Transcript GEO Comissioning Status - ego

Title
GEO 600
Commissioning Status
Based on a talk of Stefan Hild for the WG1 meeting in Perugia
Max-Planck-Institut für Gravitationsphysik
(Albert-Einstein-Institut)
Harald
Lück
for
the GEO600
team
Harald Lück
for the
GEO600
ComissioningComissioning
team
1
ILIAS meeting
Palma,
Oct.
2005
ILIAS Meeting,
Palma,
Oct. 2005
GEO 600 layout
0.09
1.5-2 kW
Harald Lück for the GEO600 Comissioning team
2
ILIAS Meeting, Palma, Oct. 2005
Tuning signal recycling to 300 Hz
Better knowledge of IFO
parameters:
more accurate parameter
predictions from simulations
downtuning to 200 Hz
realized
Fixed instability of MI autoalignment by setting up a new
telescope for DWS.
We will stay at 330 Hz !
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
GEO 600 design sensitivity
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
RF setup
Old setup:
• Dominated by phase
noise in the LO path
(phaseshifter and
splitter(0/90°)
• Due to this noise
Q was mixed into P
quadrature.
OLD setup
NEW setup
New setup:
• Using a less noisy
splitter(0/90°)
• Using a cable as
phaseshifter
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Shot noise
Green line is the shot noise level calculated from the DC current of the photodiode.
We are within a factor sqrt(2) shot noise limited above 1kHz !
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Next step in RF setup (next week)
Proposed by Rana and others
GOALS:
• Using only high quality hardware
• Guaranteeing high RF levels in all components
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Noise projections 21st of july
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Noise in the SR-long loop
PROBLEM
Noise in the detection band is entirely limited by front-endnoise (shot noise from the detector).
Limits sensitivity from 100 to 500 Hz
Requirements
• Large locking range
• OLG of 10^6 at 0.1 Hz
• No feedback noise above100 Hz
Solution
1. Servo has a locking mode and a running mode
2. Lowering UGF to get less gain in detection band
3. Using lowpass filter with very steep roll off above UGF
(implemeted digitally using a dSPACE system)
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Analog SR electronics
Red = acq amp, green = acq pha
Dark blue = run amp, brown = run phase
Light blue = run2 amp, pink = run2 pha
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Signal Recycling digital
Phase @18 Hz = -147 deg
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
SR feedback: analog vs. digital
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Sensitivity improvement July to August
High frequency improvements: reduction of RF phase noise
Low frequency improvements: reduction of Signal recycling feedback noise
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
PR-bench
Historically grown
layout of PR-bench
not optimal !
• beam clipping
• too many
transmissive optical
components
• too many polarizing
components
• acoustic coupling
Goal:
Shorten and simplify
the HPD path
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Sensitivity after PR bench work
Removed resonance structures between 100 and 200 Hz.
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Noise projections 4th of August
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Michelson length control
< 0.1Hz
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Michelson length control
< 0.1Hz
< 10 Hz
Reaction Pendulum:
3 coil-magnet actuators at
intermediate mass, range ~ 100µm
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
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
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Using ESD as actuator
• Force is proportional to
square of applied voltage.
• high voltages are needed
• for bipolar actuation a bias
voltage needs to be applied
Noise is introduced:
• loop electronics
• sqrt circuits
• intrinsic HV amplifier noise
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
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)
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
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)
Bypassing sqrt
circuits after lock
is acquired.
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Noise in MI loop
HVA noise =
100nV/sqrt(Hz)
(=10µV/sqrt(Hz)
@ ESD)
HV-amplifier noise
can be reduced by
decreasing bias
voltage or active
noise suppression.
Suppressing noise
introduced by loop
electronics needs
whitening
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
MI loop whitening / dewhitening
Whitening right
after mixer:
zero 3.5 Hz
pole 35 Hz
dewhiten
Dewhitening for
both split passes
dewhiten
Passive dewhitening done in HV
path (0-1kV)
dewhiten
Whiten
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Sensitivity after fixing noise from MI loop
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Noise Projections 6th of October: Excess noise @ 200Hz
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Current sensitivity 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
Harald Lück for the GEO600 Comissioning team
Freq. [Hz]
27
10
3
ILIAS Meeting, Palma, Oct. 2005
Laser Improvements
• Exchanged master laser and slave laser pump
diodes for new ones (13.3W from Laser)
• Improved optical path
• Cleaned components on laser bench
→ max. 9.2 W @ MC1
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Burst events; Start-of-the-second glitches
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Start-of-the-second glitches: A cal. issue
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
New MI longitudinal loop:
reduce longitudinal dark fringe deviations
Old
Overall gain
New
Much more
gain @ low f
Harald Lück for the GEO600 Comissioning team
Overall gain
31
ILIAS Meeting, Palma, Oct. 2005
Low Frequency EP Reduction
10
nfft/fs = 10.00 : navs = 30 : enbw = 0.15 : nsecs = 300
0
G1:LSC_MID_EP-P_HP
fs = 16384 : 2005-09-26 09:08:28
10
Amplitude (Vrms / Hz 1/2)
10
10
10
10
10
-1
-2
-3
-4
Optional:
-5
Digital IM Feedback
-6
= analog + res. @ 2.5Hz
10
-7
-1
10
10
0
1
10
10
2
10
3
4
10
Frequency (Hz)
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
MI AA digital (dSpace) servo
14th Sept.
Digital
Analog
Added res.
gain stages
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
MI AA digital (dSpace) servo
8th Oct.
Digital filter TFs contain resonant gain
stages for suspension resonances
Rotation (Yaw)
Tilt (Pitch)
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Reducing Noise in MI AA Loop
19th Oct.
• Optimization of gain
distribution in MI AA loop
reduced FB noise
Feedback
Camera
darknoise
noise
Before
Before
After
After
Before
Before
After
After
Tilt (Pitch)
Rotation (Yaw)
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Stationarity / Gaussianity
Log(N)
Histograms of BLRMS
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Current work / next steps
• Non stationary noise (already partly? cured)
• Decrease low frequency EP deviations for most
loops, i.e. increase gain (partly done)
• Improve RF set-up
• Enhance to full input power
• Join S5. First in overnight/weekend mode
– When close to design sensitivity join in 24/7 mode
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005
Sensitivity improvement of GEO
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
Harald Lück for the GEO600 Comissioning team
Frequency [Hz]
38
10
3
ILIAS Meeting, Palma, Oct. 2005
Sunset in Ruthe
¿Preguntas?
Translation Alta Vista Babelfish 
Harald Lück for the GEO600 Comissioning team
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ILIAS Meeting, Palma, Oct. 2005