ISC Meeting on 2019/11/18 14:00 - 15:00

Participants: Eleonora Capocasa, Terrence Tsang, Kiwamu Izumi, Koji Arai, Tomotada Akutsu, Yoichi Aso, Takafumi Ushiba, Masayuki Nakano, Anamaria Effler, Osamu Miyakawa

Zoom meeting: https://zoom.us/j/6676627462

Next meeting

TBA

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Minutes

• FPMI ASC
  • I and Q demodulation phase optimization seems strange
    • A/I: Do it with beams on all four quadrants, drive hard and soft mode directly
  • In aLIGO case...
    • Yaw SOFT is not controlled. UGF of HARD is higher than that of SOFT.
    • SOFT loop is AC coupled, and used for damping
    • Beam position control is done very slowly with dithering ITMX/ETMX/ITMY, at 7-8 Hz.
  • What to do with MICH?
    • Theoretically, AS Q. But also look into REFL and POP if they have better signal.

    • Simulation results in JGW-T1910359, O3ASCOptickleSimulations.zip. See bLCGT-BRSE-negative-pitch-28-Aug-2019_O3SRCgouyITMasymFPMI folder for the ASC signals at all the ports.

  • Oplev loop vs global ASC loop

    • Terrence proposal JGW-G1910995

      • Sounds nice, but complicated. We also need to take into account the noise.
    • Current solution is to turn off the oplev DC loop when the global loop is on, and turn the oplev DC loop on when the lock is lost, with updated offsets. Currently, oplev damping loop have to be always on, since UGF of ASC loop is quite low. We might be able to increase the UGF by optimizing the filters, and if damping loop with SOFT mode works fine, may be we can turn the damping loop off.
• Optical table cover assembly
  • Be careful that POP table is not fixed on ground
  • Nov 26-28 might not be good.
  • A/I: Ask JVI people if they can come on Dec4-6 instead.

Agenda

• FPMI ASC

  • FPMI ASC status slides [Eleonora, Terrence, etc]

  • FPMI ASC simulation JGW-T1910359 [Michimura]

• Optical table cover assembly [Michimura]
  • Work with JVI on Nov 26-28. Preparation works on Nov 25.