XIV ET Symposium | Maastricht

Europe/Rome
MECC

MECC

Description

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. We will provide a Zoom link to all registered attendees.

 

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). 
Early Career Scientists enjoy Monday evening a scenic walk together from the MECC to a nearby café, where you connect over drinks and snacks (no registration).

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.
Registration
Register for the XIV ET Symposium
Participants
  • Adrian Schwenck
  • Alba Gonzalvez
  • Alba Romero-Rodríguez
  • Alberto Masoni
  • Alessandro Cardini
  • Alessandro Parisi
  • Alessandro Santarelli
  • Alessandro Trinca
  • Alessandro Variola
  • Alex Amato
  • Alexander Kappes
  • Alexandre Sevrin
  • Alexey Gervasyev
  • Alina Mariana Soflau
  • Ameer Sider
  • Andrea Contu
  • Andrea Cozzumbo
  • Andrea Lampis
  • Andrea Maselli
  • Andrea Moscatello
  • Andreas Freise
  • Andreas Haungs
  • Andrew Miller
  • Aniello Grado
  • Anirban Ain
  • Anna Green
  • Anthony Amorosi
  • Antonella Bianchi
  • Antonio Pasqualetti
  • Archisman Ghosh
  • Artem Basalaev
  • Ayatri Singha
  • Bas Swinkels
  • Benedikt Schober
  • Benno Willke
  • Bruno Giacomazzo
  • camilla de rossi
  • Carmelita Carbone
  • Cervane Grimaud
  • Cezary Turski
  • Charlotte Benning
  • Chris Van Den Broeck
  • Christian Stegmann
  • Chun-Fung Wong
  • Claudia Moreno
  • Claudia Taranto
  • Cleva cleva@oca.eu
  • Costantino Pacilio
  • Cristiano Ugolini
  • Davi Rodrigues
  • David Perez-Medialdea
  • David Wu
  • Davide Guerra
  • Davide Rozza
  • Deepali Agarwal
  • Diana Lumaca
  • Didier Verkindt
  • Diksha Diksha
  • Dinesh Doerga
  • Domenico D'Urso
  • Dorota Rosinska
  • Duncan Brown
  • Dániel Barta
  • Elena Codazzo
  • Elena Cuoco
  • Eleonora Loffredo
  • Eleonora Villa
  • Elias Vagenas
  • Emanuele Tofani
  • Enis Belgacem
  • Eugenio Coccia
  • Fabian Gittins
  • Fabio Bergamin
  • Fabrizio Barone
  • Federica Santucci
  • Federico De Lillo
  • Filippo D'Ammando
  • Flavio Travasso
  • Francesca Onori
  • Francesco Bianchi
  • Francesco Chiadini
  • Francesco Cireddu
  • Francesco Crescimbeni
  • Francesco Dessì
  • Francesco Fidecaro
  • Francesco Iacovelli
  • Freek Molkenboer
  • Freija Beirnaert
  • Gabriele Capoccia
  • Gabriele Franciolini
  • Gaetano Schillaci
  • Geert-Jan Vis
  • Geoffrey Compère
  • Geraldine Servant
  • Ghada Mahmoud
  • Giacomo Bruno
  • Gianluca Gemme
  • Gianluca Inguglia
  • Gianluca Maria Guidi
  • Gijs Nelemans
  • Giovanni Losurdo
  • Giovanni Luca Cardello
  • Giuseppe Greco
  • Giuseppe Sappa
  • Gonzalo Merino
  • Guido Zavattini
  • Hans Van Haevermaet
  • Harald Lueck
  • Harald Pfeiffer
  • Helios Vocca
  • Henning Vahlbruch
  • IN SOO YUK
  • Ines Francesca Giudice
  • Irene Fiori
  • Isabel Cordero-Carrión
  • Ivonne Zavala
  • Jan Harms
  • Jean Pierre Zendri
  • Jerome Degallaix
  • Jessica Steinlechner
  • Joachim Wolf
