ISC Meeting on 2017/9/25 14:20 - 15:00
Participants: Enomoto, Koji Nagano, Kokeyama, Somiya, Michimura, Koji Arai
Next meeting
2017/10/23 14:00 - 15:00
Agenda
bKAGRA sensitivity update [Komori] JGW-T1707038
- basically approved at EO on Sept 20
- bKAGRA Phase 1 [Michimura]
initial alignment work starts on Oct 10; see MIF Commissioning page
- no AS optics for Phase 1, instead use reflection REFL beam from PRM
- we have to prepare REFL optics
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
SRM reflectivity for early phase of bKAGRA [Enomoto] JGW-G1707078
- 50% reflectivity is better than default (85%) when input power is below ~30 W
- A/Is
- LSC and ASC check
- excess noise at low frequency
- schedule, budget, manpower
- 2inch SRM quality
- check how bad is PRFPMI with 85% misaligned or RSE with lossy SRC
- IMMT1 and IMMT2 transmission [Michimura, Takeda]
- IMMT2 transmission optics are too much squeezed
- IR/green steering mirrors [Michimura]
- will arrive at Mozumi on Sept 6
- pedestals, mirror mounts
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]
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
- 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
- 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] (JGW-T1503453)
Summarized in the paper JGW-P1707051
- waiting for Type-A seismic transfer function update [Okutomi]
- 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.