= ISC Meeting on 2017/11/6 14:00 - 15:00 = Participants: Aso, Enomoto, Hiro Yamamoto, Koji Arai, Koji Nagano, Hirose, Miyakawa, Kokeyama, Izumi, Somiya, Michimura eZuce meeting: "KAGRA ISC Meeting" in the KEK community. === Next meeting === 2017/11/20 14:00 - 15:00 [[LCGT/subgroup/ifo/ISC/Meetings|back to Meetings page]] == Minutes == * KAGRA configuration for early phase of bKAGRA * SRM reflectivity * Metal mass design [Aso] * design almost complete * estimate says roughly 15man-yen, 1-2 months * glue 2-inch SRM onto a ring, and fix the ring onto doughnut mass with screws * A/I: upload the design to JGWDoc by Nov 13 [Aso] * Sensitivity calculations [Enomoto] [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7078|JGW-G1707078]] * made noise vs input power plot necessary to achieve ~6 event/year (~40 Mpc for BNS, ~580 Mpc for BBH30) * MICH coupling is worse with lower reflectivity SRM * suspension thermal noise will be 2 orders of magnitude worse in room temperature case [by Somiya] * A/I: somehow compare with AdV　[Enomoto] * A/I: laser intensity/frequency noise coupling [Izumi] * 2-inch SRM estimate [Michimura,Hirose] * Asked to 2 companies. Roughly ~100man-yen. * We want it to arrive at least before the final phase of SRM installation (August 2018) * PRFPMI or RSE [Michimura] * PRFPMI with either spare ETM or real ETM will delay the overall schedule to make KAGRA compatible with GW detection * What is our target? Joining O3 or first detection ASAP? * We also have to consider what to do if we miss O3. It's harder to detect GW with single detector. Global coordination necessary. * Possibility of parallel work for joining O3? * A/I: sensitivity calculations for PRFPMI with spare ETM [Enomoto,Michimura] == Agenda == * bKAGRA Phase 1 [Michimura] * no AS optics for Phase 1, instead use reflection REFL beam from PRM * we have to prepare REFL optics * height of the beam from PR/BS breadboard will be 380 mm instead of 400 mm? * experiments for Phase 1 paper * bKAGRA Phase 2 schedule [Michimura] [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7079|JGW-T1707079]] * meeting with SEO on Sept 6 * Goal: 1 hour lock of cryogenic RSE with RF readout, probably with ASC, no sensitivity goal * input laser power not decided * when to swap ETM, SRM reflectivity, vacuum * schedule adjustment between AS WFS and OMC test necessary * SRM reflectivity for early phase of bKAGRA [Enomoto] [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7078|JGW-G1707078]] {*} * Sensitivity calculations [Enomoto] * Made excess noise vs input power plot necessary to achieve BNS range of 40 Mpc * SRM reflectivity of 70% seems least demanding in terms of excess noise and input power * A/I: redo calculation for BBH range (with estimate of event rate) [Enomoto] * LSC noise coupling calculation on going * UGF for auxiliary dof can be lower than 50 Hz [by Izumi] * MICH error signal from POP instead of MICH might be better considering phase flipping [by Izumi] * SRM surface quality [Hirose] [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7296|JGW-T1707296]] * MCe-level quality SRM will produce ~52 ppm (this estimate is based on surface quality without coating; coating could increase loss by x2 to x4) * A/I: SRM loss requirement for low reflectivity SRM [Michimura,Enomoto] * SRM metal mass [Aso] * overall mechanical components will cost roughly ~1M JPY [Aso] * composite mass could create unwanted resonance (at ~3 kHz in aLIGO case, with PEEK screw) * sensitivity for misaligning or adding extra loss with 85% SRM is worse than that for 0% SRM * A/Is * check LSC (and ASC) with different SRM reflectivity and incident power [Enomoto] * make a budget/manpower/schedule plan for SRM suspension with 2-inch mirror holder [Aso] * since there is already a BS dummy metal mirror suspension design, making similar system for SRM should be easy * 2-inch SRM [Michimura, Hirose] * asking some companies for estimate * loss function estimate [Hirose] [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7296|JGW-T1707296]] * make an overall budget/manpower/schedule estimate to reach 40 Mpc with different SRM reflectivity [Michimura] * bKAGRA Phase 1 spare ETM quality [Hirose,Michimura] [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7281|JGW-T1707281]] * 60ppm scattering, 200ppm coating absorption for ETMX * 287ppm scattering, 41ppm coating absorption for ETMY * is this compatible with RSE (and even PRFPMI)? {*} * IMMT1 and IMMT2 transmission [Michimura, Takeda] * IMMT2 transmission optics are too much squeezed * IR/green steering mirrors [Michimura] * mirrors arrived, mirror mounts and picomotor driver ordered, pedestals by Akutsu, vacuum cables by Aso * DC QPD holder [Michimura] * beam height should be 4inch to use similar mount, with small modification of spacer (instead of 3inch in [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2607|JGW-D1402607]]) * RF PD, RF QPD boxes are designed for 4inch beam height * stages are not needed for ISC DC QPD * design new ones; they can be very simple [-> Michimura?] * calibration can be done in different ways * put strain relief and anchors for cables to protect QPD board * OMC and OFI [Somiya] * look for OFI with larger aperture [Somiya] * DC PD and DC QPD [Michimura] * DC PD not available. Look for product with similar specs * DC QPD available from RS * In-vacuum RF PD and RF QPD {*} * we need them within 1 year, considering OMC REFL and AS RF * In-vac beam-dumps {*} * required spec? * PSL EOM Layout re-consideration [Enomoto] ([[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=6748|JGW-T1706748]]) * Delay-line length decided to be 2.66 m (instead of 8.88 m) * Modulation phase between f1 AM and PM is always aligned (we need this to be aligned) * Modulation index needed at each EOM is less than measured maximum index by Uehera ([[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=5611|JGW-T1605611]]) * Optickle simulation by Kohei Yamamoto [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7309|JGW-G1707309]] {*} * simulation on imperfections (MZ arm asymmetry, MZ lock, EOM phase difference control etc.) * start with hand calculation, simple setups, and then to full IFO simulation * Optickle model basically made, and checked with hand calculations * calculations for requirements on delay line lock displacement noise, parallel EOM MZ lock displacement noise, EOM modulation phase difference, EOM imbalance on-going * A/I: check phase noise calculations, requirements for f1 AM-PM mixed case [Kohei Yamamoto] * Requirement on carrier power loss? * Comment from Stefan Ballmer * Similar calculation was done in LIGO in the past. Displacement noise requirement for MZ was tough (~1e-14 m/rtHz). * Any in-air interferometer suffer from jitter and frequency noise which cannot be suppressed. * Actuator noise modeling [Michimura,Miyamoto] * Summarized in the paper [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7051|JGW-P1707051]] * Needs to implement frequency noise, but FSS modeling with ALS is complicated [student!] * Discuss mirror vibration from heat link {*} * Meeting on July 14 [Yamada, Miyamoto, Ushiba, Michimura] See [[KAGRA/subgroup/ifo/MIF/Minutes20170410|this page]] for other agendas.