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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 LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 1 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! LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 2 Differences between AdvLIGO and 40m prototype Initially, LIGO-I single pendulum suspensions will be used » » Only commercial active seismic isolation » » 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 » » 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 » » 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 » » 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 » » Due to shorter PRC length Less contrast between PRC and SRC signals LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 3 Target sensitivity of AdvLIGO and 40m prototype LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 4 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. LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 5 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. LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 6 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. LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 7 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 LIGO-G030033-00-R 1 10 2 10 Frequency[Hz] 3 10 4 10 5 10 40m Progress, LSC meeting, 3/03 8 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 1 LIGO-G030033-00-R 10 2 3 10 Frequency[Hz] 10 4 40m Progress, LSC meeting, 3/03 10 5 9 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 10 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. -2 -3 -4 -5 -6 10 0 10 1 LIGO-G030033-00-R 10 2 10 Frequency[Hz] 3 10 4 10 5 40m Progress, LSC meeting, 3/03 10 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 -13 10 -14 10 -15 1/2 Strain sensitivity[1/Hz ] 10 -16 10 -17 10 -18 10 >>Actual estimation will be performed by single arm cavity later. -19 10 -20 10 -21 10 -22 10 1 10 2 10 3 4 10 10 5 10 Frequency[Hz] LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 11 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 LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 12 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 LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 13 Next 9 months Redesign of digital suspension controller using PCs for filtering. Assemble, hang, and install the four core suspended optics (PRM, SRM, ETMx, ETMy) by 2Q 2003, and have them damped by the controller system. 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. Fabricate and install auxiliary optics systems: scattered light control, initial alignment system, optical levers, video monitoring. Fabricate and install LIGO I-like length sensing and control system. Fabricate and install the alignment sensing and control system. First experiments in dual recycled configuration response, lock acquisition, and control are expected to take at least a year. LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 14 Milestones revisited 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. LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 15 (Some) outstanding issues and action items (40m, AdvLIGO) 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. LIGO-G030033-00-R 40m Progress, LSC meeting, 3/03 16