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Gravitational Waves:Current and future experiments
Kazuaki Kuroda
ICRR, The University of Tokyo
TAUP2011 @ Munich5-9, September
Related talks in parallel session yesterday
• Well-balanced introductory talk by Laura Cadonati (U Mass)
• Noise and signal by Giovanni Andrea Prodi (U Trento)
• LCGT status by Shinji Miyoki (ICRR, UT)
• Starving field of GW by Bruce Allen (MPI, Hannover)
• GW from rotating star by Andrzej Krolak (Inst. Math, Polish Academy of Science)
• ET by Harald Lueck (MPI, AEI)
• Bar detector response to cosmic particle by Francesco Ronga (INFN)
• A laser gryo by Angela Virgilio (INFN-Pisa)
• Gravity waves are produced dynamic motion of massive terrestial objects. Here consider the radiation by simple rotating equal masses
• Radiation formula of EM Luminosity = (2/3c3) e2a2
• Radiation from Mass dipole moment = 0
• Radiation of mass quadrupole moment is the lowest term of gravity wave
• Gravity wave luminosity = (G/5c5)( I )2
I = Ijk Ijk , Ijk= ΣmA(xAjxAk-1/3δjkrA2)
Ijk: the reduced quadrupole moment
Introduction: Generation of Gravity wave
Introductory talk by Laura
& spinning star by A Krolak
Introduction: Target GW Sources
• PSR B1913+16
• PSR B1534+21
• PSR J1141-6545
• PSR J0737-3039
• PSR J1906+0746
Existing neutron star binaries in our Galaxy
1. Coalescence of neutron star binaries2. Coalescence of black hole binaries3. Core collapse of massive stars4. ・・・・・
msec
chirp signalcoalescence
quasi-modeoscillation
-300Hz -1kHz
Intro: Detection of gravity wave by resonant antennae
J. Weber started to make practical detector in late of 1960s
Gravity plane wave
0 0 0 00 h11 h12 00 h21 h22 00 0 0 0
hij=
Disk type: Resonant frequency could be changed by making slits
Bar type: Resonant frequency was determinedby the length of the bar
Tidal force of gravity wave causes elastic vibration of eigen mode, which can be detected bysensitive transducer. Thermal noise of vibration is reduced by lowering the temperature.
GR is being tested as in Angela’s talk
61022 1Hz
Peak strain sensitivity
7.21022m Hz
Unprecedented: World Record
Displacement sensitivity
NAUTILUS - INFN Frascati
Vp
Antenna
M
Cd
Rp
Vp
Antenna
M
Cd
Rp
Readout: Resonant capacitive transducer &Dc SQUID amplifierPhys.Rev.Lett. 91:111101, 2003.
106Msunc2Detectable: Galactic burst with
converted in GWs
By the courtesy of Eugenio
Nautilus as acoustic particle detector
Interaction of a particle with a bar: ionization energy lost is converted in thermal heating and therefore pressure wave. The detection mechanism is quite simple, no threshold in β “calorimetric measurement”
Upper limit for nuclearite flux from the Rome GW resonant detectorsPhys.Rev. D47:4770-4773, 1993
Cosmic rays observed by NAUTILUSPhys.Rev.Lett. 84:14-17, 2000.
Detection of high energy cosmic rays with NAUTILUSAstropart.Phys. 30:200-208, 2008.
Nautilus is able to detect energy releases as low as 10-7 eV (10-26 J) by measuring the excitation of the longitudinal mode ofVibration.
Cosmic rays: observedExotic form of matter: observable
Nautilus is equipped with streamer tubesparticle detectors
See presentation file of Francesco
Intro: Detection of gravity wave by Interferometer
z
wave propagation
Photo detector
Mirror XMirror Y
Beam Splitter
Laser
Metric perturbationgij=ηij + hij hij=
0 0 0 00 h11 h12 00 h21 h22 00 0 0 0
Gravity plane wave
Light speed of propagation differs for each arms of Interferometer ΔL/L ≃ h/2
Phase difference at BS is detected by power change of the photodiode
is detected by
Michelson type laser interferometer
Typical amplitude h ~ 10-22
This is also shown by Laura using Fabry-Perot Interferometer
Intro: Noise of Current Interferometers
Anti-vibration system
Seismic noise
Mirror Substrate thermal
Coating thermal
Suspension thermal
Photon counting
Laser pressure
Frequency
sen
sitivity
10 100 1000
Sensitivity limited only by fundamental noise sources
seismic
Suspension thermalMirror thermal
Laser powerBlood sweat and tears in
reducing noise is summarized
in Giovanni’s talk
Current detectors in the World
Adv. LIGO
(under construction)
LCGT (under construction)
LIGO(I) Hanford
LIGO(I) Livingston
GEO HF
Virgo
LIGO-Australia (budget request)
Adv. Virgo (under construction)
ET (planed)
A network of detectors is indispensable to position the source.
