ISC Meeting on 2017/4/10 14:00 - 15:00

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Next meeting

2017/4/24 14:00 - 15:00

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Agenda

• Actuator noise modeling [Michimura,Miyamoto] (JGW-G1706333)

  • now included quantum noise and magnetic noise (JGW-T1503453)

    • do we use ALS DIFF or IR DARM quantum noise for ETMs?

  • actuator design for cryogenic payload (JGW-G1605938)

    • magnets for Marionette too small? (ActuatorDesign wiki)

      • use BF also for locking

  • magnetic noise JGW-T1504459 [Shimoda]

    • got measured spectrum from Tanaka

  • Recommendation from ISC: Bigger magnets for Marionette of cryopayload [Aso->Tomaru, Michimura->Miyamoto]

    • range should be ok, but to be more safe
    • CRYp people are thinking of using bigger magnets (x60 higher moment?) [Miyamoto]
    • bobbins for TM,IM are made of "Shapal" (machinable ceramics) those for Marionette are made of Aluminum [Tomaru]
  • include local damping servo of Type-A (room temperature part)

  • is actuator efficiency measured at cryogenic temperature? [Michimura-> ask Miyamoto]

    • No [Miyamoto]
  • try including ALS sensing noise (shot noise, frequency noise etc.) to check actuator range [Michimura]
  • confirm with VIS people if velocity requirement from lock acquisition is achievable or not
• RF Doubler requirement [Michimura]

  • aLIGO uses RF Doubler (and DivideByTwo) for ALS, but no need for KAGRA

  • aLIGO uses Harmonics Generator for generating f1, f2, 2*f1, 2*f2, but for KAGRA, we will use two oscillator for f1 and f2 and two Doubler for 2*f1 and 2*f2 (we might use Harmonics Generator in the future; see ISC Meeting Minutes 20161212)

  • aLIGO RF Doubler spec (LIGO-D1002178, LIGO-T1000480)

    • Wenzel 600-22672
    • 79.4 ± 1.2 MHz (input); 158.8 ± 2.4 MHz (output)
    • Noise floor -170 dBc/Hz (10 kHz offset)

    • Harmonics < -25 dBc; Sub-Harmonics < -40 dBc

  • aLIGO Harmonics Generator spec

• OFI and OMC status (JGW-T1706334) [Somiya]

  • new AS optics layout: SRM -> OMMT1 -> OMMT2 -> OFI -> STM -> OMC

  • look for OFI with larger aperture [Somiya]
  • OMC should be actuated also
  • prototype OMC for practice of gluing, locking

• What can we do now?
  • RF PD/QPD characterization
  • electronics and cabling diagram
  • RT modeling, MEDM screens, guardian scripts

  • better modeling (Optickle, Finesse, FFT, NoiseBudget, etc.) for ALS and intermediate configurations

  • RF generation scheme, RF AM generation scheme
  • AS optics (OMC, OFI, OMMT)
  • initial alignment planning
  • in-vacuum optics/electronics design
• 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 faint transmitted beam after ETM installation (~0.25uW)

      • use green?
        • BS transmission for green is S:99.40% P:97.85% at 45 deg
        • 100 mW green beam from PR gives ~0.12 mW at ETMY transmission

    • 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 tanks/ducts are installed considering ETM wedge effect

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

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

      • as for NAB: install if possible, but maybe without suspension
      • as for WAB: try WAB with suspension at EXC, maybe no installaton at EYC
        • how to peel off the first contact?
        • we cannot see the beam on ETM with IR cards with WAB
      • first priority is cryopayloads and evacuation/cool-down

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

    • CAL report (JGW-G1605737)

    • wide angle baffle modification is needed to see the ETM edge
  • how to extract AS beam should be fixed by MIF

    • extract SR2 reflected beam at SR3 chamber (decided at the meeting on Sept 13)

    • Layout around SRs (JGW-T1605967)

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

  • TMS possible without ITM? [Akutsu->Michimura]

    • check q-parameter at TMS witouht ITM

• 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

  • Quad IQ Demodulator LSC to ASC
    

    • 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 JGW-D1504460

    • we will omit RF monitor for now, and add them later
    • front/rear panels, RF amps, 8-way splitters, couplers, cables and connectors at Mozumi office loft
  • RF Frequency Doubler

    • what's the frequency? [Kamiizumi->Michimura]

      • thought used for 2*f1,2*f2, but aLIGO uses them for ALS

  • Requested Universal Whitening Filter with DC Power to AEL (JGW-T1605839)

    • see DCQPDDriverList (see, also, DCQPDList)

    • need to coordinate with subgroups (MIF, IOO, AOS, VIS, CRY)
• RF PDs and RF QPDs
  • RF PD / RF QPD noise and transimpedance characterization
    • we need permanent test bench
  • 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)

  • vacuum optics to extract beams for each port (except for REFL and AS DC) and related beam shutters will also be MIF task
  • all the optical tables purchased and delivered to tunnel

• 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?

      • ask LIGO people how they are fixing the cables

        • no special vibration / heat treatment [from Kawabe]
    • 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

    • local oscillator phase noise (calculation method)

      • discuss with Aso and redo calculation

• 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
  • IMMT resonant frequencies: pitch ~1.8 Hz, yaw ~1.5 Hz

  • this gives 50/sqrt(2) mm * (1.4e-3 N/A * 4) * 4 magnets * 1/80 A/V / 9.6e-4 kg*m²　 / (2*pi*1.8 Hz)² = 8e-5 rad/V efficiency in pitch

  • is this enough?
    • IMC mirror (Type-C + stack) drift in yaw was less than 1 mrad/month, pitch was much less [Nakano]
    • iKAGRA ETM (Type-C w/o stack) drift was ???
• 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"

  • in case of KAGRA, we don't need Frequency Doubler or Frequency Divide By Two for ALS

    • is this true?
• 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]
• 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 is TMS-like plate spring and single pendulum [Somiya]

• Task list update (TaskList) [Michimura]