Transcript G030033-00 - DCC

40m Laboratory Upgrade
Progress Report
Osamu Miyakawa, Caltech
40m Technical Advisory Committee
LIGO-G030033-00-R
Primary objective: full engineering
prototype of optics control
scheme for a dual recycling
suspended mass IFO, as close
as possible to the Advanced
LIGO optical configuration and
control system
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Advanced LIGO technical
innovations tested at 40m
 a seventh mirror for signal recycling
» length control goes from 4x4 to 5x5 MIMO
 detuned signal cavity (carrier off resonance)
 pair of phase-modulated RF sidebands
» frequencies made as low and as high as is practically possible
» unbalanced: only one sideband in a pair is used
» double demodulation to produce error signals
 short output mode cleaner
» filter out all RF sidebands and higher-order transverse modes
 offset-locked arms
» controlled amount of arm-filtered carrier light exits asym. port of BS
 DC readout of the gravitational wave signal
Much effort to ensure high fidelity between 40m and Adv.LIGO!
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Differences between
AdvLIGO and 40m prototype
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Initially, LIGO-I single pendulum suspensions will be used
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Only commercial active seismic isolation
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AdvLIGO will have 6 cm beam spots, using less stable cavities
40m can move to less stable arm cavities if deemed useful
Arm cavity finesse at 40m chosen to be = to AdvLIGO
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Other facilities will test high-power laser (LASTI, Gingin)
Thermal compensation also tested elsewhere
Small (5 mm) beam spot at TM’s; stable arm cavities
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STACIS isolators in use on all test chambers, providing ~30 dB of isolation from 1-100 Hz
No room for anything like full AdvLIGO design – to be tested at LASTI
LIGO-I 10-watt laser, negligible thermal effects
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No room for full scale AdvLIGO multiple pendulums – to be tested at LASTI
Scaled-down versions to test controls hierarchy in 2004?
Storage time is x100 shorter
significant differences in lock acquisition dynamics, in predictable ways
Control RF sidebands are 33/166 MHz instead of 9/180 MHz
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»
Due to shorter PRC length
Less contrast between PRC and SRC signals
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Target sensitivity of
AdvLIGO and 40m prototype
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Milestones Achieved as of
Spring LSC Meeting
 The characterization of the mode cleaner performance, and its interaction with the prestabilized laser system, occupied much of fall 2002. By the end of December 2002, the
noise performance of the system met specifications.
 The intensity stabilization system (ISS) for the pre-stabilized laser continues to be
developed and installed.
 The Global Diagnostics System (GDS), including DTT, AWG, and DMT have been installed,
and DTT/AWG is in use.
 Five new temperature-controlled vacuum bake ovens were commissioned in the South
Annex of the laboratory, and many bake jobs were completed and qualified.
 8 of 10 digital suspension controllers for suspended optics were completed by the end of
calendar 2002. ETMｘ and ETMy remain to be completed.
 All 10 core optics were produced, polished, and coated, and their optical properties
measured by LIGO engineers, by August 2002.
 All of the mechanical suspensions for the core optics for the main dual recycled
interferometer were designed, fabricated, cleaned and baked.
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Milestones Achieved as of
Spring LSC Meeting
 Sensor/actuators (OSEMs) for the all the suspended optics were assembled, cleaned and
baked, tested, and prepared for installation.
Three core optics (Beamsplitter, ITMx, and ITMy) were suspended and damped in February
2003. Four remain to be suspended by the summer 2003.
Remaining optical sensing equipments of AP, SP & MC, ITMx, ITMy, TRx, TRy were
assembled and installed on the optical tables in February 2003.
Several key auxiliary systems (the in-vacuum Faraday isolator, the in-vacuum mode
matching telescope with off-axis parabolic mirrors, the in-vacuum PZT steering mirror system,
and the optical lever zoom telescope system) were designed, and components procured, by
the end of 2002. They are now being assembled.
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Lock stability of 13meter MC
MC transmitted power MC reflected power
Jan.10/2003 17PM – Jan.12/2003 8AM
39 hours lock with detection mode
 Digital controlled suspensions.
 Smooth Lock acquisition (within
5sec).
 Robust lock.
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Measured open loop T.F. of MC
12/23/2002
 Calculated gains obtained by
Rana’s model on Matlab agree
with measurements.
Open loop transfer function of Mode Cleaner
200
Calculated Mirror loop gain
Calculated VCO loop gain
Calculated total loop gain
Measured Mirror loop gain
Measured VCO loop gain
Measured total loop gain
Mag[dB]
150
100
 Unity gain frequency=67.2kHz
(design:over 100kHz)
 Phase margin=28.4deg
 Phase delay on total loop at high
frequency limits the unity gain
frequency.
C=10dB, B=16dB, L=30.4dB
Unity gain freq.=67.2kHz
Phase margin=28.4deg
Cross over freq.=26.6Hz
50
0
150
Phase[deg]
100
 Cross over frequency=26.6Hz
 Phase delay on Mirror loop by
A/D converter (ICS110B).
fixed!
50
0
-50
-100
-150
-1
10
0
10
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10
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10
Frequency[Hz]
3
10
4
10
5
10
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Improvement of PSL frequency noise
measured by 13-meter MC
Improvement of PSL frequency noise measured by MC
10
4
1
1/2
Frequency noise[Hz/Hz ]
10
10
10
10
10
10
10
3
2
3
2
 Meets the requirement
except for low frequency
and bump around 600Hz.
