Summary and Plans for the WG3 activity

H.Lück, M.Punturo

In the ILIAS proposal…• WP3: An European Strategy for Future Antennas

– Plan the enhancement of the performances of the European gravitational wave detectors and to organise their collective operation.

– Objectives:• To determine scientific objectives that could be attained through

short term improvements, optimisation and association of detectors now available in Europe.

• To establish the bases for integrating existing and future gravitational wave detectors in a coherent network.

• To draft a plan for a European network of gravitational wave detectors at the 2010 horizon

From the Annex 1

First years activity

Working group members• The members of this group, appointed at the first

GWA Executive Board, are:Co-Chairmen

H.LückMPI für Gravitationsphysik, AEI, Hannover, Germany

M.PunturoINFN Perugia, Italy

Appointed ParticipantsK.Strain IGR, Glasgow, Great Bretain

R.Flaminio EGO, Italy-France

V.Fafone INFN Frascati, Italy

M.Bonaldi IFN-CNR and ITC, Trento, Italy

D.Enard EGO, Italy-France

L.Gottardi Leiden University, Leiden, The Netherlands

The first task• “Definition of a list of possible short term

improvements”– Few words for an ambitious target– Need of wide competences– Many R&D activities in the World

• Necessity to enlarge the working group• Open the meeting to many European and external experts• Need to interlace this activity with WP1, WP2 and STREGA

activities (joint meetings)• Connect the activity of this working group with the

development programs of each experiment

WP3 the method• To organize the discussion and to reach the objectives, a list of

items that are affecting (or will affect) the current (future) GW detectors has been defined

f

h(f)

Low frequency noise:•Advanced suspensions

High frequency noises:•High power lasers•Signal recycling

Middle frequency noises:•Mirror substrate materials•Coatings

• Technologies:– Reduction of the technical noises

– Thermal compensation

– Advanced detector injection optics

… WP3 the method• Resonant detectors:

Geometries and materials

Read-out schemes

Geometrically based mode selection

WP3: the meetings• First meeting: Cascina (It), 8-9 July 2004

– Devoted to the presentation of the activities of each research group– Status of each detector– Organization of short and middle term objectives– Discussion on the integration of the WP3 activities in the “merging”

process between the European GW collaborations

• Second meeting: Hannover (Germany), 21-22 October 2004– Visit of the GEO detector– High power laser research in GEO– Mirror Substrate research in LSC– Highlights on GEO High Frequency– Co-located interferometers– Highlights on advanced Virgo design– Dual Detector

…WP3: the meetings• Third meeting: Legnaro (It), 27-28 January 2005

– Visit to the Auriga detector– High frequency GW sources (in collaboration with WG2)– Signal recycling technologies– Presentation of a common scenario of development of resonant detectors– Starting up of the common work between GEO and Virgo on detectors

evolution

• Fourth meeting: Glasgow (UK), 11-12 April 2005– Meeting largely devoted to the GEO-Virgo future joint progresses

• Discussion on a coordinated evolution between Virgo and GEO• Contribution of GEO members to the design of the advanced Virgo detector

– Technical talks:• GEO HF & scientific case (WP2)• Flat beams• Fiber mode cleaner• Limited amplifiers for resonant detectors

– Thermal noise activities in Glasgow

WP3 Glasgow meeting Souvenir

…WP3: the meetings

• Fifth meeting: Cascina (It), 9 June 2005– Actuation electronics for future detectors

– Optical configurations for advanced VIRGO, SR (via telecon)

– Large mass spherical detector sensitivity

– New results on photothermal effect: size and coating effects

– Thermal corrections (via telecon)

• The Last meeting: Perugia (It), 21-23 September 2005: – ESF Exploratory Workshop

ESF workshop in Perugia

• Gravitational Wave Week in Perugia– WP1 meeting– European Science Foundation Meeting + WP3– GWA Executive Board

Summary of the last year• Many meetings and common discussions pushed to

have a shared view of the evolution of the GW detectors in Europe

• Technical presentations focused the attention on the technologies that can be shared between the different detectors and developed in collaboration– Fused silica suspension– High power lasers– …

• “Political” discussion reduced the distance between the European GW scientific communities – We are realizing the “miracle” to start the writing of an

Advanced Virgo document with an important contribution by GEO members

This 1,5 years Plan9.N5 - Table 2 – GWA - Second 18 months Implementation Plan

Tasks and Deliverables 1st To 6th

Month 7th To 12th

Month 13th To 18th

Month

WP 3 : European strategy for future antennas Tasks:

3.1 - Evaluation of the proposed short

term improvements

3.2 - Definition of the technologies to

be shared between the different European detectors

3.3 - First draft of a common document

on short term upgrades and parallel development of the European detectors

3.4 - International workshop on European GW detectors evolution

3.5 - Common document on short term

upgrades

3.6 - First investigation on middle and

long term upgrades

Deliverables:

- Annual Report

ok

Evaluation of the proposed short term improvements• For the Virgo detector the following have been identified as short

term upgrades:– The increase of the power circulating in the Fabry-Perot cavities by inserting

a laser amplifier in the injection system. • (…) The impact on the specification of the injection system is under evaluation

particularly taking the thermal lensing of the Faraday Isolator into account.