TAMA/CLIO
AURIGA
Nautilus
Necessity of more sensitive detectors
• The present detectors such as LIGO (USA), VIRGO (French-Italian), GEO (Germany-England) and TAMA/CLIO (Japan) have sensitivity to catch GW events occurring at most 30Mpc. Since the occurrence rate of the coalescence of BNS is estimated to be 10-5 for matured galaxy per year and there are 0.01 galaxies for 1 cubic Mpc, it takes roughly 300 years to catch one event.
• Advanced detectors are under construction to detect events occurring at around 200Mpc, which makes possible to detect at least a few events of BNS coalescence in a year.
LIGO project and Advanced LIGO
One interferometer
with 4 km Arms,
One with 2 km Arms
One interferometer
with 4 km Arms
Initial LIGO timelineConstruction started in 1994First data-colletction (S1) 2002Design Sensitivity Achieved 2005Enhanced LIGO (S6) 2009-2010
Sensitivity improvement in Initial LIGO (2002-2007)
Efforts of Enhanced LIGO
Increased laser power10 W -> 30-35 WEOMFaraday IsolatorThermal lensingRadiation Pressure
DC readoutOMCDetector in Vacuum
Estimation of Noise
Advanced LIGOScope of Advanced LIGO
Monolithic suspension
TCS performance
New isolation system
Virgo projectItalian-French Collaboration
Construction completedin 2003
Final configuration in 2005Data-taking started in 2006(VSR1) ended in 2007
with LSCVirgo+ (VSR 2, S6) ended
in 2010
Typical features:● Located at Cascina in
Pisa● 3km baseline length● Fabry-Perot Michelson
Interferometer● Ultra-low frequency
isolation system
Low frequency isolation system characterizes the Virgo interferometer
8m
tal
l
Sensitivity Improvement
• High power laser: 25 W (Virgo+) -> 200 W
– Input mode cleaner
– Improved TCS (thermal compensation system)
– Control electronics
• New optics
– Heavier mirror mass
• Monolithic fused silica suspension
• Upgraded seismic isolation system
From Virgo+ to Advanced Virgo
Current design of Advanced Virgo
40 kg test masses
large spot size
dual recycled
DC readout
high powerfiber laser
1) Funded by INFN/CNRS (and contributed by NIKHEF) in Dec 20092) Procurements and parts construction started3) Installation to start at the end of the year4) Acceptance in 2015
GEO600 project
GEO is an observing instrument and a prototype for new technologies'Advanced techniques' of GEO:
Monolothic suspensions (since ~10 years) Electro-static actuatorsSignal recyclingSqueezing (since 2010)
Power Recycling Mirror T=0.09%
Signal Recycling MirrorT=10%
GEO optical Layout
Output modecleaner
End mirrors with Electro-staticactuators
DC readout
Squeezer Installation in May 2010
Squeezing light is introduced from signal port to reduce shot noise. 3.5dB Improvement has been achievedand 4dB more is expected in 2011
22
GEO600 Science Times since 2006
LSC-s5: 421 days, 90% (duty factor in 24/7)
Astrowatch Nov 2007 - July 2009:
522 days, 86%
LSC-s6d: 60 days, 88%
VSR4/S6e, Virgo/GEO summer run 3.June – 5.September 2011
85%
GEO-HF sensitivity
Frequency [Hz]Strain
[
1/sqrt(H
z)]
Commissioning -2011Squeezing: automatic
alignment, 4+dBIntermediate freq. noise
reduction.30W main laser, new IMC
mirrors, thermal compensation for BS,
->circulating light power increase
Data taking -2012night/weekend modeLonger periods / higher
duty cycle as GEO-HF progresses
Next Step
TAMA/CLIOTAMA is a 300 m baseline Fabry-Perot MichelsonInterferometer with power recycling and achieved the best sensitivity and long observation run earlier than any other long baseline interferometersby 2000.
