Current effortson the TAMA300 detector
National Astronomical Observatory of Japan
Koji Araion behalf of the TAMA collaboration
Amaldi6 meeting
2005/6/22
OkinawaTAMA300: Interferometer GW detectorl TAMA300:
A 300-m Power-recycled Fabry-Perot Michelson Interferometer
Site: National Astronomical Observatory of Japan(Mitaka, Tokyo)

l Operation of TAMA300
Fabry-Perot Michelson:
1999~2001
Power Recycling:
2001~Presentl This talk- Brief introductionof the control schemes and the loock acquisition- Current effort to improve the sensitivity,
being focused on the low frequency region (DC-200Hz)
and the mid frequency region (200Hz-2kHz)

Optical configuration of TAMA300

300m
FP cavity
Injection-locked
Nd:YAG Laser
P=8W

10-m
mode cleaner
F~1700fc=4.4kHz

300m
FP cavity

P=2W

RRM=0.5

F~500
fc=500Hz

RFPMI=0.9

Optical configuration of TAMA300

300m
FP cavity
Injection-locked
Nd:YAG Laser
P=8W

10-m
mode cleaner
F~1700fc=4.4kHz

F~500
fc=500Hz300m
FP cavity

P=2W

RRM=0.5

RFPMI=0.9
o Intentionally low RRM

G=4.6

o Shorter arm=> higher finesse=> lower reflectanceLength sensing and control
l Recycled Fabry-Perot Michelson Interferometer4 longitudinal d.o.f. to be controlled~ The optical cavities and the Michelson interferometermust be on the operating point

L−= L2−L1
L+= L2+L1
l− = l2 − l1
l+ = l2 + l1

L2
l2
l1

L1

Length sensing and control ~ for lock acquisitionl Based on the PDH technique and Schunupp modulation- single phase modulation at 15MHz- 3rd harmonic demodulation
at the reflection port
- PDH technique at the pick off ports
δ L2Phase Modulators
15.235 11.97
MHz MHzδ l+ Bδ l− B

Pickoff
SignalsN!

N!

3rd45.705
MHz harmonic
demod.

δ L1

Length sensing and control ~ for lock acquisitionl Based on the PDH technique and Schunupp modulation- single phase modulation at 15MHz- 3rd harmonic demodulation
at the reflection port
- PDH technique at the pick off ports
δ L2
Phase Modulators
15.235 11.97
MHz MHzδ l+ Bδ l− B

Pickoff
SignalsN!

N!

3rd45.705
MHz harmonic
demod.

δ L1

Length sensing and control ~ for lock acquisitionl Based on the PDH technique and Schunupp modulation- single phase modulation at 15MHz- 3rd harmonic demodulation
at the reflection port
- PDH technique at the pick off ports
δ L2
Phase Modulators
15.235 11.97
MHz MHzδ l+ Bδ l− B

Pickoff
SignalsN!

N!

3rd45.705
MHz harmonicdemod.

δ L1

Length sensing and control ~ for lock acquisitionl Based on the PDH technique and Schunupp modulation- single phase modulation at 15MHz- 3rd harmonic demodulation
at the reflection port
- PDH technique at the pick off ports
δ L2
Phase Modulators
15.235 11.97
MHz MHzδ l+ Bδ l− B

Pickoff
SignalsN!

N!

3rd45.705
MHz harmonicdemod.

δ L1

Lock acquisitionl Typically the lock is acquired within minutes~ need good pre-alignment
5Power recycling gain

43--- Inline arm--- Perpend. arm

Full lock

RecycledMichelson
One arm
locked210
102030Time [Second]4050

Alignment sensing and controll Wave front sensing technique- mode cleaner cavity- arm cavities- recycling mirror
QPDs
Gouy phasetelescopes

15.235 11.97
MHz MHz

QPDs

QPDs

Gouy
phase
telescopes

Lock acquisitionl Alignment control
for the arm, UGF: 5~10Hz, for the RM, UGF: ~10mHz5Power recycling gain

4--- Inline arm--- Perpend. arm
Alignment
Control ON

3210
10

2030
Time [Second]4050

Length sensing and control ~ for low noise model Common/differential separated control
Dark port=> Arm differential
Reflection port=> Arm common=> Michelson

Bright port 3f=> Recycling Mirror

Phase Modulators
15.235 11.97
MHz MHz6W

δ l+ BδL+δ l−N!

