ISC Meeting on 2016/10/17 14:00 - 15:00

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2016/11/14 14:00 - 15:00 ??

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Agenda

• MIR update [Hirose]
  • coated PRM reflectivity acceptable?
    • required spec was 10 +0.1 % / -0 %, but measured value was 10.35 %
• bKAGRA Phase 1 optical configuration study [Michimura]

  • summary: JGW-T1605595

  • ASC [Enomoto]

    • noise study by NoiseBudget [Enomoto]

      • Enomoto volunteered to do ASC NoiseBudget; meeting on Sept 27

        • trouble on number of licenses and library links, but finally able to run example model
    • effect on WFS from RF HOMs [who?]
  • check if reference spheres for PR mirrors are available at Caltech [Hirose]
    • 9.0m (CC), 11.5m (CC), 6.5m (CC), 5.0m (CC), 34m (CX), 36m (CX) were available
    • PR2/SR2 is -3.0764m/-2.9872m and PR3/SR3 is 24.9165m. Maybe 5.0m TS can be used for PR2/SR2.
    • what about PR3/SR3, PRM/SRM?
  • check if IMC length stability and others are compatible with 3-km PRMI [Michimura]

• bKAGRA Phase 1 initial alignment / commissioning plan [Michimura]: JGW-T1605595

  • procedure summarized in JGW-T1605692

    • presented at Chief Meeting on Sept 26

    • TMS BRT alignment could be tough because of dim transmitted beam after ETM installation

      • use green?

    • check optical layout [Michimura->Aso]

  • check if ETM transmitted beam can go through when ETM is not installed [Michimura]

    • ETM transmitted beam can reach EXT/EYT when no wedge (5.6 mm shifted from the center of EXT/EYT)
    • EXT/EYT is installed considering ETM wedge effect

  • wide/narrow angle baffles for Phase 1? [Akutsu]

    • talk with Uchiyama & Saito on Sept 27-28?

  • discussion on camera to see ETM HR surface started [Akutsu, Inoue, Kokeyama]

    • start with a plan to use viewport at EXA/EYA
    • baffle design have to be modified to see the edge of ETM
  • how to extract AS beam should be fixed by MIF

    • extract SR2 reflected beam at SR3 chamber

  • IMMT1-IMMT2 beam collimation plan not yet [MIF]
  • green alignment plan not yet [MIF]

• bKAGRA Phase 1 analog electronics (Analog Electronics for ISC) [Michimura]

  • Quad IQ Demodulator heat-up issue
    • 1st stage amp is heating up

    • we have to decide if we need 1st stage amp or not

  • remake of Quad IQ Demodulator LSC to ASC [Michimura->Niigata students?; by 2016.10]

    • MIF will take care instead of AEL
    • mass production will be taken care by AEL

    • 4-way splitter (Mini-Circuits ZFSC-4-1-S+) arrived at Kamioka -> Mozumi office loft

  • RF Distribution Amplifier [Michimura->Niigata students?; by 2016.10]

    • we will omit RF monitor for now, and add them later

    • Nakano found front/rear panels -> Mozumi office loft

    • ordered RF amp (Wenzel LNBA-11-23-CK-100-15) -> not yet arrived (by the end of Sept?)

    • 8-way splitter (Mini-Circuits ZCSC-8-1+), coupler (Mini-Circuits ZX30-20-4) arrived at Kamioka -> Mozumi office loft

    • cables and connectors to assemble one chassis by hand arrived at Kamioka -> Kokeyama's desk

    • basically copy of LIGO-D1000124, but we will omit Interface for the first stage

    • asked AEL to make RF amplifier interface board (which is also used for Frequency Doubler) [Michimura]

  • RF Patch Panel modification [Michimura->Niigata students?]

