TAMA300 interferometerl Laser interferometer GW detector- Arm length: 300m
- Location:
National Astronomical Observatoryof Japan (Mitaka, Tokyo)

l Purposes- Development of the detector
capable to catch GW eventsin nearby galaxies- Establishment of interferometer
technologies for LCGT

300m

300m

Progress of TAMA300
1995-1997

Facility/Vacuum system construction

Recombined Interferometer
1999-2001
6 times of observation runs
(Total 1370 hours)
Recycled Interferometer
2001
Implement of power recycling
2003-2004
3 times of observation runs
(Total 1740 hours)
Seismic Attenuation System (SAS)2005
Start installation of SAS2007
Full interferometer lock with SAS2008
Sensitivity improvement

Interferometer
configuration
300m
Fabry-Perot
Cavity10-Winj.-locked
Nd:YAG
10-m
laser
ModeCleaner

OpticalLevers

Recycled
Fabry-Perot
Michelson
interferometer

Wave Front
Sensors
Lengthsensors

SASfor test masses

Current focus
l Establishment of detector operation with SAS
Replacement of the vibration isolation system
pneumatic
active isolator+ stack+ double pendulum

inverted pendulum+ vertical filter+ multiple pendulum

To realize the improvement- Optimization of SAS control- Optimization of interferometer control- Application of digital control system=>Enables the complex servo system=>High level automatization of the operation

Seismic Attenuation Systeml Structure of SAS
Multiple pendulum suspended from IP
IP top

MGAS filter(MonolithicGeometric Anti-Spring)

invertedpendulum(IP)platform
double pendulumwith recoil mass

Seismic Attenuation Systeml Vibration Isolation
Passive isolation with soft springs + active damping
Tortional

Vertical

f~40mHzf~50mHz

Tortion Pendulum
Inverted Pendulum
f~500mHz

Horizontal

Inverted Pendulum
f~30mHzMultiple Pendulum
f~650mHz

MGAS Filter
MiniGAS Filter
f~1.5HzSeismic Attenuation Systeml Active Control of SAS

Local control stabilize the mirror motion=> to enable lock of the interferometer

Local control
IP Position

Sensor: LVDT
Bandwidth: ~60mHz

IP Inertial damping

Sensor: Accelerometer
Bandwidth: 60m~2Hz

Global control
IP Position

Bandwidth: ~10mHz

Plat form

Bandwidth: ~10mHz

Test mass (angular)
Bandwidth: <3Hz

Tortion damping

Sensor: Photo Sensor
Bandwidth: 40mHz

Test mass servo

Sensor: Optical Lever
Bandwidth: ~2Hz

Test mass (Length)
Bandwidth: <1kHz

Performance of SASl Low frequency Legth Fluctuation of 300-m arm

Displacement fluctuation [m/Hz1/2] or RMS [m]Comparison with the previous suspension system=> improvement above 0.1Hz was confirmed-510OldSuspension-610SAS
Inline arm
Perpend arm-710-810-910-210-1

10010

110

Frequency [Hz]

Performance of SAS●Test mass angular motion (Free run)

1/2

Angular Fluctuation [rad/Hz ] or RMS [rad]locally measured by an optical leverYaw-510-610Pitch-710-810

NM2 Angular motion ~ Free Run
Pitch
Yaw-910-210-1

10010110 Frequency [Hz]Fluctuation Power concentrated on the low freq
θRMS ~ 30nrad (f>1Hz)

Digital Control System
AnalogOpticalLeverPE:
Z 3Hz-P 300Hz

Digital
Anti-PE:
P 3Hz-Z 300Hz

Analog
Servo Filter
Target UGF 2-3Hz

Anti-DE:Z 3Hz-P 300Hz

αADC

DE:
P 3Hz-Z 300Hz

DAC

Gain
Fader

1−α
Wave
Front
SensorLabView (fs=1kHz)PE:
Z 3Hz-P 300Hz

PoundDrever
HallSignal

Servo Filter
Target UGF 800Hz

DSP (fs=200kHz)

MatrixCircuit

CoilDriverSensitivityl Sensitivity improvement achieved

So far, improvement below 150Hz was confirmed
TAMA300 Displacement Sensitivity

1010floor level@1kHz

dL- (2003/11/04) Old suspension system
dL- (2008/10/10) SAS-11-12

displacement
dL=4x10-19[m/rtHz]

Displacement noise [m/Hz1/2]

10(2008/10/10)

-10

10
10
10
10
1010
10-13-14strainh=1.3x10-21[/rtHz]-15-16-17-18-1910

1

2

3

45

6 7 8 9

102

2

3

4

56 7 8 9

10Frequency [Hz]323456 7 8 9104

Noise budget
l Estimated contributions of the various noise sources
TAMA300 noise budget(2008/10/10)-1310dL- sensitivity
Intensity noise
Alignment noisedl- feedback noisedl+ feedback noise
Shot noise
Detector noise
Det+ShotFrequency noise (err)
Upconversion noise

-14

1/2

Displacement noise [m/Hz ]

10-15

10-16

10-17

10-18

10-19

10-20

102

310

10
Frequency [Hz]