Current status of the TAMA300 interferometer

Masaki Ando
Department of Physics, Faculty of Science, University of Tokyo.
S. NaganoB , K. AraiA , S. Taniguchi, Gerhard Heinzel A, R. TakahashiA ,S. KawamuraA , D. TatsumiB , S. TeladaA , A. OkutomiB , S. MoriwakiC , T. KandaE ,M. FukushimaA , T. YamazakiA , M. OhashiA , N. MioC , K. Kawabe, A. ArayaD , M. MushaF ,K. Tochikubo, N. Ohishi, K. Yamamoto, A. Takamori, A. Sekiya, K. Numata, S. Ohtsuka,A.UedaA , S. MiyokiB , S. SatoB , K.UedaF , M.-K. FujimotoA , K. Tsubono, K. KurodaB ,and TAMA collaborationF,GDepartment of Physics, University of Tokyo, NAOA, ICRRB ,Department of Advanced Materials Science, University of TokyoC , ERID ,Miyagi University of EducationE , UECF , KEKG

2nd TAMA Workshop (October 20, 1999, Tokyo, Japan)
1

Contents· Introduction.
× Overview
× Current status of TAMA300 interferometer.
· TAMA300 interferometer.
× Optical and control con guration.
× Performance of control system.
· Sensitivity of the TAMA300 interferometer.
× Sensitivity.
× Noise estimation.
· Stability of the TAMA300 interferometer.
× Long-term operation in Data Taking 2.
· Summary and future works.
2Introduction (1)Overview of the TAMA300 interferometer· Features of the TAMA300 interferometer× Sited at National Astronomical Observatory in Mitaka, Tokyo.
× Fabry-Perot-Michelson interferometer with arm length of 300m.
× Nd:YAG laser source with output power of 10 W.
× 10 m ring-type mode cleaner.
× Power recycling.
300 m
arm cavity(NS arm)

300 m arm cavity(WE arm)
EOM

12 MHzGravitational wave signal ( L-)Introduction (2)Development steps of the TAMA300 interferometer· First observation phase (Phase I).
Phase I× Operate almost the whole interferometer.
× 10 W laser source with 10 m mode cleaner.
× Main interferometer with 300 m arm cavities.
× Without power recycling.
× Data taking and analysis.
× Sensitivity

3

10 20 .

( obs = 300 Hz, ∆ obs = 300 Hz)
Displacement noise 5 10 19 m Hz.
Laser frequency noise 1 10 6 Hz Hz.

300m Fabry-Perot-Michelson interferometerwith 10W laser source and mode cleaner

h ~ 3 x 10-20
Phase II· Improve the sensitivity (Phase II).
× Implement power recycling.
× Sensitivity
3 10 21 .
( obs = 300 Hz, ∆ obs = 300 Hz)
Displacement noise 5 10 20 m Hz.

Power-recycled interferometerh ~ 3 x 10-214

Introduction (3)Current status· TAMA300 interferometer× Operated with the nal con guration for Phase I.
× Sensitivity
7 10 18 m Hz.
× Stability
Continuous operation over 7 hours.
× Improve sensitivity and stability.
× Characterization· Data taking
× Data taking 1 (August 06)
1 10 16 m Hz.
× Data taking 2 (September 17 - 20)
1 10 17 m
Data analysis.
5Hz.

Introduction (4)Current sensitivity of TAMA300· Sensitivity

710 18 m

10 20 1Hz ( 2Hz)

–1210–1010–14

10–1210–1610–1410–18

10–16

10–2010–18

10–2210–20

10101210310104510TAMA300 interferometer (1)TAMA300 interferometer for Phase I· High-power and stable laser source (10W laser and 10m MC).
· Main interferometer (300m Fabry-Perot-Michelson interferometer).
EM2

300 marm cavity(NS arm)

Fabry-Perot-Michelson interferometerwith an arm length of 300 mFM2

Injection-locked
10 W laser

10 m Mode cleaner

Fiber LDRMYAG300 m arm cavity(WE arm)

PO2BS

FM1

FI
EOM

EOM

VCM

IMLD pumped
10 W laser

10 mringcavity

15.235 MHz
20 MHz

NPRO
700 mW
EOM

PO1OM

EOMPD

12 MHzMixer

EM

Gravitational wave signal ( L-)

7EM1

TAMA300 interferometer (2)Laser source· Injection-locked Nd:YAG laser.
Injection-locked
10 W laser

× Output power of 10 W.
× Master laser

10 m Mode cleaner

20 MHz× LD-pumped Nd:YAG laser (700 mW).

Injection locking
control× Slave laser
× Fiber LD-pumped ring laser.

