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OMC Closing Review (2022/11/18)
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 * [[ https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=14515 | OMC (Aso, NAOJ)]]
  * Higher mode rejection -> OK with good mode matching. -> will be checked after pumping.
  * New optical board to remove additional structure for resonance dumping.
  * New high-quality mirror. -> 97% T_FP.
  * Replacement of the broken  PD
  * 800 Hz resonance still remains. -> unstable lock in air. Pumping down OMC are will mitigate this resonance.
   * FP_tra estimation in air ~ 0.89 derived by subtracting HOMs power sum from the total power.
  * OMC alignment. OSTM should not be moved by pico to avoid trouble.
  * Dark noise: same btw both PDs.
  * OFI performance check to investigate mysterious power loss (60% !!). -> Good enough! No problem.

  * PD protector: Fast beam shutter(we don't have) or PZT offset to unlock the OMC. -> Urgent issue. 50mW/one PD is acceptable. 

  * Update plan to improve PD circuit for the in-air lock?
  * Notch filter cannot help to avoid resonance -> 800Hz is in the obs band!! Another circuit for the in-air work?
  * Why DC-PD was broken? -> It was damaged during removing the glass window. A high-quality can opener is necessary. A can opener of Thorlabs that has a shaper edge.
  * Quantum Efficiency of PD ~ 9? %. No actual measurement. Uncertainty is large. Measure the QE of a spare PD?
  * The calibration factor is included in MEDM.


 * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=14522 | OMMT1, OMMT2, OSTM Suspension (Takahashi, NAOJ)]]
  * Transfer Function
   * OSTM has a different TF(LPY) compared with OMMT1/2 because it has a thinner TM.
   * OSEM output values vary with each other. Coupling force variation. -> LPY coupling will be generated. Maybe acceptable because we don't use them for control.
  * Space btw magnets and plates
   * Took photos. All gaps are OK.  
  * Pico motion
 
  * TF of H1~4 phases are OK? Actuation signs (directions) are managed well? -> OSTM has different of magnets S-N direction after magnet repair.
   * Positive -> push? Should be confirmed.
   * Push -> OSEM voltage should be negative.

 * [[ https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=14523 | Installation Acceptance Document for modified sub-optics in the OMM and OMC chambers (Akutstu, NAOJ) ]]
  * [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=22934 | klog#22934 ]]
  * [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=22942 | klog#22942 ]]

  * Dumper 1 cannot kill the beam because it was shielded by wiring. No time to make a proper dumper for it. It could be between O4ab.
   * The cable cannot be removed!! A solution dose exist?? A black plate or a mirror can help??

 * OMMT2T optical setting for sensing OMMT1/SR2 motion separately (Ushiba, Akutsu, Miyoki, Sato, Takahashi, Yokozawa)
  * [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=22604 | klog#22604 ]]
  * [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=22611 | klog#22611 ]]
  * [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=22844 | klog#22844 ]]
  * [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=22848 | klog#22848 ]]
  * [[ https://klog.icrr.u-tokyo.ac.jp/osl/?r=22946 | klog#22946 ]]
  * Final alignment and Iris removal.
  * Reliable cover using aluminum foils.

 * Vacuum Issues
  * Clamp preparation -> OK, f300 -> metal, f800 -> elastomer,
  * TMP/IP alignment [[attachment:OMC-OMMT-TMIPunit.pdf]]
  * [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=22948 | Trouble in a -Y side Hatch]]
  * Opened viewports confirmation
  * Cleaning inside
  * Leak in GV_srm-OMM again??
   * Loosen the tierod bolts to free the GV motion to the OMM side.
   * Close GV btw BS-IXYC for the emergency.
   * Retighten bolts of the support of the duct near the GV_IYA.
  * Slow pumping as IFI-IMMT/IMC -> Suspension Monitoring(Takahashi-san + alpha)