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 * [[]]  * [[http://klog.icrr.u-tokyo.ac.jp/osl/?r=16126]]



Today's activities

  • Workers-1: Akutsu
    • I tried to replace the old oplev TX holders to the newer version. So I started with the one for MCi. I should have done this work together with monitoring some signals related to this oplev, but I did not and I slightly regret it. The upper part of my body can enter from the K400 flange to access near MCi to trace the oplev beams, but it is difficult to do two things at once; looking at the beam in the chamber and aligning the oplev TX outside of the chamber... Anyway, maybe the oplev beam was clipped anywhere or something wrong, maybe; the related signals (SUM, PIT, YAW) show strange beat notes; I need to check if this was NOT existing before I replaced the TX holder... I also have moved the QPD side!! by hoping something improved, but the beat note was there; before moving the QPD, I should have checked whether the beat note surely appear after my replacement of oplev TX or not. The TX and QPD (i.e. RX) are not fixed yet so please be careful.

Next plan

  • Check where the oplev beams fly!

  • Wash some screws.
  • Have VIS to check whether every combination of the coil and magnet axes is centered.
  • Check the ghost beams.
  • Consider how to separate the beam dumps from the main beam as well as install them. --> Using grid structure?? AmiAmi.

    • And revise the beam dump document. Determine if we need to replace some of KG5 glass plates with SiC ones or not... to deal with occasional illumination...
    • Where to put the dumps for GBs "N", "K", "f", and "a" (see here for the identification). -> At least, "a" can be dumped at the position well separated from the main beam.

    • How to install the dumps; maybe anyway we need to detach the K400 flange (with viewport windows) to access there.
  • How to install the beam dump around MCe... it was hard to see the MCe transmission beam even during flashing although we used P-pol.
  • Due to not calibrated actuators, it was hard to know how much counts to be input into the coils during the alignment work to flash IMC. Need to say this to VIS. Calibration!
  • Check the oplev beam spots on the mirrors! At least on MCe, the beam is just illuminating the wire break at the -X side. And adjust them.
  • Need to an encoder for HWP in the PSL room for the beam power calibration... --> Oshino-san takes care of this with Ikeda-san; see the mail on 2021 Feb 18 3:18. The script for manipulating the encoder is planned in June.

  • Check where the main beam should have gone through on the viewport window on the gate valve between MCF and IFI on the design.


  • 1 sticky mat to get the dirt off our feet.
  • A white paper that can partly pass the oplev light beam.
  • An English keyboard for the workstation at PRM.
  • Periodically bring the laser light into IMC to check the flashing.

KAGRA/Subgroups/SysInt/IMC_O4/2021-03-02 (last edited 2021-03-03 00:22:03 by TomotadaAkutsu)