n5/wg3: future gw detectors in...

Chambery, February 27th, 2007 1

Raffaele FlaminioEGO and IN2P3/LAPP

N5/WG3:Future GW detectors in Europe

Summary- Introduction- Purposes of WG3- The GW roadmap

- Virgo+ and GEO-HF- Advanced Virgo- 3rd generation ITF

- Conclusions http://www.ego-gw.it/ILIAS-GW/


Present GW detectors possibilities

• Gravitational collapses in the galaxy (or nearby galaxies)• Test upper limits of known galactic pulsars (and look for unknown ones)• Search for coalescing neutron stars up to a max distance of ~30 Mpc• Search for merger of binary black holes up to a max distance of ~150 Mpc• The unknown


Toward GW astronomy

• Present detectors will test upper limits

• Even in the optimistic case rate too low to start GW astronomy

• Need to improve the sensitivity

• Increase the sensitivity by 10 ⇒ increase the probed volume by 1000

• Plans to improve the present detectors


Present limitations…. and ways to improve

1 10 100 1000 1000010-23

10-22

10-21

10-20

10-19

10-18

(a) Virgo Nominal sensitivity (b) Seismic noise (c) Pendulum thermal noise (d) Mirror thermal noise (e) Shot Noise

h(f)

[1/

sqrt

(Hz)

]

Frequency [Hz]

(a)

(b)

(c)

(d)

(e)

• Seismic noise- better active seismic isolation - longer and softer seismic isolation system- seismic noise reduction ! Go undergound



1 10 100 1000 1000010-23

10-22

10-21

10-20

10-19

10-18


h(f)

[1/

sqrt

(Hz)

]

Frequency [Hz]

(a)

(b)

(c)

(d)

(e)

• Pendulum thermal noise- decrease pendulum friction- better suspensions wires- better wire clamping- monolithic suspensions- cryogenic suspensions



1 10 100 1000 1000010-23

10-22

10-21

10-20

10-19

10-18


h(f)

[1/

sqrt

(Hz)

]

Frequency [Hz]

(a)

(b)

(c)

(d)

(e)

• Mirror thermal noise- decrease mirror internal friction- presently limited by friction in the coating- first decrease coating mechanical losses- then better mirror substrates- then low temperatures


• Shot noise- Increase power stored in the interferometer (increase laser power, decrease optical losses)- But attention to:1) thermal deformation

- improve thermal compensation- decrease light absorption

2) radiation pressure noise - increase mirror mass- optimize optical configuration (signal recycling)- use non classical light (light squeezing)


1 10 100 1000 1000010-23

10-22

10-21

10-20

10-19

10-18


h(f)

[1/

sqrt

(Hz)

]

Frequency [Hz]

(a)

(b)

(c)

(d)

(e)


Scope of the ILIAS-N5 WG3• Objective of WG3: Discuss plans for the enhancement of performances of the European GW detectors

• Questions for WG3- what are the technologies available now and in the future ?- what is the best strategy to upgrade existing detectors ?- what is the road toward new detectors/infrastructures ?

• Eight people appointed as permanent members of WG3:- three from Virgo, two from GEO and three from the resonant detectors- meetings open and other experts invited at the meetings

• Group coordinated by M. Punturo (INFN Perugia) and H. Lueck (MPI Hannover)

• Ten meetings held since the beginning of ILIASNext meeting: Amsterdam, Netherland, March 9 2007http://www.ego-gw.it/ILIAS-GW


WG3 implementation plan

- Finalization ofthe ‘White book’- Discussion of‘White book’ withfunding agencies- Writing of finalreport

- Evaluation ofcompatibility amongproposed long-termscenarios- Draft of a credibleplan for a Europeannetwork ofgravitational wavesdetectors at the 2012horizon

- Presentation of shortterm plan to thefunding agencies- Definition of realisticobjectives for newgeneration antennas- Definition ofrequirements andneeds for possible nextgeneration antennas

- Evaluation of proposedshort term improvements- Preparation of adocument describing aproposition for shortterm improvements.

- Working groupsetup- Definition of a listof possible short-termimprovements

YEAR 5(2008-09)

YEAR 4(2007-08)

YEAR 3(2006-07)

YEAR 2(2005-06)

YEAR 1(2004-05)

• Phase I: identify and propose short term improvements of existing detectors

• Phase II: study new generation antenna


The situation in 2004 (ILIAS t0)• Cryogenic resonant detectors- bars in operation since several years (AURIGA, Explorer, Nautilus)- development/study of spherical detectors in the Netherlands and in Italy- start of DUAL R&D in Italy

• GEO and LIGO under commissioning- LIGO had just reached resonant bars sensitivity but with much larger bandwidth

• Virgo commissioning just started- interferometer ‘first lock’ in 2004


The situation today• Cryogenic resonant detectors- bars operating continuously; but upgrade to ultra-cryogenic temperature cancelled- development of spherical detector (miniGRAIL) in the Netherlands (cancelled in Italy)- DUAL R&D going on in Italy

• LIGO reached design sensitivity- long data taking in progress- Advanced LIGO approved by NSF construction to start in 2008

• Virgo and GEO under commissioning- approaching design sensitivity- Virgo - LSC data sharing agreement signed


WG3: Short term improvements• Discussions initially considered a wide range of technologies

• Then progressively more and more focus on laser interferometer detectors

• Short term improvements of Virgo and GEO- discussion took advantage from a nice complementarities- Virgo:advanced seismic isolation, traditional steel wire mirror suspension, no signal recycling- GEO:simpler seismic isolation but integrating advanced technologies such as monolithicsuspensions and signal recycling

• Two short term improvements proposed to the institutions and approved in 2005- GEO-HF- Virgo +

• And then study Advanced Virgo design


From GEO to GEO-HF• GEO-HF- not the name of a new detector but rather the name of a program- sequential upgrades of GEO- prototype research to prepare these upgrades

• Motivations- provides scientifically interesting data until Advanced Interferometers will come on-line- support transit of 3rd generation interferometer research to detector subsystems or detector configuration (as it was the case with GEO and 2nd generation ITF)

• Envisaged upgrades:- increase circulating power- optimise signal recycling- use of squeezed light- reduce coating thermal noise (if possible).

