II. Workshop on ET-LF TM Tower Integration

25 Mar 2025, 13:00 → 27 Mar 2025, 13:15 Europe/Rome

Building 200, room 139 (IJCLab in Orsay)

The ET-ISB Div. I Suspension and ET-ISB Division IV Vacuum and Cryogenics are organizing this joint workshop to advance ET-LF TM tower integration concepts following the discussion at last ET-ISB Fall workshop and ET annual meeting

The workshop objectives are the following:

• Overview on present super-attenuator (SA) design concepts / developments
• Integration of SA in LF TM towers (options, constraints, requirements)
• Planning towards a LF TM tower baseline design
• Note that a baseline is needed for the infrastructure planning, i.e. the cavern concept.
• The baseline shall not prevent us from developing / integrating smarter solutions in the future.

 

The meeting will last 2 full days: from 25 March starting at noon to 27 March until noon

There will be no registration fee but registration is mandatory to access the lab. 

Lunches will be taken at the CESFO canteen (16.47 € per lunch in cash). 

TDS link to the meeting minutes: ET-0094A-25

 

 

 

Detailed instructions to walk from the RER station to the auditorium

Tuesday 25 March

14:00 → 18:00 Status and project constraints

14:00 Introduction, scope and status of ET-LF TM tower integration

Speaker: Steffen Grohmann (KIT)

Introduction to 2nd ET-LF TM tower integration workshop

14:45 Status of infrastructure planning

Speaker: Patrick Werneke

Status of Infrastructure Planning

15:30 ET's Tower nodes: classification and subsystem integration

Methodology of efforts ongoing to classify ET's towers, following from the noise budget and high-level interferometer architecture. Discussion on the set of boundary conditions that are to be established for a solution-agnostic framework, from which we can do comparative design analysis.

Speaker: Romano Meijer (Nikhef)

Tower_integration_workshop_slides_v1.pptx

16:15 Coffee break

16:30 Stability analyses of IP base ring integration options

Speaker: Gregory Iaquaniello

2025-03-26 - ET-LF Tower Integration Workshop.pdf

17:15 ET Activities at LNF: Status and Future Directions

The primary objective of the activities conducted at LNF is to investigate and validate innovative strategies for the active mitigation of ice formation and electrostatic charging on mirrors, as well as to collaborate with EGO/Virgo on the passive mitigation of charge emission from ion pumps. These efforts are currently in progress, with preliminary results from prototype systems demonstrating the potential efficacy of the proposed approaches. In principle, these strategies could be successfully implemented in real-world applications.
However, to ensure the seamless integration of these mitigation strategies into the design of the ET towers and vacuum systems, further advancements in engineering and technological solutions are imperative. To align with the overall infrastructure timeline, it is crucial to initiate this R&D work at the earliest opportunity.
The goal of this presentation is to address these critical aspects and foster a constructive discussion on concrete R&D proposals, paving the way for the successful implementation of these strategies in future projects.

Speaker: Luisa Spallino

LNF_Activities.pdf

Wednesday 26 March

09:00 → 12:30 Payload and super-attenuator design

09:00 The payloads for the Test Masses of the ET-LF and ET-HF interferometers: status and perspectives

The payloads are the last stage suspensions for the test masses. They are designed to fullfil the requirements coming from the control system and and the sensitivity of the detector. The status of the designs for the payloads, both in the LF and HF interferometers, will be presented.

Speaker: Paola Puppo

The payloads for the Test Masses of the ET-LF and ET-HF interferometers: status andperspectives.

09:45 The reference solution: a Superattenuator for Einstein Telescope

The Superattenuator - a cornerstone in seismic isolation systems for ground-based interferometers - is recognized as the seismic isolation reference solution for the Einstein Telescope in both the 2011 and 2020 Technical Reference Documents.
As seismic isolation system design progresses, evaluating the impact of targeted interventions on the performance of existing solutions is essential for effective risk mitigation.
The need for an update of the Superattenuator arises not only from the increased sensitivity, but also from the requirement to suspend a heavier, cryogenic payload, which makes the mechanics more demanding and imposes constraints on the materials, that must be compatible with both vacuum and cryogenic conditions.
In the conservative approach of the reference solution, the design is preserved: the simple yet effective upgrade detailed here does not alter the concept, but focuses on adjusting construction parameters, allowing the Superattenuator to meet the more demanding requirements of a third-generation interferometer while preserving its well-established reliability and performance.

Speaker: Francesca Spada

A Superattenuator for the ET-LF Test Masses

10:30 Coffee break

11:00 Super-Attenuator Design Concept Integrating an Active Platform and an Inverted Pendulum

This work originates from the aim of reducing the height of the 17 m suspension chain considered in the ET 2011 Conceptual Design Report and its 2020 Update. The presentation focuses on the current state of design and modelling of a candidate solution integrating both an inverted pendulum and an active platform. This key feature allows reducing the height of the seismic attenuation chain, while satisfying the requirements in terms of residual longitudinal motion of the test-mass below the ET-LF design sensitivity reaching $7.45e{-24}$ Hz$^{-1/2}$ at 3 Hz.

Speaker: Thomas Giordano (ULiège)

ET_LF_Modeling_Status_260325.pdf

11:45 An Active platform for the Inverted Pendulum of the Superattenuator

The Seismic Isolation System of the Advanced VIRGO, based on the working principle of a multi-stage pendulum hung to a three legs mechanical structure of the Inverted Pendulum, is equipped with 3 Piezoelectric actuators encapsulated with a foot structure. So far,these tools were never used to compensate seismic motion at very low frequencies regime due to missing high sensitivity sensor and some difficulties to distinguish this component of noise from the others. Recently the INFN Pisa group started a deep revision of this transducer with the intent to improve its performance within a more complex control strategy together with the possibility to implement a similar device for the horizontal degrees of freedom in view of ET.

Speaker: Franco Frasconi (INFN Pisa)

ffra_26mar25.pdf

12:30 → 14:00 Lunch break

14:00 → 16:00 Discussion

16:00 → 16:30 Coffee break

16:30 → 18:00 Discussion

Thursday 27 March

09:00 → 10:30 Planning and documentation

10:30 → 11:00 Coffee break

11:00 → 13:00 Planning and documentation