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• Minutes20170619

ISC Meeting on 2017/6/19 14:00 - 15:00

Participants: Hirose, Aso, Kokeyama, Michimura (eZuce meeting)

Next meeting

2017/7/3 14:00 - 15:00

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Minutes

• Actuator noise modeling [Michimura]
  • Noise from heat links is one of the most interesting issues to be discussed
    • Ask people about the heat link vibration estimation status
• bKAGRA Phase 1 initial alignment
  • Poke Akutsu for baffle PD　for initial alignment use [Michimura]
• IR/green steering mirrors
  • No objections for proposed mirror specs

Agenda

• 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
    • meeting with him on June 6.
  • 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.
• OFI and OMC status? [Somiya]
  • look for OFI with larger aperture [Somiya]
  • output optics task sharing status?
  • OMC baseplate issue?

  • design review on June 26 at Titech

• Actuator noise modeling [Michimura,Miyamoto] (JGW-T1503453)

  • Updated magnet size for cryopayload marionette (ActuatorDesign wiki)

  • Updated lock acquisition section to derive velocity requirements for suspensions (see ISC Meeting minutes 20170410) [Michimura]

  • Needs to implement frequency noise, but FSS modeling with ALS is complicated [student!]

  • Paper?

• bKAGRA Phase 1 initial alignment / commissioning plan [Michimura]: JGW-T1605692

  • updated based on current schedule
    • ETMX and ETMY cryopayload installation almost at the same time
    • MICH lock at room temperature before cooling down (instead of cooling down ETMY first)
    • AS cannot be used for room temperature MICH lock (SR3 not ready)
    • SR2 won't be ready by the end of March 2018
  • Fixed mirrors for AS port (including SR2)
  • Some comments from the Chief Meeting
    • Revised schedule seems compatible with PRMI. Why not?

      • PRMI is an option after achieving the Phase 1 goal, if it doesn't delay the final bKAGRA JGW-T1605595

    • Initial alignment does not interfere with ITM Type-A installation work?
    • Evacuation of IXC/IYC compatible with Type-A installation work?
    • Initial alignment compatible with Pcal setup at EXA/EYA?

      • Meeting with Inoue on June 15

        • PD at EXA/EYA compatible with Pcal setup
        • Don't we need something like aLIGO baffle PDs for initial alignment after evacuation? Use Tcam (Pcal camera)?

• IR/green steering mirrors [Michimura] (see [kagra-isc 01649])

  • for POP/POS and green steering in PR2/SR2 chamber, needs picomotors and ~40 cm pedestals
  • need this by the end of August 2017 (after PR2 installation on June, before IR initial alignment starts on September)
  • proposed mirror specs
    • HR reflectivity: more than 99% for both 1064nm and 532nm
    • AR refectivity: less than 0.3 % for 1064nm, similar for 532nm
    • incient angle: 20-45 deg, s-polarization
    • radius of curvature: flat
    • size: 2-inch
    • wedge: 1 deg
    • substrate: Fused Silica
    • surface quality: λ/20, 0.1 nm rms roughness

See this page for other agendas.