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

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

Next meeting

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

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Agenda

• 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 trasmission [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.