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

eZuce:

Participants:

back to Meetings page

Minutes

bKAGRA Phase 1 HOM structure / ASC [Enomoto] (JGW-T1605362)
- decided to move PR2/3 by 1.20 cm -> confirm with Shoda-san again [Michimura]
- 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?]
NoiseBudget for Arm Length Stabilization [Kambara] (JGW-L1605485)
- 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 (by UToyama or AEL?) should be fixed soon
IMC sideband frequency [Michimura]
- f2/8*2.45 = 13.78 MHz plan was explained briefly
- we will decide on the next meeting

Agenda

bKAGRA Phase 1 optical configuration study [Michimura]
- HOM structure / ASC check [Enomoto] (JGW-T1605362)
  - we found mistake in the HOM structure check code
    - PR2-PR3 length re-calculation ongoing
    - we can move PR2/3 by 1.20 cm at max [Shoda,ATC]
  - Comments
    - Feedback topology. Change which mirror to feedback depending on the frequency?
    - Using DC signals for TMs may not be good from the view point of noise.
    - How to measure the precise distance between PR2-PR3?
    - How to de-couple the distance error and ROC errors?
- 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
- discussed at Extended Chief Meeting on July 4 (JGW-G1605352)
  - beam profiling plan should be compatible with vacuum plan; MIF will lead the planning
  - 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?
  - 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?]
  - outsource?
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?
Arm Length Stabilization plan (JGW-T1605353)
- ALS Meeting on July 27 (Minutes page)
- agreed that the default plan is to use Tatsumi et al. configuration and to put AUX lasers at PSL table in the clean booth
- noise study [Kambara](boot camp on August 1-5 at Hongo)
  - started with reproducing Tatsumi model (GreenLock NoiseBudget SVN)
  - Tasumi Simulink model and Kambara NoiseBudget model basically agreed (JGW-L1605485)

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]
- Doi-san said he will help.
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]

Next meeting

2016/8/22 14:00 - 15:00