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Participants: Enomoto, Koji Nagano, Kokeyama, Somiya, Michimura, Koji Arai Participants: Enomoto, Koji Nagano, Kokeyama, Somiya, Michimura, Koji Arai, Miyakawa

ISC Meeting on 2017/9/25 14:20 - 15:00

Participants: Enomoto, Koji Nagano, Kokeyama, Somiya, Michimura, Koji Arai, Miyakawa

Next meeting

2017/10/23 14:00 - 15:00

back to Meetings page


  • bKAGRA sensitivity update [Komori] JGW-T1707038

    • basically approved at EO on Sept 20
  • bKAGRA Phase 1 [Michimura]
    • initial alignment work starts on Oct 10; see MIF Commissioning page

    • no AS optics for Phase 1, instead use reflection REFL beam from PRM
    • we have to prepare REFL optics
  • 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

    • 50% reflectivity is better than default (85%) when input power is below ~30 W
    • A/Is
      • LSC and ASC check
      • excess noise at low frequency
      • schedule, budget, manpower
      • 2inch SRM quality
      • check how bad is PRFPMI with 85% misaligned or RSE with lossy SRC
  • IMMT1 and IMMT2 transmission [Michimura, Takeda]
    • IMMT2 transmission optics are too much squeezed
  • IR/green steering mirrors [Michimura]
    • will arrive at Mozumi on Sept 6
    • pedestals, mirror mounts
  • 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]
  • 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
      • 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
    • 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] (JGW-T1503453)

    • Summarized in the paper JGW-P1707051

      • waiting for Type-A seismic transfer function update [Okutomi]
    • 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.

KAGRA/subgroup/ifo/MIF/Minutes20170925 (last edited 2017-09-26 10:40:02 by YutaMichimura)