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= ISC Meeting on 2020/06/15 12:30 - 13:30 = = ISC Meeting on 2020/06/15 12:30 - 14:00 =
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  * Probably FINESSE simulation is more urgent considering HOM effects are large with current ITMs

ISC Meeting on 2020/06/15 12:30 - 14:00

Participants: Haoyu Wang, Eleonora Caposcasa, Hiro Yamamoto, Keiko Kokeyama, Kentaro Somiya, Kiwamu Izumi, Koji Arai, Koji Nagano, Masayuki Nakano, Osamu Miyakawa, Shinji Miyoki, Ryutaro Takahashi, Tomotada Akutsu, Yoichi Aso, Yubo Ma, Takaaki Yokozawa, Yuta Michimura

Zoom meeting: https://zoom.us/j/7631499341

Time: https://www.timeanddate.com/worldclock/meetingdetails.html?year=2020&month=6&day=15&hour=3&min=30&sec=0&p1=248&p2=237&p3=4399&p4=137

Next meeting

TBD

back to Meetings page

Minutes

  • The latest KAGRA FINESSE file lives in https://granite.phys.s.u-tokyo.ac.jp/svn/LCGT/trunk/mif/Finesse_Simulations/

  • Calculations done by Somiya and Hiro show that the effect from BS thermal lensing is smaller than the effect from BS maps, which is smaller than ITM maps
    • Power at BS for bKAGRA design (670 W) is smaller than that for aLIGO design (5 kW ish?)
  • Bifrefringence simulation with FINESSE needs more work.
    • Two-world approach for DRMI could be OK, but some more tricks will be necessary for doing simulation with arms.

    • [A/I] Organize another meeting to discuss how to simulate s-p coupled interferometer [Michimura]

    • [A/I] Ask FINESSE developers for the possibility of modifying FINESSE to handle polarizations [Haoyu]

    • [A/I] Send current model with maps to Haoyu [Kokeyama]

  • Lack of manpower for simulating LSC
    • No one in KAGRA can run Optickle LSC right now
    • LSC sensing matrix from FINESSE seems strange
    • Probably FINESSE simulation is more urgent considering HOM effects are large with current ITMs

    • [A/I] Find people to work on LSC by Optickle or FINESSE [Michimura]

  • Measurements at the site
    • LSC sensing matrix measurement was done. Needs calibration.
    • RF transimpedance measurement can be done with shot noise limited light
      • DC power can be estimated with DC transimpedance and shot noise limited DC output
      • RF transimpedance can be measured by measuring the shot noise dependence on input DC power

      • Measured RF PD transimpedance also summarized in JGW-E1910675

    • Swept sine measurement for intensity noise coupling was done, but couldn't measure the coupling below ~100 Hz due to too much noise
    • Measurements to be done this week
      • PRC length
      • Schnupp asymmetry (measurement done a while ago was for 3 km Michelson with more noise)
      • etc.
  • Others
    • Is it OK to keep SVN public?

Agenda

  • New members

    • Haoyu Wang (University of Shanghai for Science and Technology) JGW-G2011697

    • Yubo Ma (Shanxi Datong University) JGW-G2011696

  • Useful links to know KAGRA interferometer design and status
  • Interferometer issues which require simulation studies
  • Status of simulation activities
  • Simulation activities necessary
    • LSC and ASC simulations with current ITMs and current interferometer setup
      • Especially LSC simulations not done for PRFPMI and DRMI, and 3f locking
      • Compare measured LSC and ASC sensing matrices with simulations
      • Compare measured recycling gain (for carrier and sidebands) with simulations
      • Compare measured AS mode content with simulations
      • Compare measured MICH/PRCL/SRCL controls noise coupling with simulations
      • Compare measured intensity/frequency noise coupling with simulations
    • Thermal lensing in BS
  • Measurements necessary to do simulation work
    • PRC (SRC) length and Gouy phase
    • Schnupp asymmetry
    • modulation depth (arm cavity scan)
    • arm cavity length (arm cavity scan)

    • arm cavity round-trip loss measurement with birefringence effect correctly taken into account (with PBS at POP/POS and TRX/TRY) JGW-T2011633

    • Power recycling gain for carrier and sidebands
    • Throughput from IMC output to AS RF, OMC DC, REFL, POP, TRX, TRY
  • Measurements necessary to compare the result with simulation

KAGRA/subgroup/ifo/MIF/Minutes20200615 (last edited 2020-06-15 15:21:06 by YutaMichimura)