= Simulation meeting 2021 Oct 14 15:00 =
Zoom2: https://zoom.us/j/6676627462

== Participants ==
Naoki Koyama, Marc Eisenmann, Matteo Leonardi, Osamu Miyakawa, Tomotada Akutsu, Yoichi Aso, Haoyu Wang

== Agenda ==
=== Updates from Projects ===
 * Birefringence
   * Slide for updates [[ https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=13335|link]]
   * We have calculated the overall energy conversion from S to P using the birefringence map. The calculated P power are smaller than measurements.
   * We also move the beam position on the mirror with a maximum decenter of 3cm. The loss of S power for ITMX is from 2.2% to 6.7%, for ITMY from 4.9% to 13.2%.
   * The loss of S can be reduced if the beam spot is slight decentered (maybe 1cm). But 1cm decenter may be too large for KAGRA.
   * Matteo pointed out that the rotation angle in TWE measurement is not accurate. We need to check the real rotation angle by checking the original map files (by looking at the ears of the mirror).
   * We also calculated the single bounce beam shape using FINESSE. The computation cost 4 days for Maxtem 20 and around 15 days for Maxtem 30. Maxtem 20 may be enough as the error is less than 1%. Marc pointed out that the computation would be faster if we reduce the resolution of the map.


 * GUI
   * Koyama-san is reviewing the codes, functions and definitions in FINESSE.

 * Pygwinc
   * The latest version of Pygwinc is the one 2 years ago, which is out of date. [[ https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9952|link]]
   * Marc is thinking to modify some part of it for the frequency dependent squeezing.
   * Whether some new important noises should be added?
   * Some parameters may be not correct. We are probably under estimating the coating thermal noise.
   * Shall we improve the user friendly interface?