QPD

PD

Fiber LDMC alignment
control

Mixer
MixerYAG× Injection-locked to the master laser.

EOM

EOM· 10-m ring cavity.

VCM

IMLD pumped
10 W laser

× Three mirrors — Independently suspended.

15.235 MHz× Finesse — 1,700.

10 mringcavity

PD

20 MHz

NPRO
700 mW

OM

Mixer
Mixer
EOM

EOM

12 MHz× Transmissivity — 54%.
× Transmission of modulation sidebands.

EM· Frequency control.

SUM

× MC end mirror (Laser frequencystabilization

1kHz).

× Feed around (1 kHz 20 kHz)

30 kHzMC mass loop
SUM

Feed around loop

· Intensity stabilization.
8Common motioncontrol L+)

TAMA300 interferometer (3)Main interferometer with the 300-m arm cavities· Michelson interferometer with
300-m Fabry-Perot arm cavities.

Fabry-Perot-Michelson interferometerwith an arm length of 300 m

× Finesse — 516.

EM2

× Cut-oﬀ frequency — 480 Hz.
300 marm cavity(NS arm)· Controlled withthe frontal modulation scheme.
×signalfront mirrors (diﬀ.).

×signalbeam splitter.

×+ signal

Mirroralignment
controlBS
orientation
control

Ly
Differential motion
control L-)

FM2
Mixer
QPD
Mixer

PO2laser and MC.

300 m arm cavity(WE arm)

PDBS· Alignment control system.

FIFM1
PO1× Wave-front sensing scheme.
× Sample small power with pick-oﬀ mirrors.

PD· Low-freq. drift control system.

Interferencefringecontrol l-)

Mixer

× BS orientation control.
×

Thermalcontrol

Mixer

Mirror alignment
control
QPD

Mixer

PDPD

Mixer

Lx

Gravitational wave signal ( L-)thermal control.

Common motioncontrolL+)

9EM1

TAMA300 interferometer (4)Main control loops· Operational point of the interferometer.
× Two arm cavities — Resonate with input laser beam.
× Interference fringe — Dark at the detection port.

· Three d.o.f. to be controlled.
× Arm cavity diﬀerential motion (1010)

Front Mirror coil-magnet actuators (diﬀerential).

× Arm cavity common motion (+)× Michelson fringe motion (BS coil-magnet actuator.

)

Laser source (MC and feed around).

2010–2

10–4

10–6

10

1210103410104102

10010

1102

103104

102

100

10–2

10–4

10100

100

100

000–100–100–100

101210103410101102103104

100101102103010

1102

103TAMA300 interferometer (5)Alignment control loops· Alignment control of the interferometer.
stable operation and high sensitivity.
· 8 d.o.f are controlled for the main interferometer.
× Signals are extracted from picked-oﬀ beams.
× Use the WFS scheme for each arm cavity.
× Feed back to coil-magnet actuators of each mirror.
10 Hz.

Abs.

10102

WE front pitch

WE front yaw

0100Abs.

UGF

–2

10–2

10–4

100

1102103101000–100010121010
Frequency [Hz]0101102

1001010Frequency [Hz]121010Phase [deg]10Phase [deg]×3101000–100
101133TAMA300 interferometer (6)Performance of alignment control loops· Without alignment control
× Large pitch motion

IFO goes out of lock in several minutes at best.

· With alignment control
× Well-aligned automatically.
× Stable operation over 7 hours.
Transmitted light power [V]7654yaw cantrol on

32pitch control on

10010203040Time [sec.]
125060TAMA300 interferometer (7)Low-frequency drift control loops· BS orientation control.
× Sensitivity is degraded by BS orientation drift.
(Arm cavity transmissivity, Contrast.)

BSNS arm× BS orientation is controlled with QPD at the end room.

Alignmentcontrol

QPD
Alignmentcontrol

× Detect beam position of transmitted beam.
× Fed back to BS(coil-magnet actuator, PZT at suspension point).
×·UGF

0.3 Hz.

Tilt

WE end mirror

thermal control.
× Finite dynamic range forSuspension

actuator (Mirror

50 m ).

Stack×is dragged by.
L- feedback
signal× Cancelfeedback signal by the tilt of the isolation system.