R&D are being conducted for advanced interferometertechniques for LCGT.
TAMA in Mitaka, Tokyo
CLIO underground at Kamioka
CLIO is a 100 m cryogenic locked Fabry-Perot interferometer placed underground at Kamioka mine.
Thermally limited sensitivity was achieved in 2009 by cooling mirrors down to 10 K. It is a test bench for cryogenic part of LCGT.
Location of LCGTLCGT is planed to be built underground at Kamioka, where the prototype CLIO detector is placed.
Full explanation was given by Shinji
LCGT design Power recycled Fabry-Perot Michelsoninterferometer with Resonant-side-bandextraction
75 w
Double floor isolation systemMounted above cryostat
Cryostat for main mirrors
Main mirror
PTC Heat link
R&D results by TAMA and CLIO for LCGT
TAMA in 2008 (improved after installation of SAS)300 m arm length
CLIO at cryo temperature, 2010/3/7100 m arm length
CLIO limit by roomtemperature
LIGO4 km
LCGT design, 3 km
LIGO-AustraliaA set of Advanced LIGO is planed to be installed at Gingin north of Perth in Western Australia (AIGO project of ACIGA consortium, InDIGO, China)
*) Funding is being requested to Australian government , the result of which will be disclosed, soon.
*) NSF has approved
If realized, the positioning accuracy of sources becomes much improved
LIGO-India • InDIGO (since 2009)Roadmap workshop in
Delhi at University of Delhi, December 2010
• Funding for 3m prototype interferometer at the Tata Institute for Fundamental Research
• Created an Indo-US Center for GWs, funding awarded
• Proposing to participate in LIGO-Australia as a major partner (15%)
• Possible alternative of the case of disapproval of LIGO-Australia
Einstein Telescope Given by Harald
GWIC roadmap of ground based detectors
Will be organized as LIGO-Australia or LIGO-India
L I S ALISA is a joint NASA-ESA space mission of interferometer to see gravity wave events more remotely and more frequently.
- Frequency band: 0.03mHz-0.1Hz, abundantscience objects
- 5 million km baseline length- LISA Pathfinder will be launched in 2013 for the
test of technologies for LISA Preparation of LISA Pathfinder
Orbital motion of LSIA satellites
DECIGODECIGO: Fabry-Perot space interferometer works in frequencies from 0.1 – 10 Hz
Objective:1)Direct observation of the beginning of The Universe2) Measuring the acceleration ofthe Universe
1000 km
DECIGO Pathfinder tests the technologies required to realize DECIGOWill be nominated by the small science spacecraft series run by JAXA/ISAS
AstroWatch recommended by GWIC
• AURIGA and NAUTILUS in operation as an "astrowatch" until LIGO/Virgo resume operation after upgrade
• GEO-HF enters this operation as soon as possible
AURIGA & NAUTILUS continously on the air > 95 %with noise close to Gaussian
(~ 20 outliers/day at SNR>6)until LIGO/Virgo resume
operation
burst sensitivity hrss ~ 10-20 Hz-1/2 or hburst ~ 2x10-19
AUNA: “astrowatch” of AURIGA & NAUTILUS
excercise in recovering injected bursts of 8•10-5 Msolar with coherent wavebursts analysis;
bursts of random ploarization randomly injected in the Galaxy accordingly to the star density;
injections over 1day of AUNA data
detection efficiency vs distanceDistribution in the Galactic plane of the injections (colour) and of the recovered
signals (black)
Summary
• By the first generation detectors of LIGO, GEO, Virgo, TAM/CLIO, we are not in success to catch GW
• This is represented as “starving”, suffering from lack of signal, compared with wealthy astronomers by Bruce Allen
• By two talks in yesterday parallel session; EM follow-up by Marica Branchesi (U Urbino) and first joint analysis with ANTARES by Irene Palma (MPI, AEI) show dynamic approach for signal
• This situation is rescued only by operating more sensitive detectors such as Advanced LIGO, Advanced Virgo, and LCGT, which is firmly confirmed by the previous talk of Alan Weinstein
• We aren’t spiritually starving. We hope that ET will be funded soon and LISA heads along its original strategy
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