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

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Minutes

• KAGRA configuration for early phase of bKAGRA
  • SRM reflectivity
    • Metal mass design [Aso]
      • design almost complete, waiting for an estimate (roughly 100man-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] 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
  • 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?
      • First detection ASAP is our target, but we also have to consider what to do if we miss O3. It's harder to detect GW with single detector. Global coordination necessary.
    • 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] 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] 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] 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] 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] 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 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] (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 (JGW-T1605611)

  • Optickle simulation by Kohei Yamamoto 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 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 this page for other agendas.