× Heater is attached at the bottom of WE-end VIS.
×UGF

3 mHz.
Heater

13Displacement

TAMA300 interferometer (8)BS orientation control loops

10–3

10–4

10–5

Feedback sig.

10–2

1/2

Fluctuation [V/Hz ]· BS orientation uctuation is suppressed by the control loop.

NS trans. pow.

Without control

With control

Pitch

–6

10

100Contrast

10–1

10–2

–3

Without control

10–4

With control

10Yaw–5

10

Without control

With control

4
3.9
3.8
3.7
3.6
3.5
0.96
0.95
0.94
0.93
0.92

Alignment FB.

1/2

Fluctuation [V/Hz ]

10 –2
100–2

–1

10
Frequency [Hz]

100

0.8
0–0.80510Time [min.]1415

Sensitivity of the TAMA300 interferometer (1)Displacement noise level· Displacement noise level
7 10 18 m Hz. (700 900 Hz).
14 times worse than the goal sensitivity for Phase I.
1/2

Displacement noise [m/Hz ]–8

10

October 15, 1999

–10

10–12

10

–14

10–16

10oal

Ig
hase

–18

P

10P

–20

10oal

II g
hase

010

1

102

3

10
10
Frequency [Hz]15410105

Sensitivity of the TAMA300 interferometer (2)Noise estimation· At the observation band ( obs = 300 Hz, ∆ obs = 300 Hz),
Alignment control noise is dominant.
× Sensitivity is degraded coupling with× Asymmetry in actuator eﬃciencies.
× Beam miss-centering on mirrors.
Beammiss-centering

× New alignment control lters.

Actuator
asymmetry× Beam-centering ad ustment.
× Improvement of WFS noise level.

16

Displacement noiseSensitivity of the TAMA300 interferometer (3)Alignment control noise· Sensitivity will be improved
with new alignment control lters.

1/2

Displacement noise [m/Hz ](with steep LPF with 10-pole Chebyshev low-pass ﬁlter.)

10–8

10–10

10–12

10–14

10–1610–1810–20

Alignment control noise (improved filter)
Alignment control noise
L– displacement noise

01010

123

1010Frequency [Hz]17104105Sensitivity of the TAMA300 interferometer (4)Noise sources· Contribution of several noise sources are estimated.
× Noise sources to be considered.
× Shot noise, Thermal noise, Seismic noise, Laser frequency noise,Laser intensity noise,control noise, Detector noise, AC line noise, ....

10–8

–10

10–12

10–14

10–16

10–18

10–20

1010

0

110210310410510

Stability of TAMA300 interferometer (1)Long term operation· Data taking 2 (September 17· Total operation time20).

about 31 hours.

10.5

010.5
WE arm cavity
NS arm cavity
010.95September 18

September 19
Date / Time19

September 20

06:00

03:00

00:00

21:00

08:00

06:00

03:00

00:00

21:00

06:00

03:00

0.85

00:00

0.9

21:00

Contrast

Arm trams. pow.

MC trans. pow.

(September 17–20, 1999)

Stability of TAMA300 interferometer (2)Stability· The interferometer is kept lock stably.
× Total operation timeabout 31 hours in 3 nights.

× Longest locking timeabout 7 hours 43 min..

· Power uctuation.
× Arm cavity transmissivity
× Contrast

uctuation less than 2 .

uctuation between 9- 97 .

× Arm cavity alignment control.
× BS orientation control.

× Mode cleaner

uctuation about 10

× No alignment control at this time.

· Sensitivity in long term operation
× Burst-like noise appeared occasionally.
20

Summary and future works· The main interferometer isoperated with the nal con guration for Phase I.
× Sensitivity

710 18 m

Hz.

× The interferometer was operated over 7 hours continuously.
· Improve the sensitivity

10 19 m× Reduce alignment control system noise.
× Reduce detection system noise and the other noises.

· Characterization.
· ealize stable operation.
· Improve stability of sensitivity.

21Hz.

Sensitivity of the TAMA300 interferometer
Alignment control noise

1/2

× Sensitivity is degraded coupling withDisplacement noise [m/Hz ]· Alignment control noise.
× WFS noise.
× Asymmetry in actuator eﬃciencies.
× Beam miss-centering on mirrors.

× New alignment control lters.
× Beam-centering ad ustment.
× Improvement of WFS noise level.

10–8Withalignment control–1010–1210–1410

Withoutalignment control–1610

–18

100

10

1

10

Frequency [Hz]222

10310