= Simulation meeting 2021 Oct 28 15:00 =
Zoom2: https://zoom.us/j/6676627462

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

== Agenda ==
=== Updates from Projects ===
 * Birefringence
   * FINESSE simulation for single bounce beam shape with Maxtem of 30 is almost the same as Masxtem of 20.
   * ITM rotations in map measurements before coating and after coating are different. We should use maps after coating. But areas of maps after coating are small and we cannot see the flat edges of mirrors. 
   * TWE map measurements are difficult due to multiple internal reflections. KAGRA TWE maps should be measurements after coating.
   * Check S1thruS2 maps. These are maps before coating. In general, TWE measurements are difficult for uncoated mirrors.
   * Maybe it is a good idea to infer the mirror rotation by looking at Zernike tilt coefficients.
   * Check HR maps. Check if there are any common patterns in different rotations.
   * We don’t know if the TWE map data files represent the one-way phase delay or round-trip phase delay. Normally, it should be round-trip phase delay as they are raw files. For our simulation, if we regard it as round-trip phase, the calculated birefringence loss is much smaller than KAGRA measurement. If we regard it as one-way phase delay, it will match with KAGRA loss measurement. So we don’t know if the TWE map data is calibrated to one-way phase delay in the measurement, or there are something wrong with our method.

 * GUI
   * Now the GUI can tune the demodulation phase and find the optimal demodulation phase.
   * We can set the quality factor and mechanical resonance frequency of the mirror now.
   * Shot noise and radiation pressure noise detections are implemented. We are still testing it.

 * Pygwinc
   * Marc is trying to simulate O3GK sensitivity using Pygwinc, comparing it with Michimura-san’s calculation.
   * Some parameters e.g., temperature and power are changed.