measurement of the signal’s source parameters. This can hinder the pursuit of precision science. The state-of-the-art parameter estimation pipelines have not been designed to analyze overlapping signals or long-duration signals. In this work, we present two different methods, hierarchical subtraction and joint parameter estimation, to perform parameter estimation of the overlapping signals. These methods are supplemented with a relative binning algorithm to speed up the parameter estimation and with the effect of earth rotation to attempt more realistic scenarios, especially for the long-duration signals emitted by binary neutron star systems or low-mass binary black hole systems. By performing parameter estimation on a large set of simulated gravitational wave signals we demonstrate the performance of the two methods.

overlapping_signal_et_symposium-2.pdf

14:15 Deep learning to detect compact binary coalescences. A test with Einstein Telescope MDC.

Data analysis of gravitational wave events will face many challenges in the ET era. The improvement of a factor 10 in the sensitivity translates to ~10^5 events/year while the broader sensitivity range at low frequencies will lead to longer-duration signals. A larger number of signals will lead to overlapping signals that will therefore amplify the computational burden, posing complex challenges for analysis pipelines.
Developing rapid detection and inference algorithms will be further crucial with the expected event rates detected by ET and for multimessenger follow-up observations.
We built a detection and early warning pipeline for CBC signals based on deep neural networks. Deep learning has been demonstrated to be a promising approach for the fast processing of gravitational wave data. The proposed architecture exploits the stacking of different neural networks to accomplish detection and parameter estimation with the possibility of early warning detection. In order to test this approach, we have applied our pipeline to the ET Mock Data Challenge.

Speaker: Lucia Papalini (Pisa)

Transformers: A new application of deep learning to gravitational wave data in ET

14:00 → 15:45 SCB/SPB

Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)

Zoom Room 2.3

14:00 Update on socio-economic studies

Speaker: Dr Leonardo Vargiu (University of Sassari)

14:20 Analysis of acoustic noise at Sos Enattos

Speaker: T. Bulik

Bulik-sosenattos-infrasound.pdf

14:40 Comparison of seismic noise in ETpathfinder and VIRGO

Speaker: M. Suchenek, T Bulik & M. Pietrzak

2024_05_et_pathfinder_v5.pdf

15:00 Update on wind park measurements in Sardinia

Speaker: Dr Giovanni Diaferia (INGV)

Results from WINES: Wind turbIne Noise assEsSment in the Italian site candidate for “Einstein Telescope”

15:20 Progress and plan on wind turbines in EMR

Speaker: A. Stahl

Stahl-Windturbines.pptx

14:30 → 15:30 OSB: DIV9

ET Symposium Room 2.1

14:30 Div 9 chairs

Speakers: Andrea Maselli, Michal Bejger (INFN Ferrara & CAMK PAN), Michele Mancarella (Milan-Bicocca)

OSB9 summary

15:00 Enhancing Fisher Matrix Results with Physically Motivated Priors

Next-generation gravitational wave interferometers, such as the Einstein Telescope, will observe an unprecedented volume of events. This requires analysis tools that can deal with large datasets. Our software GWFish utilizes Fisher matrix analysis, which is currently the state-of-the-art method in the field and can effectively evaluate detector performance.

We now want to present an improvement to parameter estimation's precision by adding priors into the standard GWFish analysis. Fisher matrix methods alone are, in fact, agnostic of the physical range of gravitational wave parameters. To address this, we have integrated physically motivated priors into the analysis in order to generate reliable posterior samples. Our method has been tested against the GWTC data and serves as an intermediate step between the Fisher approximation and the currently too-expensive Bayesian methods.

Dupletsa_ET_Symposium_Maastricht2024.pdf

Dupletsa_Maastricht_2024

15:15 Extending the Fisher matrix formalism towards the edges

The Fisher information matrix (FIM) formalism is nowadays widely used to forecast the parameter estimation (PE) capabilities of future GW detectors to avoid the high computational cost of Bayesian PE analyses.

Unfortunately, this formalism is known to fail in some regions of the GW parameter space, especially when strong parameter degeneracies are present. One of the best-known examples is the luminosity distance-inclination degeneracy, present for small or vanishing inclination angles. Crucially, this can prevent performing, e.g., cosmology studies involving GW+GRB measurements.

We will present a new approximant that extends to the standard FIM formalism treating the GW likelihood as exact in some parameter subspaces and keeping a low computational cost while allowing to obtain meaningful forecasts. Within this context, we also show how to include the effect of noise fluctuations in this likelihood, which is needed to avoid well-known biases in population analyses.