• Timeline: start upgrading after extended data taking 2007/2008

Potential sensitivity curves


1 10 100 1000 1000010-23

10-22

10-21

10-20

10-19

10-18

h(f)

[1/s

qrt(

Hz)

]

Frequency [Hz]

50W/2 + new losses model 50W/2 + current mirrors Nominal Virgo 50W/2 + new losses model+FS suspensions Virgo+ with Newtonian Noise

The Virgo+ upgrade• Virgo has already an “advanced” seismic isolation system

• Possibility to improve the sensitivity with a set medium scale incremental improvementsCompatibility with the main Virgo subsystemsSame optical lay-outLimited shutdownLimited commissioning

• Planned upgrades- Fused silica suspensions - Larger laser power: 20W → 50W

⇒ mirror shape thermal compensation- Electronics and control system

• Coalescing binaries ‘horizon’ maximum distance for optimally oriented source

Virgo

Virgo+

584 Mpc145 MpcBH-BH

114 Mpc30 MpcNS-NS

Virgo+Virgo

Coalescing binaries rates increased by ~ 30-100


Virgo+ status and plan• Status of the project:- approved by CNRS and INFN- new mirror substrates purchased- infrastructure for fused silica fiber production and mirror assembly ready- laser amplifier to be delivered next fall- new electronics being developed

• Plan- test prototype of fused silica suspension in 2007- start upgrade after extended Virgo data taking- shut down for upgrade ~ 2008


Toward Advanced Virgo• Sensitivity goal: ×10 better than Virgo (similar to Advanced LIGO)

• Expected area of improvement:- High power lasers and injection optics- Laser beam geometry- Interferometer optical configuration- Signal recycling- Mirror coatings and shape- Monolithic suspensions- Larger mirrors

• A possible sensitivity

• Envisaged timeline- by 2009: R&D and final design- 2009-10: engineering> 2010: construction


• The role of WG3:- Animate discussions about available technologies to improve interferometer sensitivity

e.g. Virgo-LIGO thermal noise workshop held in Cascina last fall- Triggered participation of GEO scientists into the Advanced Virgo design

Virgo-GEO MOU signed in 2006

- Support participation of GEO scientists to Advanced Virgo working groups

Advanced Virgo and WG3


Toward Advanced Virgo design• Most recent outcome of Advanced Virgo working group:

“Guidelines for Advanced Virgo R&D”, transmitted to CNRS and INFN

• EGO just launched an R&D program to support the preparation of Advanced Virgo along the lines traced in “Guidelines for Advanced Virgo R&D”

• Next milestone: preliminary Advanced Virgo design and costing by the end of 2007


WG3 implementation plan

- Finalization ofthe ‘White book’- Discussion of‘White book’ withfunding agencies- Writing of finalreport

- Evaluation ofcompatibility amongproposed long-termscenarios- Draft of a credibleplan for a Europeannetwork ofgravitational wavesdetectors at the 2012horizon

- Presentation of shortterm plan to thefunding agencies- Definition of realisticobjectives for newgeneration antennas- Definition ofrequirements andneeds for possible nextgeneration antennas

- Evaluation of proposedshort term improvements- Preparation of adocument describing aproposition for shortterm improvements.

- Working groupsetup- Definition of a listof possible short-termimprovements

YEAR 5(2008-09)

YEAR 4(2007-08)

YEAR 3(2006-07)

YEAR 2(2005-06)

YEAR 1(2004-05)

• Phase I: identify and propose short term improvements of existing detectors

• Phase II: study new generation detectors


• Need to improve sensitivity at low frequency (1Hz – 10 Hz)- most interesting physics is there- mergers of intermediate mass black holes at cosmological distances, stochastic background, galactic neutron stars, ….

• Advanced interferometers will reach the limit of present infrastructures: seismic noise- acting on mirror suspensions- acting directly on mirrors via gravity gradients

• Need to reduce seismic noiseGo underground

• Other advantages:- No wind- Easier to build longer arms (10 km?)- Easier to imagine longer suspensions (100 m?)

Beyond Advanced Virgo

Seismic noise Gravity gradient noise


• A possible design

3rd generation interferometer

Upper experimental hall

Credit: R.De Salvo

50-100 m well to accomodatelong suspension for low frequency goal

Ellipsoidal/spherical cave fornewtonian noise reduction

10 km tunnel

Rüdiger, ‘85


3rd generation interferometer• And then need to reduce thermal noise

Go cryogenics

• One of the goal of the STREGA JRA within ILIAS

• Other third generation ITF keywords:- squeezed light- massive mirrors- ….

• Sensitivity goal: ×10 better than Adv ITF Enter the 10-25 scale

• WG3 meetings now focus on this subject

• Working on a design study proposal within FP7 (with participants from all the main existing projects and institutions CNRS, INFN, PPARC, MPI, Nikhef, ….)


• Existing detectors are in the process of testing theoretical upper limits• Still space to improve their sensitivity• Further improvements will need a new facility (FP7)

• An exciting experimental program in front of us• WG3 of ILIAS-GWA contributing to the definition of this program

Conclusions

n5/wg3: future gw detectors in...

Documents