1 / 41

Report to the 40m Technical Advisory Committee February 9, 2006 The 40m Team

Report to the 40m Technical Advisory Committee February 9, 2006 The 40m Team Ben Abbott, Rana Adhikari, Dan Busby, Jay Heefner, Osamu Miyakawa, Mike Smith, Bob Taylor, Monica Varvella, Steve Vass, Rob Ward, Alan Weinstein

eneighbors
Download Presentation

Report to the 40m Technical Advisory Committee February 9, 2006 The 40m Team

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Report to the 40m Technical Advisory Committee February 9, 2006 The 40m Team Ben Abbott, Rana Adhikari, Dan Busby, Jay Heefner, Osamu Miyakawa, Mike Smith, Bob Taylor, Monica Varvella, Steve Vass, Rob Ward, Alan Weinstein with lots of help from: Matt Evans, Helena Armandula, Rolf Bork, Alex Ivanov, SURF students, etc… 40m TAC, 10/13/05

  2. October: RSE • The last meeting of our TAC was October 13, 2005. • On October 14, Osamu brought the interferometer into full lock, with RSE, and the arms at full resonance (negligible CARM or DARM offsets). • He was able to hold lock for many minutes, and regain lock when lost. • Working independently and with somewhat different strategy, Rob, Rana and Matt brought the interferometer into full lock • used the POX RF signal to control the analog common mode servo • holding for hours, regaining lock easily. • Rob and Matt automated the lock acquisition procedure. • Both Osamu and Rob/Rana/Matt took CARM and DARM transfer functions, noise spectra, etc. • There was a clear RSE peak in DARM, no optical spring peak. 40m TAC, 10/13/05

  3. RSE and optical spring • Osamu realized that we aren't seeing the optical spring peak in the DARM transfer function because we were locking the signal recycling cavity in the wrong place, on the "other side" of the spring (so that it's an anti-spring). • He flipped the sign of the SRC servo loop, then flipped the sign of several more loops before he was able to regain full lock in the AdLIGO configuration. And there, in addition to the clear RSE peak at ~ 4 kHz, was a beautiful optical spring peak at ~ 40 Hz! • Rob, independently, arrived at exactly the same set of sign flips to achieve lock in the optical spring configuration. 40m TAC, 10/13/05

  4. Optical response (correcting for pendulum, filtering), with fit to Buonanno & Chen formula DARMin1 / DARMout ---------------------------- XARMin1 / XARMout times arm cavity pole. Yields optical response, taking out pendulum, analog & digital filtering, etc. XARM TF is understood semi-quantitatively. Offset-locked CARM also has optical spring peak, also well modeled. Anti-spring TF also well modeled. Description of data, fit: http://www.ligo.caltech.edu/~cit40m/Docs/40mTF_060207.pdf P060007-00-R. Where to publish? 40m TAC, 10/13/05

  5. CARM optical springs • Solid lines are from TCST • Stars are 40m data • Max Arm Power is ~80 • Also saw CARM anti-springs 40m TAC, 10/13/05

  6. Optical spring in E2E • Calculated by time domain simulation • Demod phase of 10 is a guess; needs tweaking • Calculation time ~5min using DRMI summation cavity 40m TAC, 10/13/05

  7. h arm cavity h Beam splitter D arm cavity laser Signal recycling mirror b a Mathematical description for optical spring in detuned RSE a :input vacuum b :output D :input carrier M :constant h :gravitational wave hSQL:standard quantum limit t: transmissivity of SRM k: coupling constant F: GW sideband phase shift in SRC b: GW sideband phase shift in IFO Measurement of optical transfer function a<<h; non-quantum measurement 40m TAC, 10/13/05

  8. Fdet (=4kHz at 40m) FWHM fsig Sideband amplitude at output [a.u.] LSB USB Signal sideband frequency offset from carrier [Hz] Simple picture of optical resonance • Response between GW USB and GW LSB is different due to the detuned signal recycling cavity. • the resonance of the SR cavity and is maximally enhanced for • fsig = fdet Carrier frequency 40m TAC, 10/13/05

  9. Simple picture of optical spring in detuned RSE Let’s move arm differentially, X arm longer, Y arm shorter from full RSE Wrong SRM position Correct SRM position BRSE X arm Y arm Y arm X arm Power(W) Power(W) Power(W) DARM (Lx-Ly) DARM (Lx-Ly) DARM (Lx-Ly) • Power X arm down, Y arm up X arm down, Y arm down X arm up, Y arm down • Radiation pressure X arm down, Y arm up X arm down, Y arm down X arm up, Y arm down • Spring constant Negative(optical spring) N/A Positive(no optical spring) 40m TAC, 10/13/05