  • Joan Llobera Querol
  • Johannes Erdmann
  • John Osborne
  • Jonathan Bratanata
  • Jonathan Carter
  • Jonathan Perry
  • Joris van Heijningen
  • Julia Casanueva Diaz
  • Jürgen Van Gorp
  • Katharina-Sophie Isleif
  • Kumar Akhil Kukkadapu
  • Kyujin Kwak
  • Kyung-ha Lee
  • Kyungmin Kim
  • Lennard Busch
  • Leonardo Lucchesi
  • Lia Lavezzi
  • Lieke van Son
  • Lionel Jacques
  • Loic Rolland
  • Lorenzo Amati
  • Lorenzo Piga
  • Luca Latronico
  • Luca Massaro
  • Luca Naticchioni
  • Luca Negri
  • Luciano Di Fiore
  • Luciano Di Fiore
  • Luigi Scibile
  • Léon Vidal
  • M. Angeles Perez Garcia
  • Magda Jakubiak
  • Manuel Arca Sedda
  • Marc Andrés-Carcasona
  • Marc Van der Sluys
  • Marco Limongi
  • Marco Orsini
  • Marco Ricci
  • Marco Vardaro
  • Marek Biesiada
  • Maria Cifaldi
  • Maria Concetta Tringali
  • Maria marsella
  • Mariana Fazio
  • Mariateresa Crosta
  • Marica Branchesi
  • Marije Barel
  • Mario Martinez
  • Mariusz Suchenek
  • Mark Hannam
  • massimiliano razzano
  • Mathijs Baars
  • Matteo Di Giovanni
  • Matteo Scialpi
  • Matteo Serra
  • Maxime Fays
  • Michael Vervaeke
  • Michele Maggiore
  • Michele Mancarella
  • Michele Moresco
  • Michele Punturo
  • Mike Lindner
  • Milan Wils
  • Monique Bossi
  • Morgane Zeoli
  • Neeraj Yadav
  • Niccolò Muttoni
  • Nick Van Remortel
  • Nicolas Arnaud
  • Nicole Busdon
  • Nicole Knust
  • Niklas Nippe
  • Oliver Gerberding
  • Oliver Pooth
  • Ornella Juliana Piccinni
  • Oussama EL MECHERFI
  • Pablo Barneo
  • Pablo García Abia
  • Paola Leaci
  • Paola Puppo
  • Paolo Pani
  • Patrice Verdier
  • Patricia Lamas
  • Patrick Werneke
  • Paweł Szewczyk
  • Peera Simakachorn
  • Peppe Junior Valentino D'Aranno
  • Peter Cuijpers
  • Peter Ván
  • Peter Weßels
  • Philippe Orban
  • Piero Chessa
  • Piero Rapagnani
  • Pieter Reumers
  • Qian Hu
  • Ralph Engel
  • Reinhardt Rading
  • Riccardo Murgia
  • Riccardo Travaglini
  • Robert Joppe
  • Robert Kovacs
  • Romano Meijer
  • Rosa Valiante
  • Rosario De Rosa
  • Sarah Baimukhametova
  • Sasa Topic
  • Sascha Rieger
  • Severin Nadji
  • Silvia Piranomonte
  • Simon Maenaut
  • Sina Koehlenbeck
  • Sofia Bisero
  • Soumen Roy
  • Stefan Danilishin
  • Stefan Hanke
  • Stefan Krischer
  • Stefano Bagnasco
  • STEFANO FOFFA
  • Steffen Grohmann
  • Steven Schramm
  • Sungho Lee
  • Susanne Milde
  • Suzanne Assis de Souza Melo
  • Tamara Bud
  • Tania Regimbau
  • Tanja Hinderer
  • Teng Zhang
  • Thomas Thümmler
  • Tim Kuhlbusch
  • Tobia Matcovich
  • Tobias Schoon
  • Tomasz Bulik
  • Tomislav Andric
  • Tommaso Chiarusi
  • Tsun Ho Pang
  • Ulyana Dupletsa
  • Valentina Mangano
  • Van Long Hoang
  • Ville Vaskonen
  • Violetta Sagun
  • Waleed Esmail
  • Wim Walk
  • Xingrui Peng
  • Yohei Nishino
  • Young-Min Kim
  • Yuhang Zhao
  • Yuliya Hoika
  • Yves Vanbrabant
  • Zeb Van Ranst
  • +107
    • 9:00 AM
      Excursion E-TEST Liège (times TBC)
    • OSB: Pre-Session Room 2,2