    • one by one by hand is tough; outsource?
  • Electronics request meeting with Miyakawa/Kamiizumi on Aug 24
    • photos of the assembled chassis are helpful for AEL

      • does anyone have a photo of Frequeny Doubler? LIGO-D1002178

        • photos arrived JGW-T1605492

• RF PDs and RF QPDs
  • RF PD / RF QPD noise and transimpedance characterization [NiigataU?]
    • need to check RF QPDs for IMC WFS, by the end of Oct 2016
    • IR LED is at Kamioka, no network analyzer at Kamioka (one at Toyama U and the other at Kashiwa)
  • RF PD modification [who?]
    • fix DC path
    • solve single supply issue (RF PDs easily break when accidentally supplied with single)
    • fix plugs so that Dsub 9pin cable fixes better

• Output optical tables [Michimura] (OutputTables wiki)

  • Kawamura suggested to move this task from IOO to MIF

  • vacuum optics to extract beams for each port (except for REFL and AS DC) and related beam shutters will also be MIF task
  • MIF and IOO agreed, SEO agreed, next step is budget migration
• RF generation scheme [Michimura]
  • f1 = 3/8*f2, f3 = 10/8*f2
  • we need 2*f1, 2*f2, f3-f1, f3-f2 as well
  • use harmonics generator (x2, x3, x6, x8, x10, x16 for f2/8 = 5.62698725 MHz (FSR for IMC))
    • seeking for vendors

  • MIF and IOO agreed to use 13.78 MHz　(~= f2/8*2.45) for IMC sideband (JGW-T1605493)

  • MIF agreed to use 32 MHz and 33 MHz for ALS sidebands JGW-T1605626

  • may be IMC sideband (and ALS sidebands) should also needs to be phase locked with f1/f2/f3 to avoid "whistling noise"

• Arm Length Stabilization plan (JGW-T1605353)

  • NoiseBudget [Kambara]

    • results agreed with Tatsumi Simulink model
    • include fiber noise (fiber setup is different from Tatsumi model)
      • fiber length? how to do the wiring?
    • include phase noise from mirror vibration for IR beat setup (it is one of the limiting noise source for aLIGO)
    • schedule and plan for the procurement of circuits should be fixed soon
      • keep in touch with AEL group

• Requirement on actuator range for IMMT [Ohishi]
  • magnet size: 2 mm dia, 5 mm long
  • coil turns: 39?
  • this gives 4 times larger efficiency than the IMC coil efficiency

  • this gives 50 mm * (1.4e-3 N/A * 4) * 4 magnets * 1/80 A/V / 9.6e-4 kg*m^{2 / (2*pi*3 Hz)}2 = 4.1e-5 rad/V efficiency

  • is this enough?
• bKAGRA optical layout around PRC
  • POY clipping issue will be solved by modifying PR3 optical bench suspension [Shoda]
  • we need layout CAD for POY pickoff mirror, POP pickoff mirror to design baffles
    • budget for baffles around POY and POP were shifted to next FY [SEO]
• Requirement for the noise of watchdogs for coil drivers [Aso]

  • recent result show dR < 1e-7 Ohm/rtHz, so it may meet the requirement

  • slow (~20 min) drift at dR ~ 5e-4 Ohm -> this should be negligible

• viewport quality for GV between SRM and OMMT [Akutsu]
  • aLIGO case: SRM-OFI-viewport, KAGRA case: SRM-viewport-OMMT-OFI
  • aLIGO viewport is always closed

  • if we need super quality viewport, we have to decide soon

• BS baffle could make contract defect? (LIGO-T1000090)

  • ask Akutsu and Hiro
  • BS has 370 mm dia and beam at BS is 2*36 mm dia. So, it should be in principle OK. But recoil mass aperture should be considered.
• bKAGRA ISC cabling [Michimura/Doi]
  • announced to IOO mailing list
  • need to update the cabling diagram
• Mirror absorption measurement status [Hirose]
• Output optics status [Somiya]

  • suspensions for OMMT1/2 is same as IMMT1/2 (driver list for now: JGW-L1605334)

  • we have to make vacuum compatible PD/QPD for OMC by 2018.3
  • beam shutter: prototype done, AR coating and driver circuit design not yet

  • OMC suspension requirement cross check [Somiya]

  • OFI, OMMT, OMC meeting on 2016.9.14

    • design suspended table similar to TMS?

• Magnetic noise, actuator noise calculation for cryogenic payload [Michimura]

  • actuator noise calculation on going by Miyamoto & Okutomi

• Task list update (TaskList) [Michimura]