  10. Darker AP • In this correct locking point, the spot at AP is now much nicer: rounder, and the optical spectrum analyzer shows that the carrier is now nearly dark. It looks like the correct locking point exhibits "mode healing", while the wrong locking point exhibits "mode damaging". Repeatable. • anti-spring spring • Osamu gave a LIGO/Caltech seminar on the Optical spring and optical resonance in the 40m Detuned RSE interferometer, on November 1. G050568 40m TAC, 10/13/05

  11. MOPA changes • On November 6, in response to a plea from Mike Zucker, we packed up our 10 Watt MOPA # 118 (“Asissi”) and shipped it to LLO. • By November 8, it was installed, delivering 8.9 W, and L1 had an inspiral range of 10.4 Mpc. • Replacement laser (old H2, MOPA #102 ) arrived November 28. There were a variety of differences, requiring some reworking • water cooling re-plumbing and leak fixing. • NPRO temperature scan. • 5.4W with the calorimeter at the exit of the MOPA. • Implement SLOW loop actuator, and servo. • We installed a phase-correcting EOM external to the MOPA, as at the sites. • Rearranged some optics for easy steering into PMC. • Mode matched into the PMC. • Replaced old FSS with new TT FSS. • More light on PMCR RFPD, ISS DCPDs. • Tuned up FSS, PMC and ISS servos. • PMC transmission is significantly lower than before, not sure why. • Re-aligned beam through Mach Zehnder, IOO, periscope, mode cleaner. • Finally back up with locked mode cleaner and arms by December 20. • Full lock, once again, by Jan 5. 40m TAC, 10/13/05

  12. While we were laser-less (1) Osamu re-measures seismic noise at 40m, builds new model of stack TF, and new noise prediction. Osamu starts thinking about calibration with the more complex optical plant. 40m TAC, 10/13/05

  13. While we were laser-less (2) • DAQ RAID array failed at end of November; replaced. • 3.7 years of minute trends feared lost. • Alex Ivanov recovers the minute trends after a month of heroic effort. • Now all minute trends (and EPICS snapshots, online code, etc) backed up nightly. • Rana evaluated our PMC, MC, and CM servo boards. All need to be updated / replaced. New boards are now in hand. • Many new DAQ channels added. • Rob attended QND workshop at Hannover in December. He gave talks on the optical spring as observed at the 40m, various modeling tools used to understand the AdvLIGO configuration, and his new modeling tool OpTickle. • Osamu, Dan, Ben take S5 shifts • New coffee maker purchased. Productivity takes a leap. 40m TAC, 10/13/05

  14. Deterministic Locking • Rob, Rana, Matt are developing schemes to lock the full IFO in a smooth, controlled, deterministic way (“no-bang locking”). • These steps involved mis-aligning and re-aligning the recycling mirrors. At each stage, more degrees of freedom are brought into lock in a controlled way. • Normalized DC signals are used to minimize interference between changing IFO state and LA control signals. • Real-time LSC code was cleaned up, and made more flexible for new LA approaches. • LSC rack got some re-cabling to get more DC signals into the system. • There is now a scheme to deterministically lock the PR-FPMI, with the carrier not fully resonant. The procedure is very repeatable and easy. • Attempts to add the SRC have so far failed. Work, and thinking, is in progress. 40m TAC, 10/13/05

  15. DC readout progress • We have acquired almost all of the parts we need: • two in-vac PZT steering mirrors (SRM  OMMT) • output mode-matching telescope (designed/built by Mike Smith) • in-vac folding mirrors • monolithic 4-mirror OMC, mirrors, UHV-PZT for length actuation • DC PD monolithic base, electronics in vacuum can • breadboard to pre-align in-vac optics • SR 830 Lock-In Amplifier to lock OMC • Still under development: • PZT driver for OMC • PZT drivers for in-vac steering mirrors • steering mirror ASC controls • Front-end wiring, EPICS wiring, DAQ channels • Plan to be ready to install by end of March 40m TAC, 10/13/05

  16. Output mode cleaner, DC PD OMC:Monolithic, copper, 4-mirror design. DCPD:Monolithic, electronics in vacuum nipple 40m TAC, 10/13/05

  17. Coming milestones (1) • re-establish robust lock of the dual-recycled FPMI, after the replacement of our laser (just about done); • re-measure and understand the detector response (one week); • develop and implement more robust "deterministic” locking strategies (open-ended, but one Feb-April is our plan); • learn how to tune the detector response for optimal sensitivity and control, by measuring and adjusting things like demod phases and offsets; (open-ended, but one Feb-April is our plan); • calibrate the detector and measure the displacement noise spectrum (Feb); • develop a "noise budget" to identify, and hopefully reduce, the dominant sources of technical noise (March, and on-going); 40m TAC, 10/13/05