      Room 2,2

      MECC

    • SCB/SPB: Pre-Session Room 2,1

      Room 2,1

      MECC

      Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)
    • 1
      Registration
    • ISB: Optical Layout / Detector Layout Room 2,1

      Room 2,1

      MECC

      Conveners: Anna Green (Nikhef), Jerome Degallaix (Laboratoire des Matéraux Avancés)
    • OSB: DIV1 Room 2,2

      Room 2,2

      MECC

    • SCB/SPB Room 2,3

      Room 2,3

      MECC

      Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)
    • 3:00 PM
      Coffee Break
    • ISB: Optical Layout / Detector Layout Room 2,1

      Room 2,1

      MECC

      Conveners: Anna Green (Nikhef), Jerome Degallaix (Laboratoire des Matéraux Avancés)
    • OSB: DIV2 Room 2,2

      Room 2,2

      MECC

    • SCB/SPB Room 2,3

      Room 2,3

      MECC

      Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)
    • ISB: HF Suspension Requirements Room 2,1

      Room 2,1

      MECC

      Convener: Stefan Hild
    • OSB: DIV3 Room 2,2

      Room 2,2

      MECC

    • ISB: Electronics / Controls Strategy Room 2,1

      Room 2,1

      MECC

      Conveners: Bas Swinkels (Nikhef), Dr Loic Rolland (LAPP)
    • EIB 2,18

      2,18

      MECC

      Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco
    • ETO: Engineering Room 2,3

      Room 2,3

      MECC

      Convener: Patrick Werneke
    • ISB: Integrated LF Tower Design Room 2,1

      Room 2,1

      MECC

      Conveners: Conor Mow-Lowry, Prof. Fulvio Ricci (University of Rome Sapienza), Steffen Grohmann (KIT)
    • OSB: OSB-DIV3 Room 2,2

      Room 2,2

      MECC

    • OSB: OBS-DIV5 Room 2,2

      Room 2,2

      MECC

    • 10:45 AM
      Coffee Break
    • EIB Room 2,18

      Room 2,18

      MECC

      Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco
    • ETO: Engineering Room 2,3

      Room 2,3

      MECC

      Convener: Patrick Werneke
    • ISB: Integrated LF Tower Design Room 2,1

      Room 2,1

      MECC

      Conveners: Conor Mow-Lowry, Prof. Fulvio Ricci (University of Rome Sapienza), Steffen Grohmann (KIT)
    • OSB: OSB-DIV3 Room 2,2

      Room 2,2

      MECC

    • ISB: Infra Interface Discussion Room 2,1

      Room 2,1

      MECC

      Conveners: Jan Harms, Stefan Hild
    • OSB: OBS-DIV6 Room 2,2

      Room 2,2

      MECC

    • 2
      Executive Board
    • 1:00 PM
      Lunch Break Maastricht University (behind the building) (Duboisdomein 30)

      Maastricht University (behind the building)

      Duboisdomein 30

      https://maps.app.goo.gl/hyJhuccGnr2TR8mH8. 5min walk.
    • ETO: Project Office Room 2,3

      Room 2,3

      MECC

      Convener: Alessandro Variola (Istituto Nazionale di Fisica Nucleare)
    • ISB: Contributed Talks Room 2,1

      Room 2,1

      MECC

      Conveners: Jan Harms, Stefan Hild
    • OSB: OSB-DIV6 Room 2,2

      Room 2,2

      MECC

    • OSB: DIV7 Room 2,2

      Room 2,2

      MECC

    • 3:45 PM
      Coffee Break
    • ETO: Roadmap Room 2,3

      Room 2,3

      MECC

      Conveners: Andreas Freise, Fernando Ferroni (INFN Roma 1)
    • ISB: Contributed Talks Room 2,1

      Room 2,1

      MECC

      Conveners: Jan Harms, Stefan Hild
    • OSB: DIV7 Room 2,2

      Room 2,2

      MECC

    • OSB: DIV8 Room 2,2

      Room 2,2

      MECC

    • Posters
      • 3
        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.

      • 4
        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.

      • 5
        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.

      • 6
        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.

      • 7
        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.

      • 8
        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.

      • 9
        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)
      • 10
        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
      • 11
        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.

      • 12
        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.

      • 13
        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.

      • 14
        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.

      • 15
        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.

      • 16
        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)
      • 17
        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.

      • 18
        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.

      • 19
        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.

      • 20
        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.

      • 21
        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.

      • 22
        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

      • 23
        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)
      • 24
        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.

      • 25
        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.

      • 26
        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
      • 27
        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.

      • 28
        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)
      • 29
        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)
      • 30
        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.

      • 31
        The case for instrumented baffles in ET

        A first instrumented baffle was successfully installed in Virgo in spring 2021.
        Virgo plans a second upgrade with second generation instrumented baffles designed and constructed by IFAE to place them along the main FP cavities. It is considered a development that might be a natural part of the design of the new generation experiments. The main mirrors in the optical cavities are the core of the experiments, and the possibility of implementing active monitoring in ultra-high vacuum conditions constitutes a genuine technological breakthrough. A set of fixed instrumented baffles, similar to those developed for Virgo, placed in strategic locations along the arms can also provide a viable solution for an unresolved problem in the pre-alignment of the optical cavities in ET and the Cosmic Explorer experiment in the USA, with arm’s lengths of more than 10 KM. In this contribution we summarise the performance of the instrumented baffle in the last three years in Virgo and discuss the case for considering instrumented baffles in ET main arms.

