ISC Meeting on 2020/06/15 12:30 - 13:30

Participants: Haoyu Wang, Eleonora Caposcasa, Hiro Yamamoto, Keiko Kokeyama, Kentaro Somiya, Kiwamu Izumi, Koji Arai, Koji Nagano, Masayuki Nakano, Osamu Miyakawa, 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

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Minutes

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

  • List of optical parameters OptParam

  • MIF Design document JGW-T1200913

  • Interferometer design paper Phys. Rev. D 88, 043007 (2013)

  • Latest KAGRA status paper arXiv:2005.05574

  • Summary of measurements related to the interferometer so far Minutes20200309

  • O4 schedule JGW-E1809209

• Interferometer issues which require simulation studies

  • ITMs have different transmission (ITMX: 0.444 % ITMY: 0.479%) JGW-T1910352

  • ITMs have inhomogeneity Phys. Rev. D 100, 082005 (2019)

  • ITMs have inhomogeneous birefringence JGW-G1910369, JGW-G1910388, JGW-T2011633

  • So far no success in locking DRFPMI JGW-G2011693

  • WFS not working well JGW-G2011687

  • Laser intensity and frequency noise couplings are too high JGW-T2011662

  • Carrier power recycling gain for PRMI (roughly 3) and PRFPMI (11-12) are too different, which could be due to the Lawrence effect JGW-T2011633

• Status of simulation activities

  • LSC simulations with Optickle originally by Yoichi Aso https://granite.phys.s.u-tokyo.ac.jp/svn/LCGT/trunk/mif/IFOmodel

    • Used for designing the interferometer, and deriving requirements JGW-T1200913

    • Simulations for O3 by Yutaro Enomoto JGW-T1910341

    • Mach-Zehnder modulator simulations by Kohei Yamamoto Classical and Quantum Gravity 36, 205009 (2019)

  • ASC simulations with Optickle originally by Yuta Michimura https://granite.phys.s.u-tokyo.ac.jp/svn/LCGT/trunk/mif/ASC-Optickle

    • Used for designing the interferometer JGW-T1200913

    • Simulations for O3 by Yuta Michimura JGW-T1910359

  • FINESSE model originally by Kentaro Somiya JGW-T1402434 (any updated version?)

    • Used for OMC design JGW-T1808043, Optical Review 22, 149-152 (2015), J. Phys.: Conf. Ser. 957, 012009 (2018)

    • ITM inhomogeneity effects Phys. Rev. D 100, 082005 (2019)

    • Also being used for simulating birefringence effects by Keiko Kokeyama JGW-G1910461, JGW-T1910380

  • Parametric instability by Kiichi Kaihotsu, Kazuhiro Yamamoto

    • Activities in University of Toyama using COMSOL JGW-E1910382

  • Thermal lensing by Kentaro Somiya ?
    • Thermal lensing in cryogenic sapphire mirrors should be small (orders of magnitude smaller than room temperature fused silica)
    • Thermal lensing in room temperature fused silica BS needs investigation
      • Rough estimation by Hiroaki Yamamoto shows it is OK-ish, comparing the result with aLIGO
      • Further investigation necessary (also for future higher power)
• 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
  • frequency/intensity noise coupling, down to ~10 Hz
  • Measure power recycling gain for sidebands (POP 2f with FPMI locked and PRFPMI locked)
  • DRFPMI LSC and ASC sensing matrix

    • LSC https://klog.icrr.u-tokyo.ac.jp/osl/?r=14515

  • MICH/PRCL/SRCL to DARM coupling
  • Measure MICH contrast defect with MICH locked and FPMI locked
  • OMC cavity scan to scan mode content of AS beam

  • https://docs.google.com/spreadsheets/d/1w4q8OvX9E6nkYSgshLYLoZH5yvQXHvGmL1agux8ztx0/edit#gid=0

  • Type-A, B, Bp actuation efficiency measurements (for actuator noise)