Transcript Der Gravitationswellendetektor GEO600

Status of GEO600
Benno Willke
for the GEO600 team
ESF Exploratory Workshop
Perugia, September 2005
ESF 05 / GEO, B. Willke
container cluster 2005
Workshop
Central Building
Offices
Control Room /
Visitor Center
Bathrooms
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Tube / Trench
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Clean Room / Control Room
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Triple Pendulum Suspension
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Thermal Noise / Monolithic Suspension
Weld
Silicate
(HydroxyCatalysis)
Bonding
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reaction pendulum
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GEO 600 – optical layout
interferometer with
„dual recycling“
modecleaner
12W Laser
detektor
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Dual Recycling Length Control
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Michelson length control
< 0.1Hz
< 10 Hz
> 10 Hz
Reaction Pendulum:
3 coil-magnet actuators at
intermediate mass, range ~ 100µm
Electrostatic actuation on test mass
bias 630V, range 0-900V= 3.5µm
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Alignment Control
4 degrees of freedom
at MC 1
+4 at MC 2
+4 at MI (common mode)
+2 at MI (differential mode)
+2 at Signal-Recycling cavity
Alignment Control
16
+ 20 = 36
differential wave-front sensing
spot position control
ESF 05 / GEO, B. Willke
GEO 600 design sensitivity
ESF 05 / GEO, B. Willke
Evolution of the GEO 600 Sensitivity
h(t) [Hz-1/2]
Jan 02
10
-17
10
-18
10
-19
Aug 02 (S1)
Jan 04 (S3)
Aug 04
Feb 05 (S4)
10
-20
10
-21
Sept 05
10
2
Frequency [Hz]
10
3
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GEO600 Duty Cycle
date
run name
duty
cycle
longest
lock
Jan 2002
E7
75%
3h 40min
Aug 2002
S1
98%
121h
Nov 2003
Jan 2004
S3-I (7days)
S3-II(14 days)
95%
98%
95h
Aug 2004 –
Jan 2005
over night
runs
(51 days)
94%
Mar 2005
S4
97%
52h
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S4
 Feb 22nd – March 23rd, 708 hours
 Two manned shifts/day (5-21 UTC), 1 „Expert-On-Duty“ 8-8UTC
 Fully automated overnight shifts; SMS alarms to ‚E-O-D‘




Locking status
DAQS (DCUs running, frame making, timing, calibration)
Temperatures
Vacuum
 Instrumental duty cycle 97.5%, 95% w/o noisy period, 72%>10h
 Longest lock 52h
ESF 05 / GEO, B. Willke
detector characterization
 Sensitivity
 Min/max spectrum of
h(t)
 15 BLRMS of h(t)
 Inspiral monitor
 Spectrogram of h(t)
 Calibration
 Data quality
 Chi2
 Calibration parameters
 Bursts (HACRmon)
 Time frequency
distribution
 SNR distribution
 Duration
 Bandwidth
 Lines (Linemon)
 Line cataloguing
 Harmonic identification
 Sideband identification
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Typical S4 Sensitivity
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Calibration
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On-line optical TF measurements
P and Q
CAL
actuator
optical
h
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Calibration
radiation
pressure
calibrator
?
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Photon Pressure Calibrator
Wavelength: 1035 nm @ 20°C
Max. power: 1.4 W, FWHM= 0.66nm
Good agreement with ESD calibration
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Optical Gain
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h [1/sqrt(Hz)]
Calibrated EP Quadrature Signals
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Combining hP(t) and hQ(t) – results
h [1/sqrt(Hz)]
Get the best of hP and hQ
plus a little extra!
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increase of power recycling factor
Michelson Interferometer
Mode Cleaners
1500W (typ.)
2000W (max) at
Beam Splitter
Laser
10W 5
W
1.6W
T=0.09%
Power Recycling Cavity:
~40mW
Mode matching >85%
Finesse
8300
Linewidth
30 Hz
Output Mode Cleaner
4/0.09%*1.6 = 7000
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Thermal lensing in BS
output mode pattern (PRMI)
Directly after relocking
f=20km
A few minutes after relocking
f= 8km
→ α≈0.3 +/- 0.05ppm/cm
ESF 05 / GEO, B. Willke
GEO 600 design sensitivity
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Tuning signal recycling to 300 Hz
 lock acquisition at 5kHz
 tuning needs to adjust
of 6 parameters (lookup table)
 improved input file for
simulations and how to
transfer results to
experiment
 achieved downtuning to
200Hz
 MI AA instability could
be fixed
ESF 05 / GEO, B. Willke
Interferometer Readout - Sidebands
mirror
laser
phase
modualtor
beam
splitter
mirror
photo
detector
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Schnupp – Modulation
mirror
laser
phase
modualtor
beam
splitter
mirror
photo
detector
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Gravitational Wave Side Bands
mirror
laser
phase
modualtor
beam
splitter
mirror
photo
detector
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Detuned Signal Recycling
mirror
laser
phase
modualtor
beam
splitter
mirror
photo
detector
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Unbalanced Sidebands
PRC
119*D (1.26kHz)
72*D (
72*D (
765Hz)
119* D (1.26kHz)
765Hz)
SRC
broadband
1.86kHz
2.2kHz
2.3kHz
1.1kHz
SRC
detuned to
1.1 kHz
-119 * f PRC
carrier
MI-sidebands
-72 * f PRC
SR-sidebands
broadband
0
SR-sidebands
1.1kHz detuned
72 * f PRC
119 * f PRC
SR-sidebands
2kHz detuned
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Signal Recycling digital
 digital loop allows for
steep filter
 noise contribution reduced
by up to a factor of 200
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Sqrt circuits in MI loop
ESD: F  U^2
Sqrt circuits are
necessary to give
full linear force
range for
acquisition.
Drawback: sqrt
circuits are noisy
1µV/sqrt(Hz)
(=100µV/sqrt(Hz)
@ ESD)
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MI loop whitening / dewhitening
dewhiten
Whitening right
after mixer:
zero 3.5 Hz
pole 35 Hz
Dewhitening for
both split passes
dewhiten
Passive dewhitening done in HV
path (0-1kV)
dewhiten
Whiten
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sensitivity improvements since July
ESF 05 / GEO, B. Willke
Evolution of the GEO 600 Sensitivity
h(t) [Hz-1/2]
Jan 02
10
-17
10
-18
10
-19
Aug 02 (S1)
Jan 04 (S3)
Aug 04
Feb 05 (S4)
10
-20
10
-21
Sept 05
10
2
Frequency [Hz]
10
3
ESF 05 / GEO, B. Willke
Current vs. Design sensitivity
GEO600 Theoretical Noise Budget
-17
10
Seismic
Suspension TN
Substrate TN
Coating TN
Thermorefractive
Shot 350Hz
Total
Shot Sept 1
h(t) Sept 1
-18
10
-19
ASD [h/ Hz]
10
-20
10
-21
10
-22
10
-23
10
-24
10
2
10
Freq. [Hz]
10
3
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Non-stationary Noise
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Near Future
 finish commissioning

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increase circulating power
find source of optical losses in PR cavity
increase MI loop gain between 1-10 Hz
improve RF circuitry
optimize stability
 join S5 in overnight/weekend mode until
commissioning is finished
 fully join S5
ESF 05 / GEO, B. Willke
ESF 05 / GEO, B. Willke