ISC Meeting on 2017/11/20 14:00 - 15:00
Participants: Yutaro Enomoto, Koji Arai, Koji Nagano, Eiichi Hirose, Kentaro Somiya, Yoichi Aso, Hiro Yamamoto
eZuce meeting: "KAGRA ISC Meeting" in the KEK community.
Next meeting
2018/1/15 14:00 - 15:00 ??
Minutes
- SRM reflectivity
Reflectivity is decided to be 70% +/- 5% JGW-G1707078
- Vendor is also decided
- Continue to seek for reducing RoC error
- 2-inch mirror holder for the metal mass will be black coated, to be bought this JFY
- OMC PD
- aLIGO uses 93% QE PD (without window) in O1, 98% QE PD in O2
- KAGRA will use 93% QE PD for now, and 98% one in future
Agenda
KAGRA configuration for early phase of bKAGRA JGW-T1707334
- SRM reflectivity
- Approved to go for metal mass SRM. Budget within this JFY
- Item to be discussed:
- how much SRM reflectivity
- also, ASC check
- mirror company
loss function estimate [Hirose] JGW-T1707296
- black coating for metal mass
- how much SRM reflectivity
- ETM swap
spare ETM quality [Hirose] JGW-T1707281
- timing depends on final ETMX arrival
- SRM reflectivity
- bKAGRA Phase 1 [Michimura]
- no AS optics for Phase 1, instead use reflection REFL beam from PRM
- we have to prepare REFL optics
- height of the beam from PR/BS breadboard will be 380 mm instead of 400 mm?
- experiments for Phase 1 paper
bKAGRA Phase 2 schedule [Michimura] JGW-T1707079
- meeting with SEO on Sept 6
- Goal: 1 hour lock of cryogenic RSE with RF readout, probably with ASC, no sensitivity goal
- input laser power not decided
- when to swap ETM, SRM reflectivity, vacuum
- schedule adjustment between AS WFS and OMC test necessary
- IMMT1 and IMMT2 transmission [Michimura, Takeda]
- IMMT2 transmission optics are too much squeezed
- IR/green steering mirrors [Michimura]
- mirrors arrived, mirror mounts and picomotor driver ordered, pedestals by Akutsu, vacuum cables by Aso
- DC QPD holder [Michimura]
beam height should be 4inch to use similar mount, with small modification of spacer (instead of 3inch in JGW-D1402607)
- RF PD, RF QPD boxes are designed for 4inch beam height
- stages are not needed for ISC DC QPD
design new ones; they can be very simple [-> Michimura?]
- calibration can be done in different ways
- put strain relief and anchors for cables to protect QPD board
- OMC and OFI [Somiya]
- look for OFI with larger aperture [Somiya]
- DC PD and DC QPD [Michimura]
- DC PD not available. Look for product with similar specs
- DC QPD available from RS
In-vacuum RF PD and RF QPD
- we need them within 1 year, considering OMC REFL and AS RF
In-vac beam-dumps
- required spec?
PSL EOM Layout re-consideration [Enomoto] (JGW-T1706748)
- Delay-line length decided to be 2.66 m (instead of 8.88 m)
- Modulation phase between f1 AM and PM is always aligned (we need this to be aligned)
Modulation index needed at each EOM is less than measured maximum index by Uehera (JGW-T1605611)
Optickle simulation by Kohei Yamamoto JGW-G1707309
- simulation on imperfections (MZ arm asymmetry, MZ lock, EOM phase difference control etc.)
- start with hand calculation, simple setups, and then to full IFO simulation
- Optickle model basically made, and checked with hand calculations
- calculations for requirements on delay line lock displacement noise, parallel EOM MZ lock displacement noise, EOM modulation phase difference, EOM imbalance on-going
- A/I: check phase noise calculations, requirements for f1 AM-PM mixed case [Kohei Yamamoto]
- Requirement on carrier power loss?
- Comment from Stefan Ballmer
- Similar calculation was done in LIGO in the past. Displacement noise requirement for MZ was tough (~1e-14 m/rtHz).
- Any in-air interferometer suffer from jitter and frequency noise which cannot be suppressed.
- Actuator noise modeling [Michimura,Miyamoto]
Summarized in the paper JGW-P1707051
- Needs to implement frequency noise, but FSS modeling with ALS is complicated [student!]
Discuss mirror vibration from heat link
- Meeting on July 14 [Yamada, Miyamoto, Ushiba, Michimura]
See this page for other agendas.