Differences between revisions 27 and 28
⇤ ← Revision 27 as of 2022-11-18 16:30:58 →
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← Revision 28 as of 2022-11-19 09:32:06 → ⇥
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Editor: miyoki
Comment:
Deletions are marked like this. Additions are marked like this.
Line 60: Line 60:
   * 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.

OMC Closing Review (2022/11/18)

  • 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.

  • 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.

  • Installation Acceptance Document for modified sub-optics in the OMM and OMC chambers (Akutstu, NAOJ)

    • klog#22934

    • 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)
  • Vacuum Issues

    • Clamp preparation -> OK, f300 -> metal, f800 -> elastomer,

    • TMP/IP alignment OMC-OMMT-TMIPunit.pdf

    • 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)

KAGRA/IFOIntegration2022/2022OMCClosing (last edited 2022-11-19 09:32:06 by miyoki)