ISC Meeting on 2016/8/8 14:00 - 15:00
eZuce: http://srn.ezuce.com/joinSRN?meeting=MtM8Ma2B2eDuDv9s9sDs9t
Participants: Enomoto, Kokeyama, Nagano, Kambara, Arai, Akutsu
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?
- we found mistake in the HOM structure check code
- 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
- use 2017.10-11 to test PR-ETMY and ETMY cooling
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?
- Quad IQ Demodulator heat-up issue
- 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, ask Takahashi-san to add drivers to his list: JGW-L1605193
- 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
2016/8/8 14:00 - 15:00