Speaker: Mr Francesco Iacovelli (University of Geneva)

ET-0218A-24.pdf

15:45 → 16:15 Coffee Break

16:15 → 17:45 ISB: Spare

Conveners: Jan Harms, Stefan Hild

ET-Symposium Room 2.2

16:15 From Optical Layout to Detector Layout

Speaker: Max Majoor (Nikhef)

ET-0295A-24

16:35 ISB2Infrastructure: next steps

Speaker: Jan Harms

16:55 ERC for superfluid helium feasibility tests

Speaker: Steffen Grohmann (KIT)

ERC Project GRAVITHELIUM

16:15 → 17:00 OSB: Blue book

Conveners: Dr Archisman Ghosh (Universiteit Gent), Marica Branchesi (Gran Sasso Science Institute), Michele Maggiore

ET Symposium Room 2.1

16:15 → 18:00 SCB/SPB

Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)

Zoom Room 2.3

16:15 Update on glitch studies

Speakers: Davide Rozza (INFN-LNS), Matteo Di Giovanni (La Sapienza Università di Roma - INFN Roma)

Update_on_glitch_studies

16:35 Triangle and L localization in Sardinia

ET Localization in Sardinia

16:55 Noise analysis in SPB and ISB/ANM

Speakers: Luca Naticchioni, Matteo Di Giovanni (La Sapienza Università di Roma - INFN Roma)

Noise Analysis in SPB and ISB/ANM

17:15 Discussion on Common Framework for noise impact estimation on detector performance

CommonFramework.pptx

17:35 General Discussion

202405_new_mandate.pptx

18:00 → 20:00 Reception at Limburg Government Hall

Thursday, 9 May

09:00 → 11:30 Plenary

Zoom Plenary Thursday and Friday

09:00 Welcome

09:20 ETC - Activities and plans of the collaboration

Speakers: Harald Lueck, Michele Punturo (INFN)

09:50 ETC - The CB and SSB activities

Speaker: Eugenio Coccia

10:10 OSB status

Speakers: Marica Branchesi (Gran Sasso Science Institute), Michele Maggiore

10:50 SPB Status

Speakers: Domenico D'Urso, Dr Wim Walk (Nikhef)

11:30 → 11:50 Coffee

11:50 → 13:10 Plenary

Zoom Plenary Thursday and Friday

11:50 ISB Status

Speakers: Jan Harms, Stefan Hild

12:30 EIB Status

Speakers: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco

TDS link - EIB Status

13:10 → 14:10 Lunch Break

14:10 → 16:20 Plenary

Zoom Plenary Thursday and Friday

14:10 LISA status and plans

Speaker: Monica Colpi (University of Milano Bicocca, Department of Physics)

14:30 LVK status

Speaker: Gianluca Gemme (INFN)

15:00 CE status and plans

Speaker: Lisa Barsotti

15:20 Introduction to Data Access models in large scientific environments

Speaker: Fernando Patat

15:40 Discussion on Data Access Policy (and maybe IGWIN)

16:20 → 16:40 Coffee

16:40 → 18:30 Plenary

Zoom Plenary Thursday and Friday

16:40 Poster Prize Award

16:50 SSB elected chairs presentations

Speakers: Anna Green (Nikhef), Ettore Majorana, Harald Lueck, Jessica Steinlechner, Luca Naticchioni, Mariafelicia De Laurentis, Monique Bossi (INFN), Paola Leaci (Sapienza University and Rome INFN - National Institute for Nuclear Physics), Susanne Milde (AEI/Milde Science Comms)

ET Editorial Committee

Speakers and Awards Committee

17:50 MDC current organization and future plans

Speaker: Tania Regimbau

18:10 Discussion

18:30 → 21:00 Early Carreer Social Event

The registration and walk towards the event location starts at the entrance of the St Jans Kerk.

Friday, 10 May

09:00 → 11:00 Plenary

Zoom Plenary Thursday and Friday

09:00 ETO status and updates

Speaker: Fernando Ferroni (GSSI)

09:15 Activities with CERN

Speaker: Patrick Werneke

09:35 Updateing the ET roadmap

Speaker: Andreas Freise

09:50 ET-PP status

Speaker: Mario Martinez

10:10 Update from ET Coordinators

Speaker: Stan Bentvelsen

10:30 TDR

11:00 → 11:20 Coffee

11:20 → 13:00 Plenary

Zoom Plenary Thursday and Friday

11:20 EMR update

Speaker: Stan Bentvelsen

11:40 Sardinia (TETI) update

Speaker: Giovanni Bisoffi (INFN)

12:00 ET communication activities

Speaker: Dr Vincenzo Napolano (EGO Communication Responsible)

12:20 Conclusions