Status of gravitational wave
detection in Japan
Koji Arai(National Astronomical Obsevatory of Japan)
on behalf of
TAMA Collaboration and LCGT Collaboration

LCGT Projectl Japanese advanced interferometer for GW detection- 3-km Fabry-Perot Michelson interferometer- with power recycling- resonant sideband extraction (RSE)- laser power of 150W

l Sapphire test masses- cooled up to 20K- suspension point interferometer (SPI)l Sited at Kamioka mine

- underground mine
- two independent interferometers to reject fake eventsl Main target ~ the coalescence of BNS- expected 1.2-27.8 events per year
(C.L. of 95% for 1.4Msolar with S/N=10)

Optical configuration of LCGTl Power recycling gain of 10l Signal gain of 10 by RSE (fc=200Hz)

200kW

150W

90W

50W

500W

200kW

Two detector at a place

SPI: Suspension Point Interferometerl A sort of active isolation system

Attenuate vibrations introduced through heat links

l Assist lock acquisitionl Actuators with smaller range for the test masses=> smaller noise

Upper FP

Rigid barconsidered as

Lower FPLower FP

Suspension and vacuum system
SAS: three vertical filterswith inverted pendulum

Outer shield of cryostat
Heat links connectedto heat anchor
onthe inner shield

Suspension Point
Interferometer (SPI)
Sapphire fiber

Test mass

LCGT sensitivity
To be limited only by quantum noises in the obs. band

Technical foundations of LCGT
Cryogenictechniques

CLIO

1997-2002@KEK, ICRR

2002-@ICRR Kamioka
100m Cryogenic Locked FP

LISM

Cryogenic
Interferometer

1999-2002@ICRR Kamioka
20m Locked FP
Interferometer
Techniques

LCGT

TAMA

1995-@NAO
300m FPMI

TAMA-SAS

1998@u-tokyo, NAO

AdvancedTechniques

RSE

1998@NAO

SPI

1999@u-tokyo

100W
Laser

2002@u-tokyo

TAMA300l Laser interferometric GW detector
with arm length of 300m
Site: National Astronomical Observatory of Japan,(Mitaka, Tokyo)l Objects of the project
To develop a detector
capable to detect GW eventsin nearby galaxies.
To establish necessaryinterferometer techniquesfor LCGTl Designed sensitivity
hRMS = 3 x 10-21@300Hz (BW300Hz)

Progress of TAMA300 development
Recombine I

Mode Cleaner
97/4 - 97/12

98/5 - 99/1

300m
FP cavity

Mode Cleaner+ 10W Laser
98/1 - 99/1

300m
FP cavity

1995

Project started

1997

Arm cavity locked

1999

FPMI operation
DT1(11h)DT2(31h)DT4(167h)DT6(1038h)
Power Recycling

2000
2001

10W Laser

2002

Recycling I
01/10 - Present10m
Mode Cleaner

One Arm

Recombine II
Recombine III

97/8 - 98/4 2003

99/2 - 00/6
00/9 - 01/9

Coincidence Run
with LIGO(S1)and GEO600

DT8(1158h)with LIGO(S2)2003~4DT9with LIGO(S3)and GEO600
Full Automatic Operation
2004~5 Noise hunting
TAMA-SAS

Observation runs: DT1~DT9
Data Taking

Objective

Observationtime

Typical strainnoise level

Total data(Longest lock)

DT1

August, 1999

Calibration test

1 night

3x10-19 /Hz 1/2

10 hours(7.7 hours)

DT2

September,
1999

First Observation run

3 nights

3x10-20 /Hz 1/2

31 hours

DT3April, 2000

Observation withimproved sensitivity

3 nights

1x10-20 /Hz 1/2

13 hours

DT4Aug.-Sept.,
2000

100 hours
observation data

2 weeks(night-time operation)

1x10-20 /Hz 1/2(typical)

167 hours(12.8 hours)

DT5March, 2001

100 hours observation
with high duty cycle

1 week(whole-day operation)

1.7x10-20 /Hz 1/2(LF improvement)

111 hours

DT6Aug.-Sept.,
2001

1000 hours
observation

50 days

5x10-21 /Hz 1/2

1038 hours(22.0 hours)

DT7Aug.-Sept.,
2002

Full operation with
Power recycling

2 days

DT8Feb.-April.,
2003

1000 hours
Coincidence (S2)

2 months

3x10-21 /Hz

1157 hours(20.5 hours)

DT9Nov.-Jan.
2003-2004

Automatic operation
Coincidence (S3)44 days(night-time inweekdays)-21557 hours(28.1 hours)

25 hours

2x10/Hz

More than 3000 hours data

Noise budget
Displacement noise level of TAMA300-610-7dL- displacement
Laser frequency noise
Laser intensity noise
Detection+Shot noise
Shot noise
Detection noise
mirror thermal noise Q=3e6suspension thermal noise Q=5e5dl- feedback noisedl+ feedback noisedL- filter noise
Alignment noise
Seismic noiseElectronics noise (matrix)
Oscillator Amplitude Noise
Oscillator Phase Noise

10-8

1/2

Displacement noise [m/Hz ]

10-9

10
10-10

10-11

10-12

10-13

10-14

10-15

10-16

10-1710-18

10-1910-20

100

10

110

2

10

3

Frequency [Hz]104105SAS: Seismic Attenuation Systeml Development of SAS
Collaboration with
Caltech and Universita di Pisa

l Installation
05 summer:
1 SAS for one of the end mass
05 autumn/winter:
The other 3 SASsl TargetTo improve seismic-related noise
direct or indirect noise couplings
To stabilize the IFO operation
To ease lock acquisition

SAS: Seismic Attenuation Systeml Inverted Pendulum
Horizontal isolation
Resonant frequency:
Currently 70-80mHz
To be 30mHzl MGAS
Vertical isolation
Resonant frequency:
To be 0.4~0.5Hz

Filter Zero
VerticalPre-Isolator

Standard
FilterMonolithic
GAS
MiniGAS
Passive Damper
Recoil MassMirror

InvertedPendulum

MirrorSuspension

1/2

Displacement noise [m/Hz ]SAS: Seismic Attenuation System10-410-5

Test@3mFP10-6Displacement

10-7

10-8

10-8 m/Hz1/2->-9

10-11 m/Hz1/2

10-10

10-11

RMS Velocity

SAS test at 3m FP (Univ. of Tokyo)
IP damping On, in the air
IP damping Off, in vacuum
TAMA Displacement

10-12

10

3.7 µm/s->
0.3 µm/s-13

10Electronics
noise

-14

10-15

10-2

10-1

10010
Frequency [Hz]101102

Expected: lower seismic/alignment noise,easier lock acquisition

Electronic noisel dL- servo chain

Coil DriverServo(emphasis) FilterPD

AttenuatorLong Cable (~20m)

Demodulator

Matrix(de-emphasis)

1/2

Displacement noise [m/H z ]Displacement noise level of TAMA300 (2005/6/3)

10

2005/06/03
Matrix noiseElectronic noise coupling
after the servo filter

-16

10-17

10-18

10-19

10

Electronic noise /noise couplingclose to limit
the sensitivity=> currently trying
emphasis/de-emphasis
filters

22

3

4

5

6

7

8

9

10

3

2

Frequency [Hz]Summaryl LCGT: Japanese future interferometer for GW detectionl Interferometric GW detector TAMA300
To establish interferometer techniques for LCGTl Current efforts focused on noise huntingl SAS: Seismic Attenuation System
Vibration isolation from 0.1Hz region
Installation work on goingl Electronics noise
Trying to arrange the gain distribution