– The installation of a thermal compensation system. • (…) thermal lensing due to the larger power circulating• (…) fine tuning of the reflectivity of the recycling mirror.

– Improvement of the actuation system, through a lower noise driving electronics.

• With the installation of a split path electronic, (…).

– Realization of a monolithic fused silica suspension for the Virgo main mirrors.

• This permits to reduce the thermal noise of the suspension. The compliance with the stringent cleanliness and safety requirements of Virgo must be still verified in a strongly suggested engineering activity that should determine if this is really a short term upgrade

EGO R&D programme• In its effort of supporting the European GW activities

development, EGO is financing two R&D activities in FS suspension: – Realization of a FS fiber production machine based on “standard” H2-O2

flames (Perugia) • Completely automated• Long fibers (>70 cm)• Ready to be mounted in the new experimental area in EGO

– Realization of a FS fiber production machine based on a CO2 laser (Glasgow)

• New design• Ready in April

• The performances of these two tools will be evaluated in a long engineering program started in Virgo/EGO to finalize the realization of a monolithic FS suspension for Virgo

… Evaluation of the proposed short term improvements

• (…) the GEO600 detector will get several sequential upgrades in the timeframe of 2007 to 2014 in order to provide scientifically useful data in the frequency range above 500 Hz to the GW detector network. The following upgrades are under discussion:– Step-by-step laser power increase by first inserting amplifier stages into

the beam path and later on switch to a different high power laser system. (…)

– Reduction of the finesse of the mode cleaners in order to avoid technical problems.

– Thermal compensation of the BS lensing by irradiating the beam splitter with an auxiliary beam of a CO2 laser.

– Further reduction of the shot noise can be achieved by injecting squeezed light into the interferometer via the output port. This technique is under development in the laboratories in Hannover and can be implemented towards the end of the timeframe mentioned above

– An exchange of the main optics of GEO600, i.e. the folding mirrors, the inboard (end) mirrors and the beam splitter is an option for decreasing the thermal noise in the frequency range around 1 kHz.(to be investigated)

… Evaluation of the proposed short term improvements• The currently operating resonant bar detectors (Auriga and the ROG detectors

Explorer and Nautilus) will be upgraded in the time frame 2006-2007. The target is to maintain their sensitivity comparable (in their 100 Hz detector bandwidth) with the sensitivity of the best operating interferometers and to give useful information on occurring astrophysical events during the planned future joint observation with interferometric detectors. These upgrades will be scheduled in order to keep always at least two detectors in data taking.

• The planned upgrades are :– The cooling of Auriga and Nautilus to ultracryogenic temperatures (about

100 mK), because all the fundamental noises in resonant detectors decrease with temperature.

– The implementation of nearly quantum limited readouts and more efficient electromechanical transducers.

• MiniGRAIL is close to start the first scientific run. The spheroidal modes will be monitored by three capacitive transducers. In order to fully exploit the sphere capability to reconstruct all the GW paramenters and the arrival direction, the near term planned upgrade will be the installation of the complete readout set up made of six transducers in the proper geometrical configuration and, as for bar detectors, the use of quantum limited SQUID amplifiers.

This 1,5 years Plan9.N5 - Table 2 – GWA - Second 18 months Implementation Plan

Tasks and Deliverables 1st To 6th

Month 7th To 12th

Month 13th To 18th

Month

WP 3 : European strategy for future antennas Tasks:

3.1 - Evaluation of the proposed short

term improvements

3.2 - Definition of the technologies to

be shared between the different European detectors

3.3 - First draft of a common document

on short term upgrades and parallel development of the European detectors

3.4 - International workshop on European GW detectors evolution

3.5 - Common document on short term

upgrades

3.6 - First investigation on middle and

long term upgrades

Deliverables:

- Annual Report

ok

ok

FS suspensionDigital controls

High power lasersSignal recycling

Coatings

Definition of the technologies to be shared between the different European detectors

SQUID amplifiers

Capacitive transducers

This 1,5 years Plan9.N5 - Table 2 – GWA - Second 18 months Implementation Plan

Tasks and Deliverables 1st To 6th

Month 7th To 12th

Month 13th To 18th

Month

WP 3 : European strategy for future antennas Tasks:

3.1 - Evaluation of the proposed short

term improvements

3.2 - Definition of the technologies to

be shared between the different European detectors

3.3 - First draft of a common document

on short term upgrades and parallel development of the European detectors

3.4 - International workshop on European GW detectors evolution

3.5 - Common document on short term

upgrades

3.6 - First investigation on middle and

long term upgrades

Deliverables:

- Annual Report

ok

In progress

ok

Done!

Next future plan• The activity evolution of the WP3 is defined in the plan:

– Continue to support the writing of the Virgo+ and Advanced Virgo document

• Enlargement of the WP3 group to the Advanced Virgo working groups members

• Organize meetings dedicated to this subject

– Insert this document in a more general scenario of evolution of the European GW detectors

– Support the know-how exchange between the different detectors

– Start to look beyond the short term upgrades

• Next meeting?– December in …