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= ISC Meeting on 2020/07/06 13:30 - 14:00 = = ISC Meeting on 2020/07/06 13:30 - 14:30 =
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TBD When necessary
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 * 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 [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10675|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?
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 * New members
  * Haoyu Wang (University of Shanghai for Science and Technology) [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11697|JGW-G2011697]]
  * Yubo Ma (Shanxi Datong University) [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11696|JGW-G2011696]]		  * Summary of current measurements so far
  * LSC sensing matrix, measurements vs simulation
   * Optickle simulation: https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11767
    * Parameter choice of "BRSE_SDMR1_17_45" OK?
   * Measurements: https://klog.icrr.u-tokyo.ac.jp/osl/?r=14515, https://klog.icrr.u-tokyo.ac.jp/osl/?r=14593
  * Schnupp asymmetry measurements
   * Time of flight measurement successful https://klog.icrr.u-tokyo.ac.jp/osl/?r=14575
  * PRC length measurements
   * PRY length: 68.28 m with the error of roughly 1 m (designed: 64.926 m) https://klog.icrr.u-tokyo.ac.jp/osl/index.php?r=14555
   * PRX length: about 68 m https://klog.icrr.u-tokyo.ac.jp/osl/?r=14633
   * Actuator efficiency inconsistent between measurements?
  * OMC scan to see mode content of AS beam
   * With X-arm locked https://klog.icrr.u-tokyo.ac.jp/osl/?r=14620
   * carrier and f1 3rd mode is overlapped?
 * Birefringence simulations with FINESSE
  * Any volunteer to add polarization to FINESSE code?
  * "directional beamsplitter" could be used to simulate DRFPMI with FINESSE using s/p two-world approach
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 * Useful links to know KAGRA interferometer design and status
  * List of optical parameters [[LCGT/subgroup/ifo/MIF/OptParam|OptParam]]
  * MIF Design document [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=913|JGW-T1200913]]
  * Interferometer design paper [[https://journals.aps.org/prd/abstract/10.1103/PhysRevD.88.043007|Phys. Rev. D 88, 043007 (2013)]]
  * Latest KAGRA status paper [[https://arxiv.org/abs/2005.05574|arXiv:2005.05574]]
  * Summary of measurements related to the interferometer so far [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/subgroup/ifo/MIF/Minutes20200309|Minutes20200309]]
  * O4 schedule [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9209|JGW-E1809209]]
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 * Interferometer issues which require simulation studies
  * ITMs have different transmission (ITMX: 0.444 % ITMY: 0.479%) [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=10352|JGW-T1910352]]
  * ITMs have inhomogeneity [[https://doi.org/10.1103/PhysRevD.100.082005|Phys. Rev. D 100, 082005 (2019)]]
  * ITMs have inhomogeneous birefringence [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=10369|JGW-G1910369]], [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=10388|JGW-G1910388]], [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=11633|JGW-T2011633]]
  * So far no success in locking DRFPMI [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11693|JGW-G2011693]]
  * WFS not working well [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11687|JGW-G2011687]]
  * Laser intensity and frequency noise couplings are too high [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11662|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 [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=11633|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 [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=913|JGW-T1200913]]
   * Simulations for O3 by Yutaro Enomoto [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10341|JGW-T1910341]]
   * Mach-Zehnder modulator simulations by Kohei Yamamoto [[https://doi.org/10.1088/1361-6382/ab4489|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 [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=913|JGW-T1200913]]
   * Simulations for O3 by Yuta Michimura [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=10359|JGW-T1910359]]
  * FINESSE model originally by Kentaro Somiya [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=2434|JGW-T1402434]] (any updated version?)
   * Used for OMC design [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=8043|JGW-T1808043]], [[https://link.springer.com/article/10.1007/s10043-015-0028-2|Optical Review 22, 149-152 (2015)]], [[https://iopscience.iop.org/article/10.1088/1742-6596/957/1/012009|J. Phys.: Conf. Ser. 957, 012009 (2018)]]
   * ITM inhomogeneity effects [[https://doi.org/10.1103/PhysRevD.100.082005|Phys. Rev. D 100, 082005 (2019)]]
   * Also being used for simulating birefringence effects by Keiko Kokeyama [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=10461|JGW-G1910461]], [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=10380|JGW-T1910380]]
  * Parametric instability by Kiichi Kaihotsu, Kazuhiro Yamamoto
   * Activities in University of Toyama using COMSOL [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/DocDB/ShowDocument?docid=10382|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)
 === Copy from previous meeting ===

ISC Meeting on 2020/07/06 13:30 - 14:30

Participants:

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

Time: https://www.timeanddate.com/worldclock/meetingdetails.html?year=2020&month=7&day=6&hour=4&min=30&sec=0&p1=248&p2=237&p3=4399&p4=137

Next meeting

When necessary

back to Meetings page

Minutes

Agenda

Copy from previous meeting

  • 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/Minutes20200706 (last edited 2020-07-06 16:26:33 by YutaMichimura)