ISC Meeting on 2016/8/22 14:00 - 15:00

Participants: Michimura, Aso, Enomoto, Arai, Kambara, Moriwaki, Akutsu, Hirose, (Kawamura)

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2016/9/5 14:00 - 15:00

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Minutes

• bKAGRA Phase 1 TMS/mode measurement [Enomoto]
  • by measuring the beam radius at ETM, g-factor can be measured within precision of ~0.09; not enough

  • more precise measurement can be done using transfer function measurement with injected sidebands trough IMC (see LIGO-G080467)

    • consider using this technique

  • it takes only few minutes to adjust PR2-3 length (even in vacuum) [Aso] -> confirm with Shoda again [Michimura]

• bKAGRA Phase 1 analog electronics [Michimura]
  • MIF agreed on recent electronics request to AEL
• Output Optics Table [Michimura]
  • MIF group agreed to move this task from IOO to MIF
    • needs agreement from IOO group and then from SEO
  • safety issue on 2 W beam exposure in air should be discussed
• RF generation scheme [Michimura]

  • IMC sideband frequency (JGW-T1605493)

    • MIF agreed to use f2/8*2.45 = 13.78 MHz for IMC sideband
    • needs agreement from IOO group also
  • may be IMC sideband (and ALS sidebands) should also needs to be phase locked with f1/f2/f3 to avoid "whistling noise"
    • it could be easily done with N5181A, but maybe not with VCXO(OCXO?) to be used in the future

• NoiseBudget for green lock [Kambara]

  • fiber noise was added (see LIGO-T0900376)

  • Prometheus laser noise was updated to use spec from Coherent

    • real SHG noise is not available yet -> ask Kawabe/Izumi [Kambara]

• Updates from MIR group [Hirose]
  • availability on reference spheres for PR mirrors will be checked this week at Caltech
  • AR aperture is 204 mm dia for sapphire mirror
    • this size is tolerable considering 35.3 mm beam radius on ITM/ETM and 2.7 sigma (1 ppm loss)

    • aperture of recoil mass should also be checked [Michiura->Tomaru]

Agenda

• bKAGRA Phase 1 optical configuration study [Michimura]

  • HOM structure / ASC check [Enomoto] (JGW-T1605362)

    • decided to move PR2/3 by 1.20 cm -> confirm with Shoda again [Michimura]

      • Shoda said 1.20 cm is OK

      • Now the question is how long does it take to adjust it again -> asking Shoda

    • even if we move by 1.20 cm, PRMI is still unstable in worst RoC error case
    • effect on WFS from RF HOMs should be [who?]
    • feedback topology and noise study should be done [Enomoto?]
    • how to measure the g-factor? PRMI cavity scan possible?
    • need to make beam profiling plan [Enomoto]
  • check if reference spheres for PR mirrors are available at Caltech [Hirose]
  • check if IMC length stability and others are compatible with 3-km PRMI [Michimura]

• bKAGRA Phase 1 initial alignment / commissioning plan [Michimura]: JGW-T1605274

  • beam profiling plan should be compatible with vacuum plan; MIF will lead the planning
    • not only PR2-PR3 but also IMMT1-IMMT2
  • how to extract AS beam should be fixed by MIF
  • CRYp agreed on installing ETMY earlier by two months (ETMY CRYp: 2017.8-9, ETMX CRYp: 2017.12-2018.1)
    • use 2017.10-11 to test PR-ETMY and ETMY cooling

      • negotiate with CRYp to fix ETMY cooling schedule

• 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 istead 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

    • where did front/rear panels go? -> look for them on Aug 24 [Nakano]

    • ordered RF amp (Wenzel LNBA-11-23-CK-100-15)

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

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

    • ask LIGO people for necessity of RF monitor [Michimura]
      • RF monitor was used in aLIGO for noise hunting and IFO health check (input from Izumi)

    • we have to request AEL to make interface board

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

    • one by one by hand is tough; outsource?
  • Requested to AEL; meeting with Miyakawa on Aug 24 [Michimura]

    • Quad IQ Demodulator LSC JGW-T1605487

    • Quad IQ Demodulator ASC JGW-T1605488

    • High Power Coil Driver JGW-T1605489

    • RF Distribution Amplifier JGW-T1605490

    • Common Mode Servo Board JGW-T1605491

    • Frequency Doubler JGW-T1605492

• Output optical tables [Michimura] (OutputTables wiki)

  • Kawamura suggested to move this task from IOO to MIF

  • Is it acceptable?
• 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

  • sideband frequency for IMC? (should be determined before EOM production; by the end of 2016.8)

    • f2/8*2.45 = 13.78 MHz for IMC anti-resonance? (JGW-T1605493)

• Arm Length Stabilization plan (JGW-T1605353)

  • NoiseBudget [Kambara]

    • results agreed with Tatsumi Simulink model
    • include fiber noise (fiber setup is different from Tatsumi model)
    • 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

• 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

    • possibility of buying baffles next FY? -> ask SEO [Aso]

    • ask SEO to hire a person dedicated for optical CAD
    • layout CAD will be prepared by each subgroup for the time being
• iKAGRA post-run calibration mystery [Aso]
  • mysterious LPF was from saturation

  • write an elog about this conclusion [Aso]

• 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]
  • need to announce to IOO,ISC mailing list; e-mailed to Doi-san for go sign
• 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]

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

  • Ask Tomaru about the parameters and actuator design, range

• Task list update (TaskList) [Michimura]