Current Status of Japanese Detectors

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Current Status ofJapanese Detectors

• Daisuke Tatsumi
• National Astronomical Observatory of Japan

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Contents

• The Japanese Detectors
• TAMA
• CLIO
• DECIGO
• Analysis (Brief introduction)
• Inspiral (Tagoshi)
• Veto analysis (Ishidoshiro)
• Noise characterization (Akutsu)

This is a content of my talk. First, I would like
to talk about the current status of TAMA, CLIO
and DECIGO detectors. And then I will give a
brief introduction to the current activities of
data analysis.
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The Japanese Detectors

• Two prototype detectors for LCGT are being
  developed in Japan.
• TAMA
• Location Suburb of Tokyo, Japan
• Baseline length 300m
• CLIO
• Location Kamioka underground site, Japan
• Baseline length 100m
• Feature Cryogenic Sapphire Mirrors

One is TAMA detector which is located in west
suburb of Tokyo. It has a baseline length of
three hundred meters. The another is CLIO
detector which is located in Kamioka mine. This
mine is about three hundred kilo-meters away from
Tokyo. The most important feature of this
detector is that it adopts cryogenic sapphire
mirrors.
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TAMA

• Brief History
• 1995 Construction start
• 1999 First observation experiment
• 2000 World best sensitivity
• at the time
• 2001 1000 hours Observation
• 2002 Power recycling (PR)
• 2003 Second 1000 hours observation with PR
• 2004 The ninth observation experiment

TAMA has started observation experiments since
1999. By the beginning of 2004, 3000 hours of
data in total was accumulated through the nine
observation experiments.
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TAMA upgrade

• After the last observation experiment in 2004,
• TAMA detector is being upgraded to reduce the low
  frequency noises.

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TAMA SAS (Seismic Attenuation System)
TAMA-SAS (IP GASF Payload)
To reduce the seismic noise, new isolation system
is being installed. This figure shows a
schematic view of TAMA SAS. To isolate horizontal
motion, an inverted pendulum is implemented. For
vertical motion, double stage MGAS filters are
used. Finally mirror was suspended by a double
pendulum.
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SAS Installation Schedule

• 2005
• Sep First SAS was installed for inline end
  mirror (1)

2006 Jun Second SAS was installed for inline
near mirror (2) Aug A Fabry-Perot cavity was
locked with SAS,
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Oct Third and forth SAS were installed to the
perpendicular arm cavity (3), (4).
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1
2
The SAS installation was started in September,
2005. In this summer, a Fabry-Perot cavity was
locked with SAS. Now all of four test mass
mirrors are suspended by SAS.
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Stable lock of SAS Fabry-Perot cavity
With the locked Fabry-Perot configuration, we
operated the interferometer. In this
configuration, one arm was installed SASs but
another one was still old suspensions. The
cavities were locked for six and a half
hours. Even if in the daytime of the working
days, stable locks were realized by SAS. This is
a important progress for TAMA, because many human
activities disturbed our observations.
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Improvement of cavity length fluctuation

• This figure shows the improvement of a cavity
  length fluctuation by using SAS.
• Above 2 Hz region, the SAS improved the seismic
  noise more than 24 dB.

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Improvement of angular fluctuations

• The angular fluctuation of the mirror is also
  reduced by SAS.
• Above 3 Hz region, the SAS improved the angular
  fluctuations more than 25 dB.

Actual improvements at 100 Hz region will be
confirmed by locked Fabry-Perot
configuration. And then, our detector will be
tuned for power-recycled Fabry-Perot Michelson
configuration by the end of next July.
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TAMA Summary

• - To improve low frequency sensitivity, we are
  installing SAS for the test masses.
• - We confirmed
• Stable mass lock of a cavity with SAS,
• Improvement of length fluctuation and
• Improvement of angular fluctuations.
• We are currently tuning SASs for another cavity.
• We plan to take data in the next summer
• and plan to continue TAMA operations with
• RD for LCGT.

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CLIOCryogenic Laser Interferometer
Observatoryin Kamioka mine
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CLIO LCGT

• Purpose of CLIO (100m arm length)
• Technical demonstration of key features
• of LCGT.
• LCGT is a future plan of Japanese GW group.
• LCGT
• is located at Kamioka underground site
• for low seismic noise level,
• adopts Cryogenic Sapphire mirrors
• for low thermal noise level and
• has arms of 3km long.

Except for the arm length, CLIO has same features
of LCGT. Therefore, the detector can demonstrate
them as a prototype of LCGT.
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Construction
All of vacuum pipes, cryostats and cryocoolers
were installed by the June, 2005.
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First operation of the cryogenic interferometer

• First operation of the cryogenic interferometer
• has been demonstrated on 18 February, 2006 !