  18. Coming milestones (2) • assemble, install, commission and study the behavior of a DC readout system, including the tuning (offsets, etc) and the noise contributions (March-June); • Develop plans for injecting squeezed vacuum into the 40m asymmetric port, using a squeezer to be brought from MIT by Keisuke Goda and Nergis. Begin experiments by summer? • Continue development of e2e models and Optickle QN frequency-domain model. • Prototype ASC/WFS solutions • going to lower f2 RF ? 40m TAC, 10/13/05

  19. Squeezed vacuum experiment • Vacuum squeezer apparatus developed by Nergis, Go and company at MIT • Go plans to bring his vacuum squeezer to the 40m lab this spring, with the goal of injecting squeezed vacuum into the 40m interferometer by this summer, and observe reduction in quantum (shot) noise… IF 40m is shot-noise limited at squeezing frequency. • OPTIMISTICALLY, the work could proceed in parallel with AdvLIGO goals (lock acquisition & control, DC readout). • Based on this optimistic assessment, it would be worthwhilefor Go to visit, starting in March. • Even if we aren't injecting squeezed vacuum by this summer, we will make good use of Go's visit, helping reduce noise. 40m TAC, 10/13/05

  20. Go’s schedule 40m TAC, 10/13/05

  21. Possible layout of squeezer, readout 40m TAC, 10/13/05

  22. Two squeezing experiments • MHz squeezing test in the semi-Advanced LIGO configuration, meaning a detuned RSE with the power recycling mirror (PRM), but without the output mode cleaner (OMC) • “low-frequency” squeezing test in the Fabry-Perot Michelson (FPMI) configuration. 40m TAC, 10/13/05

  23. What we need from TAC • Comments on paper on 40m response • Advice on squeezing experiment • Advice on replacing MZ with single EOM • Paper on MZ for eliminating sidebands-on-sidebands in preparation by Bryan Barr • Words of encouragement 40m TAC, 10/13/05

  24. Some optional slides on synthesizing Mach-Zehnder 40m TAC, 10/13/05

  25. No sidebands on sidebands with Mach-Zehnder • With two EOMs in series to generate PM sidebands at f1 and f2, get “sidebands on sidebands” at f1 ± f2 • We use MZ to generate sidebands in parallel f2 f1 40m TAC, 10/13/05

  26. Synthesize MZ? • The MZ adds complexity and noise. Can we do it with one EOM? • The PM waveform that must be input to a single EOM to produce f1 and f2 with no f1 ± f2 : • required waveform: Synthesized: 40m TAC, 10/13/05

  27. The synthesized waveform does the job! • BUT it can’t be done with pure PM; it involves complex coefficients (AM). 40m TAC, 10/13/05

  28. Can it be done with pure PM? • Using only real sines and cosines: • Doesn't work: -4f and -6f are suppressed, but +4f and +6f are not. 40m TAC, 10/13/05

  29. Extra, older slides 40m TAC, 10/13/05

  30. Requirement of RMS noise for full lock (10% of FWHM of RSE) Noise investigation in DRMI+single arm (no CM servo) 40m TAC, 10/13/05

  31. DC Readout at the 40m • DC Readout eliminates several sources of technical noise (mainly due to the RF sidebands): • Oscillator phase noise • Effects of unstable recycling cavity. • The arm-filtered carrier light will serve as a heavily stabilized local oscillator. • Perfect spatial overlap of LO and GW signal at PD. • DC Readout has the potential for QND measurements, without major modifications to the IFO. • We may not be able to see shot noise at low frequency, given our noise environment. We may not even see any noise improvements, but we might! • The most important thing we will learn is : How to do it • How to lock it? • How best to control the DARM offset? • What are the unforeseen noise sources associated with an in-vacuum OMC? • How do we make a good in-vac photodiode? What unforeseen noise sources are associated with it? 40m TAC, 10/13/05

  32. DC readout equipment • Most in-vac optics and opto-mechanics have been ordered • Most mirror mounts and mirrors • Output mode-matching telescope with picomotor focus • two Piezo-Jena steering mirrors • The PZT drivers are under design by Jay Heefner (also maybe needed at sites for RBS system); based on IO PZT drivers. Need strain gauge readback. • OMC design from Mike Smith • 4-mirror design • super-mirrors with REO coatings coming from LIGO Lab spares • DC PD assembly and electronics under design (Abbott, Adhikari) • OMC control, DC PD readout, and monitoring electro-optics and readout, under design (Heefner), mostly using existing infrastructure and equipment. • Alignment on bench, in air, and in vacuum seems feasible. Mount everything on breadboards, install into vacuum chamber as a unit. 40m TAC, 10/13/05

