ISC Meeting on 2021/06/28 14:00 - 15:00

Participants: Keiko Kokeyama, Chiaki Hirose, Kiwamu Izumi, Masayuki Nakano, Ryosuke Sugimoto, Satoshi Tanioka, Yoichi Aso, Tomotada Akutsu, Kenta Tanaka, Shoichi Oshino, Hiroaki Yamamoto, Shinji Miyoki, Osamu Miyakawa, Yuta Michimura

Zoom meeting: https://zoom.us/j/6676627462

Your time zone: https://www.timeanddate.com/worldclock/fixedtime.html?iso=20210628T0500

Next meeting

TBD

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Minutes

• Phase camera project [Kokeyama]
  • How to get the reference beam?
    • IR fiber is already there at POP/POS (main + spare for green, two for IR; 4 fibers in total for each table)
  • Speed of phase camera?
    • Important if we use the signal for some alignment control etc.
    • At Virgo, it was ~ 1 shot / 1 sec. Daniel Brown et al at Adelaide are making faster ones.
  • Discuss more after result comes out (October-ish)
  • Optical table layout and electronics needs to be checked
    • Maybe we need such device anyway at some point

  • DECISION KAGRA ISC supports the proposal

• ALS report [Izumi]
  • Arm locking section of the users manual is not finished.

    • A/I: Talk with Nakano etc. to complete the manual [Izumi]

  • Noise level of PLL control/error signals are somehow breathing

  • A/I: Remind Tanioka about the procurement of items related to alignment [Michimura]

• IMC ASC report [Kenta, C. Hirose]
  • Control strategy needs to be re-checked.
  • Analytical calculation and FINESSE simulation result do not match completely.

  • A/I: Check the calbiration of A2L coupling factor and the status of coil balancing.

• IMMT1T ISS POM [Michimura]
  • There is another uncertainty on the loss introduced at the viewports (AR specified only at 0 deg incidence).

  • DECISION We will go for 90:10.

Agenda

• IMC ASC [Kenta, C. Hirose, 20 min] https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=13047　ISCmeeting_0628_hirose.pdf

• Phase camera project [Kokeyama, 10 min] slide

• ALS report [Izumi, 10 min]

  • ALS users manual https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=13031

  • Remaining tasks for ALS https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=13042

• IMMT1T ISS POM spec (see below) [Michimura, 10 min]

• O4 commissioning task list [Izumi, Michimura]

  • Any missing items?
• Other reports

  • Non-polarizing beam splitters for in-air optical tables ordered https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=12956 [Michimura]

  • In-vac steering mirrors: https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=12592 [Michimura]

    • IMMT1T ISS POM: Spec to be finalized

      • R:T=90:10 for 1064 nm, transmissive for oplev beam (663-675nm) https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=12949

        • 0.2963% @ 1064 nm measured by the vendor. 0.22% measured by Akutsu-san at the site.
        • Need to check again if ISS people is happy about R=90%
      • Wedge finalized to be 1 deg (wedge side is HR)
    • All reflective steering mirrors: Spec to be finalized
      • Order AoI=0-30 deg ones and AoI=30-50 ones
      • Wedge finalized to be 0.5 deg
  • Optical table cover [Michimura]
    • IMC TRANS assembled, IMC REFL delivered
    • Parts for fixing FFU on REFL, POP, AS ordered
    • TRX and TRY ordered
    • Additional small FFU for POS ordered