lcgt project status
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LCGT Project Status
EGO-ICRR Meeting4 October 2011
@ University of TokyoSeiji Kawamura (ICRR)
Objectives of LCGT
• Detect gravitational waves together with Virgo and LIGO for the first time
• Establish Gravitational Wave Astronomy• Establish multi-messenger observations
between GWs and Electromagnetic waves/Cosmic rays
Expected GW sources• Neutron star binary
coalescence– correlation with GRB
• Black hole binary coalescence
• Black hole ringdown• Supernovae– Correlation with Neutrino
• Pulsar• Early universe• Unknown
Key Features of LCGTUnderground Cryogenic mirrors/
suspensions
These are essential features for the 3rd GW detectors such as ET.
Underground Site
We are here.
Ground motion in Kamioka mine
Advantage of Underground Site
• Not only linear effect• But also nonlinear effect
Smaller low-frequency motion of mirror Lower gain of control system necessary Lower in-band noise imposed by control system
Sensitivity Comparison
Hz
Disp
lace
men
t spe
ctru
m m
/RHz
20m prototype was moved from Tokyo to Kamioka in 1998.
@ Tokyo
@ Kamioka
Cryogenics System
Baffles Thermal Shield Pulse Tube Cryocooler
Inner Wall (8K)Platform (14 K)Upper Mass (15 K)Mirror (20 K)Flexible Heat Link
Sapphire Mirror
Sapphire mirror at 20 K• Transparent at 1064 nm• Low thermal noise– High Quality factor at 20 K
• Low thermoelastic noise– High thermal conductivity at 20 K– Low thermal expansion coefficient at 20 K
Seismic Attenuation System (SAS) for LCGT
Tunnel (2nd floor)ChamberInverted Pendulum
GAS Filter(invented by DeSalvo)
Tunnel (1st floor)ChamberMirror SAS was designed based on
the Virgo SA.
Goal Sensitivity of LCGT
External Review
• Feb. 28 – Mar. 4, 2011 @ICRR• Almost all the subsystems were reviewed• Review items:– Requirements– Design – Schedule– Prototype test plan– Etc.
ReviewersName Affiliation Remarks
Stefan Ballmer LSC/ Syracuse University
Alessandro Bertolini LSC/ Albert-Einstein-Institut Hannover
Raffaele Flaminio Virgo/ Laboratoire des Matériaux Avancés
Andreas Freise GEO/ University of Birmingham
Warren Johnson LSC/ Louisiana State University
David Ottaway ACIGA/ University of Adelaide
Benno Willke GEO/ Leibniz Universität Hannover
Michael E. Zucker LIGO-Lab/ Massachusetts Institute of Technology Chair
Seiji Kawamura LCGT/ ICRR, NAOJ Chief of secretariat
Masaki Ando LCGT/ Kyoto University Deputy chief of secretariat
Report
• We obtained report on March 10, 2011• 12 pages• Consists of:– Executive summary– Recommendations to management– Recommendations to each subsystem
Executive Summary 1
focusing interferometer noise optimization (and corresponding astrophysics goals) to capitalize on the unique advantages of the underground site and cryogenic operation
Bandwidth working group (led by K. Somiya) was convened to discuss this. It turned out that shifting the frequency band lower will not gain significant advantages.
Executive Summary 2
establishing a strong Systems group to insure subsystem interfaces and design goals are properly distributed, and sufficient, but not excessive
Systems Engineering Office has been created.
Executive Summary 4 & 5
wherever feasible, employing (or at least starting with) established, tested component designs requiring minimal modification; proceeding rapidly toward integrated system testing (e.g., through enhanced scope for the iLCGT phase) to minimize the risk of late surprises
Roadmap working group (led by M. Ando) was convened to discuss this. We decided to employ a simple isolation system for iLCGT and meanwhile to develop SAS at the site.
Program Advisory Board
• Jun. 21 – 22, 2011 @ICRR• Review items:– Management– Schedule– Design– Etc.
ReviewersName Affiliation Remarks
Masanori Iye NAOJ, Extremely Large Telescope Project Office
David McClelland ACIGA, ANU
Benoit Mours Virgo, LAPP Annecy
Takashi Nakamura Department of Physics II, Kyoto University
Bernard Schutz GEO, AEI, Potsdam
Gary Sanders Thirty Meter Telescope project
Akira Yamamoto KEK, Cryogenics Science Center
Stan Whitcomb Caltech Chair
Report• We obtained report on August 30, 2011• 6 pages• Consists of responses to the following points:
– If the management and organization of the project are OK.– If the construction status & plan are OK.– If the scientific goals are reasonable.– What should be improved in the LCGT construction?– Whatever the advice for this project.
• Actions:– We have started discussing possible actions to the report.
Schedule of LCGT2011 2012 2013 2014 2015 2016 2017
bLCGTiLCGT
Observation
iLCGT bLCGT
Temperature Room Cryogenic
Vibration isolation Stack and triple pendulum SAS
Interferometer Fabry-Perot Michelson Resonant sideband Extraction
Organization of LCGTLCGT Council Director
(Kajita)Program
Advisory Board
Systems Engineering Office(Kawamura, Ando,
Miyoki, Somiya)
Executive Committee( Nakatani (PM), Kuroda, Ohashi, Kawamura, Mio,
Ando)
Executive Support
DATA Analysis
Cryogenics
Input/Output Optics
Tunnel Facility Vibration isolationVacuum
Mirror
Laser
Main interferometer
Auxiliary optics
Digital system
Geophysics Interferometer
Analog Electronics
Subsystem
Joining the worldwide GW network
Advanced Virgo
LCGTAdvanced LIGO GEO-HF
LCGT will join the world network of gravitational wave detectors, with full reciprocal sharing of data with the Virgo collaboration, the LIGO Collaboration and the GEO600 Collaboration at a time determined by mutual agreement of all parties - LCGT, Virgo, LIGO, and GEO.
LCGT in network
L/H+L/L+V 50% L/H+L/L+V+LCGT 50%
B. F. Schutz
LIGO(H)+LIGO(L)+Virgo
Coverage at 0.5 M.S.: 72% 3 detector duty cycle: 51%
LIGO(H)+LIGO(L)+Virgo+LCGT Max sensitivity (M.S.): +13% Coverage at 0.5 M.S.: 100% 3 detector duty cycle: 82%
Dawning of Gravitational
Wave Astronomy is
near!
Illustration:
Sora
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