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• Minutes20210816

ISC Meeting for ASC Strategies 2021/08/16 13:00 - 15:00

Participants: Shinji Miyoki, Naoki Koyama, Osamu Miyakawa, Terrence Tak Lun Tsang, Yoichi Aso, Tatsuki Washimi, Chiaki Hirose, Takafumi Ushiba, Kenta Tanaka, Marc Eisenmann, Hirotaka Yuzurihara, Yuta Michimura

Zoom meeting: https://zoom.us/j/5045179604

Your time zone: https://www.timeanddate.com/worldclock/fixedtime.html?iso=20210816T0400

Next meeting

TBD

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Minutes

• Possibility of shortening Xarm and Yarm commissioning
  • We decided to show the shortened version of the schedule and task list, and ask for suggestions.
  • Shortened task list
    • POP investigation, REFL WFS and POP WFS consistency check, arm cavity alignment to check mid-size baffle positions
    • Other tasks are postponed to FPMI commissioning in-vac
  • Things to ask for suggestions
    • Target values for mode matching and laser power throughput
    • Whether if we should adjust PR2 and PR3 to improve the mode matching in air
• Requirements for local damping
  • We need to check the status of coil drivers actually installed. For most of the suspensions, high power ones are currently used and this eases the requirement.
  • Nakano-kun said PRs are important for achieving the lock, but 7.3 um/sec requirement seems to be easily achievable. We need to check the current values.

  • For Type-A suspensions, <240 um/sec is the requirement for arm green locking, but there is another requirement coming from the central part locking. ITMs needs to be settled down to a level comparable to BS, SRs and PRs to lock recycling cavities (See text right below Table 5.1 in Sekiguchi thesis).

  • Let's set the requirement to be <0.44 um/sec for central part locking

• What we want to ask the reviewers?
  • Send Michimura an email if you have some suggestions.

Agenda

• External review next week! August 24, 2021 22:00-0:00 (JST)
• Requirements for local damping summarized

  • ITMs and ETMs (Type-A): <240 um/sec, <0.1 urad RMS

  • BS (Type-B): <1.6 um/sec, <1 urad RMS

  • SRs (Type-B): <0.44 um/sec, <1 urad RMS

  • PRs (Type-Bp): <7.3 um/sec, <1 urad RMS

  • References:

    • K. Okutomi PhD thesis (Table 3.5) JGW-P1809347

    • T. Sekiguchi PhD thesis (Table 5.2) JGW-P1504155

    • Y. Michimura et al (Section 6) Classical and Quantum Gravity 34, 225001 (2017)

• Possibility of shortening Xarm and Yarm commissioning?

  • http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/MIF/ExternalReview2021#agenda2

  • Latest schedule: https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9209

  • Strategy for the arm cavity commissioning while the central area is open
    • Should we adjust the position of the PR2 and PR3 to improve the mode matching to the arms at Xarm/Yarm commissioning periods? Or after the center area is evacuated?
• What we want to ask the reviewers?
• IMC ASC report? (Kenta, Chiaki)
  • To be discussed at the IMC ASC weekly on Wednesday