(Jan.22,2003)
10/07/2002 First measurement
10/17/2002 Ground loop
10/21/2002 Use feedback signal
11/09/2002 Turn off HEPA filter
12/16/2002 Increment of PMC gain
12/23/2002 Increment of Length gain
01/22/2003 Vibration of PSL table
PSL Requirement
1
5
4
0
-1
-2
6
7
-3
10
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Frequency[Hz]
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Noise budget of PSL frequency
noise measured by 13m MC
10
10
10
1/2
Frequency noise[Hz/Hz ]
10
10
10
10
10
10
10
10
10
10
10
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Noise budget of PSL frequency noise
8
Total PSL frequency noise measured by MC
Seimic noise
VCO phase noise
PSL Frequency noise measured by FSS
Coil driver noise
Intensity noise
Filter noise (Feedback)
Shot+Detector noise
Detector noise
PMC length noise
PSL Requirement
7
6
Bounce
mode
5
Cross over
frequency
4
Low frequency noise is
limited by seismic noise of
small stack of MC2.
Unknown noise around
100Hz (saturation of VCO
loop?).
Beam jitter noise on PSL,
Frequency noise and VCO
phase noise limit the high
frequency.
(Mar,10,2003)
3
Satiration on
VCO loop?
2
1
Frequency +
Beam jitter +
VCO phase noise
Beam jitter
0
Seismic Noise
-1
Coil driver noise, Intensity
noise, Feedback filter noise,
Shot noise and Detector
noise are lower than total
noise.
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-3
-4
-5
-6
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10
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Frequency[Hz]
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Estimation of PSL frequency noise
for 40m interferometer
-12
 -40dB Common Mode Rejection
Ratio (CMRR) is assumed.
 Measured residual frequency
noise of MC and measured OLTF
of MC are used.
 Need more CMRR or more OLTF
to reach the target sensitivity.
Contribution of PSL frequency noise for interferometer
10
Contribution of PSL frequency noise
(CMRR=40dB)
40m target sensitivity
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10
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-15
1/2
Strain sensitivity[1/Hz ]
10
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>>Actual estimation will be
performed by single arm cavity
later.
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Frequency[Hz]
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Core optics
BS ITMx
PSL
South Arm
Mode Cleaner
Detection
bench
ITMy
: Completed
East Arm
 ITMx, ITMy, BS optics hung,
balanced, installed, damped
in February 2003
 Begin commissioning of the
interferometer with 1 degreeof-freedom, short Michelson
: Installing
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Further Infrastructure
POx
TRx
AP1
 Remaining optical sensing
equipments of AP1, SP & MC,
Pox, POy, POb,TRx, TRy were
assembled in February 2003.
SP&MC
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Next 9 months
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Redesign of digital suspension controller using PCs for filtering.
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Assemble, hang, and install the four core suspended optics (PRM, SRM, ETMx,
ETMy) by 2Q 2003, and have them damped by the controller system.
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Begin commissioning of the interferometer in stages, with 1 degree-of-freedom
systems (short Michelson, Fabry-Perot arms) by 2Q 2003, even before a digital
length control system is installed.
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Fabricate and install auxiliary optics systems: scattered light control, initial
alignment system, optical levers, video monitoring.
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Fabricate and install LIGO I-like length sensing and control system.
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Fabricate and install the alignment sensing and control system.
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First experiments in dual recycled configuration response, lock acquisition, and
control are expected to take at least a year.
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Milestones revisited
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2Q 2002:
» All in-vacuum cables, feedthroughs, viewports, seismic stacks installed. Done
» 13m input MC optics and suspensions, and suspension controllers. Done
3Q 2002:
» Begin commissioning of 13m input mode cleaner. Done
» Acquisition of most of CDS, ISC, LSC, ASC. Done
4Q 2002:
» Core optics (early) and suspensions ready. Ten Suspension controllers. Some ISC. Done
» Glasgow 10m experiment informs 40m program In progress
» Control system finalized In progress
2Q 2003:
» Core optics (late) and suspensions ready. In progress
» auxiliary optics, IFO sensing and control systems assembled. In progress
3Q 2003: Core subsystems commissioned, begin experiments
» Lock acquisition with all 5 length dof's, 2x6 angular dof's
» measure transfer functions, noise
» Inform CDS of required modifications
3Q 2004: Next round of experiments.
» DC readout. Multiple pendulum suspensions?
» Final report to LIGO Lab.
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(Some) outstanding issues
and action items (40m, AdvLIGO)
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Any significant changes in people’s thinking re: optical configuration,
controls, CDS architecture??
166 MHz PD’s for WFS, LSC. Double demodulation(166  33 MHz).
Design servo filters for LSC, ASC
Detailed noise model (RSENOISE, Jim Mason)
Lock acquisition studies with E2E/DRLIGO. Develop lock acquisition
algorithms, software.
Triple-check thermal effects (Melody) – negligible?
Output mode cleaner – will PSL-PMC-like device be adequate? (For 40m,
for AdvLIGO). Suspended?
Offset-lock arms - algorithms, software.
DC GW PD – in vacuum? Suspended?
We expect that LSC members, as well as students,
will participate in this most interesting phase of the project.
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