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

Participants:

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 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
- 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)