Gravitational Wave Astronomy by KAGRA Seiji Kawamura (ICRR, UTokyo) - - PowerPoint PPT Presentation

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Gravitational Wave Astronomy by KAGRA Seiji Kawamura (ICRR, UTokyo) - - PowerPoint PPT Presentation

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Toyama International Workshop on Higgs as a Probe of New Physics 2015 Feb. 13, 2015 University of Toyama, Toyama, JAPAN Gravitational Wave Astronomy by KAGRA Seiji Kawamura (ICRR, UTokyo) 1 on behalf of the KAGRA collaboration

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Gravitational Wave Astronomy by KAGRA

Seiji Kawamura (ICRR, UTokyo)

  • n behalf of the KAGRA collaboration

Toyama International Workshop on “Higgs as a Probe of New Physics 2015”

  • Feb. 13, 2015

University of Toyama, Toyama, JAPAN

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JGW-G1503308-v2

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Outline:  Gravitational wave and its detection  Review of KAGRA  Current status of KAGRA  Summary

2

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  • Einstein Equation
  • For a small perturbation ‘h’, a wave

equation is derived

Gravitational wave

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Gravitational wave

  • Predicted by A. Einstein
  • Not yet detected
  • Tidal space distortion of 10-22
  • Propagates at the speed of light
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5

GW exists!

Taylor et al., ApJ.345(1989) p435

 PSR1913+16 found by Hulse

se and Taylor

 Period of rotation decrease

ses s by GW GW

 Nobel prize in 1993

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1.3 Ms – 1.6 Ms (Equation of state: APR4)

Hotokezaka, et al. (Kyoto Univ, and others)

Simulation of neutron star binary coalescence (1)

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1.2 Ms – 1.5 Ms (Equation of state: APR4)

Hotokezaka, et al. (Kyoto Univ, and others)

Simulation of neutron star binary coalescence (2)

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380,000 year (Recombination)

Electromag agnet etic wave

1 sec (First atoms) Neutrino

Observation of the beginning of the Universe

The beginning of the Universe

13.7B year (Now)

Gravitation

  • nal wave

10 -43 sec (Planck epock）

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Gravitational wave detector

Laser Interfering light Beam splitter Mirror Mirror Lens Screen

Gravitational waves

The mirrors and beam splitter are suspended.

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Large-scale interferometer

Laser Photodetector Mirror Mirror Laser Photodetector Mirror Mirror

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Large-scale interferometers in the world

LIGO (4 km) LIGO (4 km) VIRGO (3 km) GEO (600 m) TAMA (300 m) CLIO (100 m) KAGRA (3 km)

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KAGRA

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Mozumi Entrance Shin-atotsu Entrance

Location (Kamioka)

Super-Kamiokande CLIO

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◎Tokyo Kamioka◎ Toyama airport 40min. by car

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Key features

  • f KAGRA

Underground Cryogenic Mirror

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Technologies crucial for the 3rd-generation detectors; KAGRA can be regarded as a 2.5-generation detector.

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Two technologies + one

Undergro round nd Cryogenic c Mirror Resonan ant Sideband Extraction Strain Frequency

Typical sensitivity of the 1st generation detectors

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Ground motion in Kamioka mine

Kashiwa Kamioka

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Further seismic isolation is still necessary

Vibration of mirrors: 10-11 mHz-1/2 10-18 mHz-1/2 @10 Hz

Should be improved by 7 orders of magnitude

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Vibration isolation system

2nd floor Inverted pendulum Geometrical antispring (GAS) filter Multi-stage pendulum (with GAS filter) 1st floor Another pendulum (with GAS filter) Mirror suspension

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Two-layer structure to avoid the resonances of the tall structure.

GAS filter

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Cryogenics System

Main Beam Cooling 8K shield Cooling Cryo-Payload Duct Shield 400kW 4W? ~1W Cryostat 80K shield 8K shield 2 units 80K PTC with Vibration reduction 2 units 300K Radiation

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Platform (14 K) Upper Mass (15 K) Mirror (20 K)

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Sapphire Mirror

Two Sapphire substrates have been delivered. (Φ220mm, t 150mm, c-axis)

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Resonant Sideband Extraction interferometer

Fabry-Perot arm cavity: Increase the effective arm length

  • > Increase the GW signal

Power recycling mirror: Increase the effective power

  • > Improve the shot noise

Signal extraction mirror: Extract GW signal before cancellation

  • > Optimize the quantum noise

Detuned for the best NS-NS inspiral range

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Ultimate Sensitivity Limit of KAGRA

Beating the standard quantum limit

Duty factor: > 80%

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Expected event rate for NS-NS coalescence

Inspiral range: 176 Mpc (the same definition as LIGO/Virgo) Assuming Inspiral rate per galaxy: 100 Myr-1 Expected event rate: 10 yr-1 We could reveal the mechanism of Short GRB with -ray observation group.

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Other GW sources

  • BH-BH coalescence: e.g. 20 M at 2 Gpc,

0.41000 events per year

  • Quasi-normal mode of BH: e.g. 100300 M at

3 Gpc

  • Supernova: Hopefully 1 Mpc, 1 event per 30

years

  • Pulsar: Crab and Vela, possibly other invisible

pulsars

  • Beginning of the Universe: non-standard model
  • Unknown: Nature likes to surprise us.
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Schedule of KAGRA

2010 2011 2012 2013 2014 2015 2016 2017 2018

Calendar year Project start Tunnel excavation initial-KAGRA baseline-KAGRA Observation iKAGRA obs.

  • Adv. Optics system and tests

Cryogenic system

iKAGRA

 Michelson interferometer  Room temperature  Simple seismic isolation system

bKAGRA

 Resonant sideband extraction  Cryogenic temperature  Advanced seismic isolation system

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Shin-Atotsu entrance (2014.9.26)

片岡優氏撮影
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1st floor of central area （2014.7.4）

東京大学宇宙線研究所広報室
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2nd floor（2014.7.4）

東京大学宇宙線研究所広報室
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Installation of beam tubes（2014.10.23）

片岡優氏撮影
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Clean booth and sound-proof room （2014.10.31）

麻生洋一氏撮影
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Summary

  • KAGRA has cryogenic and underground GW

detector (2.5-generation).

  • We plan to build KAGRA in two steps: iKAGRA

and bKAGRA.

  • We are installing iKAGRA now.
  • We plan to have an observation with iKAGRA

at the end of 2015.

  • We plan to start observation run with

bKAGRA at the end of 2017.

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