      • 32
        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.

      • 33
        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.

      • 34
        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.

      • 35
        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.

      • 36
        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.

      • 37
        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.

      • 38
        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)
      • 39
        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.

      • 40
        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.

      • 41
        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.

      • 42
        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.

      • 43
        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."

      • 44
        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.

      • 45
        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)
      • 46
        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.

      • 47
        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.

    • 48
      Executive Board
    • EIB Room 2,3

      Room 2,3

      MECC

      Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco
    • ISB: Contributed Talks Room 2,1

      Room 2,1

      MECC

      Conveners: Jan Harms, Stefan Hild
    • OSB: DIV8 Room 2,2

      Room 2,2

      MECC

    • OSB: DIV4 Room 2,2

      Room 2,2

      MECC

    • 10:45 AM
      Coffee Break
    • EIB Room 2,3

      Room 2,3

      MECC

      Conveners: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco
    • ISB: All - Discussions Room 2,1

      Room 2,1

      MECC

      Conveners: Jan Harms, Stefan Hild
    • OSB: DIV4 Room 2,2

      Room 2,2

      MECC

    • OSB: DIV9 Room 2,2

      Room 2,2

      MECC

    • 1:00 PM
      Lunch Maastricht University (behind the building) (Duboisdomein 30)

      Maastricht University (behind the building)

      Duboisdomein 30

      https://maps.app.goo.gl/hyJhuccGnr2TR8mH8. 5min walk.
    • ISB: Spare Room 2,1

      Room 2,1

      MECC

      Conveners: Jan Harms, Stefan Hild
    • OSB: DIV9 Room 2,2

      Room 2,2

      MECC

    • SCB/SPB Room 2,3

      Room 2,3

      MECC

      Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)
    • OSB: DIV10 Room 2,2

      Room 2,2

      MECC

    • 3:45 PM
      Coffee Break
    • ISB: Spare Room 2,1

      Room 2,1

      MECC

      Conveners: Jan Harms, Stefan Hild
    • OSB: DIV10 Room 2,2

      Room 2,2

      MECC

    • SCB/SPB Room 2,3

      Room 2,3

      MECC

      Conveners: Domenico D'Urso, Dr Wim Walk (Nikhef)
    • OSB Room 2,2

      Room 2,2

      MECC

    • 6:00 PM
      Reception at Limburg Government Hall Limburglaan 10, 6229 GA Maastricht

      Limburglaan 10, 6229 GA Maastricht

    • Plenary St Janskerk

      St Janskerk

      Vrijthof 24, Maastricht
      • 49
        Welcome
      • 50
        ETC - Activities and plans of the collaboration
      • 51
        ETC - The CB and SSB activities
        Speaker: Eugenio Coccia
      • 52
        OSB status
        Speakers: Marica Branchesi (Gran Sasso Science Institute), Michele Maggiore
      • 53
        SPB Status
        Speakers: Domenico D'Urso, Dr Wim Walk (Nikhef)
    • 11:30 AM
      Coffee
    • Plenary St Janskerk

      St Janskerk

      Vrijthof 24, Maastricht
      • 54
        ISB Status
        Speakers: Jan Harms, Stefan Hild
      • 55
        EIB Status
        Speakers: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco
    • 1:10 PM
      Lunch Break
    • Plenary St Janskerk

      St Janskerk

      Vrijthof 24, Maastricht
      • 56
        LISA status and plans
      • 57
        CE status and plans
        Speaker: Lisa Barsotti
      • 58
        LVK status
        Speaker: Gianluca Gemme (INFN)
      • 59
        Introduction to Data Access models in large scientific environments
        Speaker: Fernando Patat
      • 60
        Discussion on IGWN and Data Access
    • 4:20 PM
      Coffee
    • Plenary St Janskerk

      St Janskerk

      Vrijthof 24, Maastricht
      • 61
        Poster Prize Award
      • 62
        SSB elected chairs presentations
      • 63
        MDC current organization and future plans
        Speaker: Tania Regimbau
      • 64
        Discussion
    • Plenary St Janskerk

      St Janskerk

      Vrijthof 24, Maastricht
      • 65
        ETO - 1
      • 66
        ETO - 2
      • 67
        ETO - 3
      • 68
        ETO - 4
      • 69
        TDR
    • 11:00 AM
      Coffee
    • Plenary St Janskerk

      St Janskerk

      Vrijthof 24, Maastricht
      • 70
        EMR update
        Speaker: Stan Bentvelsen
      • 71
        Sardinia (TETI) update
      • 72
        ET communication activities
        Speaker: Dr Vincenzo Napolano (EGO Communication Responsible)
      • 73
        Conclusions