= CARM signal detection by using 2nd PD 2023/07/24 =
Participants: Komori, Aso, Miyoki, Ushiba, Uchiyama, Miyakawa, Akutsu, Dan, Oshino, Washimi, YamaT, Takahashi.R, Kanda, 

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

== Minutes ==
 * [[ https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15092 | Presentation by Komori-kun]]
  * 2/7 CARM out of loop measurement.
   * Old estimation: shotnoise should be below the unknown noise (< kHz).
   * For noise budget: If shot noise at in-loop PD1 limits, the shot noise of PD2 has no coherence with shot noise at PD1.
   * Analog excitation is necessary for injection. But MOC is connected at this point. So we need cable reconnection. SW can be introduced?
   * 
  * 3/7 RF PD
   * We have several.
   * Shunt R should be removed. Tune RF properties.
  * 5/7 Reck preparation: OK
  * 6/7 Where we should put PD2?: Wide space
  * 7/7 Schedule: Aug/21~28 (2 days)

 * Opinion:
  * How about 3rd PD for the MICH control?
   * CARM PD can be used, however, the laser power is minimized for CARM. While MICH requires more power!
   * Haoyu calculated we could obtain a better S/N signal or not -> Yes!! 10 times better than CARM Q phase signal.
   * 2nd PD can be used for this purpose?
   * 50mW can be detected by these PDs.
   * 10W is necessary.
   * Model number will increase. Can we?? Dual IQ can be added in a rack?. Quad IQ can be used for minimization? Whitening one more. 
   * Let's put 3rd PD anyway. After we will check DGS.
  * The 2nd PD will not require Dolphine?
  * MICH signal switch is supposed btw the present MICH PD and PD2? -> Maybe can be done by the digital system.
  * The mysterious shutter problem can be solved at the same time??
  * Power adjustment can be acceptable if we increase the IMC out power.
  *BNC-Dsub is available?