  33. Output Optical Train 1st PZT steering mirror gets a little tight around IMMT SRM 2nd PZT steering mirror BSC OOC IOC Mike Smith 40m TAC, 10/13/05

  34. Output Optic Chamber Existing in-vac seismically isolated optical table (OOC) to OMCR beamline Mike Smith has designed a compact, monolithic MMT, similar to our input MMT, using spherical mirrors. 4-mirror monolithic OMC. Pair of DC PDswith in-vac electronicson monolithic base. from SRM 2nd PZT steering mirror PZT steering mirrors and their controls are duplicates of a pair that we have already installed and commissioned for steering from IMC to main IFO (in-vac); controls are fully implemented in the ASC system (by Rolf). Similar systems can be used for “LIGO I.V”. Piezosystem Jena PSH 5/2 SG-V, PZT tilting mirror mount with strain gauge, and associated drivers and power supplies to OMCT beamline IMCR, IMCT, and SP beamlines to AS RF beamline (roughly 1/3 of AS power) also a convenient path for autocollimator beam, for initial alignment in air from PSL to IMC Mike Smith 40m TAC, 10/13/05

  35. OMC design in SolidWorks • Small number of pieces • HV compatible • a bit of glue on the PZT mirror • Mirrors mounted mechanically, on silver washers (no glue) • ALGOR FEA: lowest mech resonance at ~770 Hz • Construct out of well-damped material, to minimize effect of resonances • Brass? Copper? • Or just stick with aluminum? • All high-quality (REO super-polished and coated) mirrors available from LIGO lab spares (well, the 4th HR mirror, 0o incidence, may need to come from Newport) From MMT reflected beam SS fixed spacer PZT mirror ~ 20 cm mechanical clamps (no glue) Mike Smith to DCPD 40m TAC, 10/13/05

  36. Low-loss mirrors • The TAC encouraged us to consider low-loss mirrors for our OMC (eg, super-polished, REO coatings, etc). • The PZT-mounted curved mirror will be supplied by Peter King, out of PMC spares. • Helena worked with REO for the remaining required mirrors + spares: ~$7K, 6 weeks. • Peter F asked around: LHO has spare PMC mirrors with T=1.4%, and HR mirrors (43.5o incidence P-pol). • Our “4th” mirror needs to be HR at ~10o incidence P-pol. We will test the HR mirrors to see if they work. Else, we can get Newport “super-polished” broadband mirrors for ~$475, with R~99.95%. 40m TAC, 10/13/05

  37. In-vac DC photodiodes Ben Abbott In-vacuum DC PD assembly, showing a 50% beamsplitter, two photodiodes, a beam-dump, and a vacuum can to hold electronics. Electronics under design (Abbott, Adhikari) 40m TAC, 10/13/05

  38. Development of e2e simulation:4Om/AdvLIGO package • Monica Varvella (visitor from LAL/Orsay) has developed a 4Om/AdvLIGO package with a DRFPMI optical plant, and is developing the control plant with help from Matt Evans and Hiro Yamamoto • Tests include a careful comparison with Twiddle, as well as comparison of error signal sweeps between simulation and 40m data. • Can be used to extract the velocity of the mirrors in the 40m under controlled circumstances: lock all degrees of freedom, CARM offset, and then HOLD the CARM servo and watch error signal as mirrors sweep through arm resonance. 40m TAC, 10/13/05

  39. e2e SIMULATION:4Om/AdvLIGO package Error signal sweeps at 10-9 m/s for the 40m IFO obtained in E2E framework and compared with TWIDDLE predictions TWIDDLE E2E Example: DARM @ AP166 MHz TWIDDLE and E2E comparison 40m TAC, 10/13/05

  40. e2e SIMULATION:4Om/AdvLIGO package Real data have been used to estimate relative mirror velocity for both the arms: Vxarm= (0.35 ± 0.13)μm/s Vyarm= (0.26 ± 0.13)μm/s Tr X E2E real data Comparison between real data (black) and e2e simulated data (red) of the transmitted light for both the arms (full IFO): the mirror velocities used in E2E simulation are the values obtained fitting the real data Tr Y real data E2E 40m TAC, 10/13/05

  41. e2e SIMULATION:4Om/AdvLIGO package Comparison between real data , e2e simulated data and the theoretical prediction V(t) of the SP error signal @ 166 MHz V(t) ~ exp(-t/τ) sin( a t2) with a = -(k v) / (2 T) The τand the velocityvis the value obtained fitting real data τ = 0.7 ms v = 0.26 μm/s 40m TAC, 10/13/05

More Related