δL−

Sensitivity history
1010

Strain sensitivity [1/Hz1/2]

10No apparent improvement
since 2003/11~ (S3)

-14

Feb. 14, 1999
Sep. 3, 1999
Oct. 15, 1999
Mar. 16, 2000
Sep 4, 2000
Jun. 2, 2001
Jul. 12, 2003
Nov. 04, 2003
May. 27, 2005

-15-16

10-17

10-18

10-19

10-20

10-21

Last year:
Worked withRecycled Michelson
Restorationof the full interferometer:from 2004 autumn
Approached to the previous
sensitivity levelin the end of March

5 6 782102345 6 7 8310Frequency [Hz]234

5 6 7 8104

Noise budget
Displacement noise level of TAMA300

-6

10-7

dL- displacement
Laser frequency noise
Laser intensity noise
Detection+Shot noise
Shot noise
Detection noisemirror 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

1010-10

10-1110-12

10-1310-14

10-15

10-1610-17

10-18

10-19

10-20

10

0

10

1

10

2

10

3Frequency [Hz]

104

10

5

Current understanding about TAMA sensitivityl Low frequency
Seismic noise (DC~20Hz)
Noise from alignment servos (20Hz~200Hz)

l Middle frequency
Not known well (200Hz~2kHz)
Scattering noiseElectronics noisel High frequency noise~ shot noise (2kHz~50kHz)

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
Stabilize of the IFO
To ease lock acquisition

SAS: Seismic Attenuation Systeml Development of SAS
Collaboration with
Caltech and Universita di Pisa

l Installation

Filter Zero
VerticalPre-Isolator

StandardFilter
Monolithic
GAS

05 summer:
1 SAS for one of the end mass
05 autumn/winter:
The other 3 SASs

MiniGASl TargetMirrorTo improve seismic-related noise
direct or indirect noise couplings
Stabilize of the IFO
To ease lock acquisition

Passive Damper
Recoil Mass

Inverted
Pendulum

MirrorSuspension

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-IsolatorStandardFilter
Monolithic
GAS
MiniGASPassive Damper
Recoil MassMirror

Inverted
Pendulum

MirrorSuspension

1/2

Displacement noise [m/Hz ]SAS: Seismic Attenuation System10-4

10-5

Test@3mFP

10-6Displacement

10-7

10-8

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

10-11 m/Hz1/2

10-10

10-11RMS 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

10

Electronics
noise-14

10-15

10-2

10-1

10010
Frequency [Hz]101102

Expected: lower seismic/alignment noise,easier lock acquisition

Noise between 100Hz and 1000Hzl Limiting noise source ~ not knownl Scattered light noiseMichelson part of TAMA300: complicated
Pick-off mirrors
Internal reflections of 45o optics
Optical window
Multiple photodetectors

Noise between 100Hz and 1000Hzl Limiting noise source ~ not knownl Scattered light noiseMichelson part of TAMA300: complicated
Pick-off mirrors
Internal reflections of 45o optics
Optical window
Multiple photodetectors

Investigate noise levelof the Michelson partwith the simplest configuration as possible

Scattered light noisel Beam dump with ND filters
Combining commercial ND filters in a diamond shape~ not blewster angle reflection
but larger apperture(40mm with 2inch ND)~ vacuum compatible< 71ppm< 45ppm<420ppm< 600ppm

Recycled Michelson experiment-10

10

2004/1/15 Just after DT9
2004/1/29 PO removal, Dark WFS
2004/2/05 4PD->1PD, servo filter noise improv.
2004/2/12 PD modified
2004/2/28 Scattered light at the dark port
2004/4/23 Scattered light in the vacuum chamber

-11

1/2

Displacement noise [m/Hz ]

10-12

10-13

10-14

10-15

10-1610-1710110102

10

3

10410

5Frequency [Hz]Displacement noise: improved with the simplified RMI

1/2

Displacement noise [m/Hz ]Recycled Michelson experiment10-710-8

10-9

10-10

10-11

10-12

10-13

10-14

10-15

10-16

10-17

2004/11/11 without PO
2004/11/30 with PO

100

10

1

10

2

Reinstall the pick-offs

10

3

10

4

510 Frequency [Hz]- Stray beams cared by the ND beam dumps

The noise level was kept at the best

PD vacuum chamber at the dark portl To suppress the vibration of scattering objectsAvoid acoustic exicitation
Remove an effect of dusts
Vibration isolation by the stack
Separated from the main vacuum
Plan to put PDs in vacuum

RMBSPD

FrontMirror

11. PD chamber
Currently using small vacuum
chamberCurrently using small vacuum
chamber (Rough Vacuum)Electronic noisel dL- servo chain

Attenuator(de-emphasis)

Servo Filter(emphasis)

PD

Long Cable (~20m)

Demodulator

Matrix Coil Driver

1/2

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

102005/06/03
Matrix noiseElectronic noise couplingafter the servo filter-16

10-1710-1810-19102234567891032

Electronic noise /noise couplingvery close(but not dominating)=> need to put
frequency responce tothe coil driver=> Consider lock issue

Frequency [Hz]Summaryl Interferometric GW detector TAMA300
l Efforts focused on noise huntingl Low frequency (DC-200Hz)
Seismic noise (DC~20Hz)
Noise from alignment servos (20Hz~200Hz)
SAS is going to provide the improvement
Installation shortlyl Middle frequency (200-2kHz)
Essentially unknown
Scattering noises investigated with RMI
learned how to deal with them / PDs in vacuum

Electronics noise
redesignation of the gain distribution