== CAL Meeting on 2017/7/31 18:00-  ==
Participants : B.H.Hsieh, Y.Inoue, N.Kanda, Y. Moriwaki, T.Shishido, T.Tomaru, T.Yamamoto, T.Yokozawa, SH

=== Minutes ===
 * Recent developments and possible issues of LVK calibration - S. Haino [[attachment:CAL-170731.pdf|slides]]
   * The localization error is estimated only with the amplitude bias not including phase bias nor time delay - answering to Tomaru-san's question
   * The preliminary results show that amplitude can also affect on the bias of localization - Kanda-san's comment
 * bKAGRA phase-1 calibration - [[http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7022|T. Yamamoto]]
   * Tomaru-san, Kanda-san and others asked how do we calibrate the time delay and how much the requirements
   * Yamamoto-san answered that for the digital control, the delay should be kept within 200 Hz. For the localization it is important to measure the delay accurately so that we can apply corrections.
   * We should study how to use Pcal to inject time reference signal but we have to understand how much we can make it independent from KAGRA digital and DAQ system. 
   * Yokozawa-san and Kaji-san are measuring the time delay as [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/DGS/Meeting/20170731/minute|DGS works]]
   * Yokozawa-san wants to compare between two or more independent GPS system. We need estimate the allowed GPS accuracy and measurement limitations
   * SH asked to Yokozawa-san to be responsible of time delay measurement in CAL group. He will discuss with people and decide later.
 * Analog circuit TF measurements and Hardware injection wave forms - T. Yokozawa  [[attachment:cal_yokozawa_170731.pdf|pdf]]
   * What is the reason of disagreement between measurements and model ? - There is a circuit to prevent oscillations but this was not modeled by zero-pole functions
   * Yokozawa-san wants to choose one waveform from each model (Taylor, IMR, EOB, ...). The choice of model is important for the physics analysis but in the view point of calibration the response of the detector is more important.
   * Yamamoto-san asked about the individual difference of TF measurements. It looks like there is a small discrepancy from the model but the individual difference is smaller.
 * Current status of Pcal development - [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7023|Y. Inoue]]
   * Tomaru-san pointed out that we should make a measurement of mode frequencies particularly in high frequency - this is not only for the mechanical stage but also the optical table and optical setups.
   * WSK (KAGRA Working Standard) is now shipped back from LHO after calibrated there. Yuki will make some measurements soon and we have to decide if we should make a modification and ship WSK back to LHO or not.
 * Development of Pcal Tx module - B.H. Hsieh [[attachment:20170731 Calibration meeting.compressed.pdf|slides]]
   * Kanda-san asked about the non-linearity of beam width VS distance. Binhua didn't take account of the measurement error so he has to take account and try a linear fitting.
 * Development and data analysis of Tcam - T. Shishido [[attachment:17'7.31_CAL MT.compressed.pdf|slides]]
   * Shishido-san wants to go to Kamioka for the installation of Tcam at X-end in mid.August when Tomaru-san will go there for CRY works. We will arrange detailed schedule.
 * AOB
   * For F2F meeting we will have presentations from Yamamoto-san, Inoue-san (15 min each) and we can use another 15 min slot divided by Binhua and Shishido-san.
   * We will have a Kick-off meeting in mid. September.