23K
End Mirror
Temperature (K)
Lock
about 50 min.
Near Mirror
20K
This figure shows mirror temperatures as a
function of time. During the lock, the mirrors
keep its temperature around 20K.
20K
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CLIO sensitivity at 300K
After the several cryogenic operations, CLIO
detector has been operated at 300K. To improve
the sensitivity, noise hunting is in progress.
This figure shows the current best noise spectrum
of CLIO. At all of frequency regions, the
differences from the target sensitivity at 300K
are about a factor of 4.
Displacement (m/rtHz)
10
100
1k
10k
Frequency (Hz)
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Observable ranges forInspiral GW signals
1.4Msolar

• For neutron star binaries, CLIO and TAMA can
  observe the event within 49kpc and 73kpc,
  respectively.

CLIO
TAMA
LISM
We can say that the two detectors have almost
same sensitivity.
At over 10 solar mass region, CLIO keeps good
sensitivities due to its low seismic noises. It
is the greatest benefit of underground site.
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CLIO Summary

• The first operation of the cryogenic
  interferometer was successfully demonstrated.
• Current sensitivity at 300K is close to the
  target sensitivity within a factor of 4.
• Several observation experiments at 300K are in
  progress.
• (Details of detector characterization will be
  given
• by Akutsu)
• - Once the displacement noise reaches at thermal
  noise level, its improvement by cooling will be
  demonstrated.

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DECIGO DECi-hertz Interferometer Gravitational
Wave Observatory
The DECIGO project is also in progress. The
pre-conceptual design has been finished. Most
important feature of this detector is adopting
the Fabry-Perot Michelson scheme. Its baseline
length is 1000 km. Each of cavities has a finesse
of 10. By using this detector, GW signals of
deci-hertz region will be detected.
Pre-conceptual Design FP Michelson
interferometer Arm length 1000 km Orbit and
constellation TBD Laser 532 nm, 10 W Mirror
?1 m, 100 kg Finesse 10

• NSNS (1.41.4Msun)
• zlt1 (SNgt26 7200/yr)
• zlt3 (SNgt12 32000/yr)
• zlt5 (SNgt9 47000/yr)
• IMBH (100100Msun)
• zlt1 (SNgt1000 ?/yr)

Drag-free satellite
BHBH(1000Msun) _at_z1
merger
Arm cavity
Foreground
?GW 2.2?10-16
3 year-correlation
NSNS_at_z1
PD
Laser
Arm cavity
merger
PD
Drag-free satellite
Drag-free satellite
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Activities of Data Analysis

• Detector Characterization
• Veto analysis by Ishidoshiro
• CLIO data by Akutsu
• Inspiral
• A combined result of DT6, 8 and 9 for galactic
  events was obtained by Tagoshi

Finally I would like to give a brief introduction
to the activities of data analysis. In this
afternoon session of detector characterization,
two talks will be given. One is veto analysis of
TAMA data by Ishidoshiro. The other is the
evaluation of the first CLIO data by Akutsu.
The last topic is the inspiral search of TAMA
data by Tagoshi.
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TAMA inspiral analysis
by H. Tagoshi, et al.
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TAMA inspiral analysis (1)
Search for inspiraling compact binaries were
performed by using TAMA data in 2000-2004.
Period Data length hours Analyzed data hours
DT4 Sept. 00 154.9 147.1
DT5 Mar. 01 107.8 95.26
DT6 Aug.-Sept. 01 1049 876.6
DT8 Feb.-Apr. 03 1163 1100
DT9 Nov.03-Jan.04 556.9 486.1
2705
2462.8
Total length of data analyzed (DT 4,5,6,8,9)
Length of data for upper limit (DT 6,8,9)
We derived a single (combined) upper limit from
DT6, 8, and 9 data. This enable us to derive a
more stringent upper limit than previous works.
(DT4 and 5 data were not used for upper limit,
since they were shorter and sensitivity was much
inferior than later DT6-9 data).
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TAMA inspiral analysis (2)
Upper limit on the Galactic event rate
Data length hours Detection probability of Galactic signals Threshold of ? (false alarm rate 1 /yr) Upper limit to the Milky Way Galaxy events events /yr (C.L.90)
DT6 876.6 0.18 21.8 130
DT8 1100 0.60 13.7 30
DT9 486.1 0.69 17.7 60
Single upper limit is given by
by using data of 102.6 days
Conservative upper limit
(gr-qc/0610064, PRD in press)
By using data of a hundred days, we set a
combined upper limit to be 20 events per year on
galactic events. This result was accepted by PRD.
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End