Participants: Yamamoto, Miyakawa, Nakano, Somiya, Akutsu, Ueda, Takahashi, Sekiguchi, Michimura, Aso
Current Status
- Ask Izumi-kun, the status of green lock at LIGO.
- Back up plan for lock acquisition (in case green does not fly) is necessary.
- - Transmission power offset lock - Digital Interferometry ?
- KAGRA CDS for Interferometer Control will be developed at Kamioka.
- - Will allow remote access to the system for remote development - Improve the CLIO CDS to be a prototype of KAGRA CDS
- Installation planning has to be started immediately
- - How to precisely locate and align mirrors ? - List up necessary vacuum feedthrough - Prepae rack wiring diagrams
- Vacuum Enclosure
- - Find better companies in Japan. Work with VIS.
- Beam Handling in Vacuum
- - Building an integrated CAD model of the vacuum chamber and suspensions to properly arrange beam damps and so on.
- OMC
- - Better calculation of HOMs with realistic phase maps of the mirrors.
Beam Shutter Development (by Ueda)
- A fast beam shutter prototype with HDD motor was made.
- 1.5msec to move 1.5mm. 1.8msec for 5mm.
- E2E simulation for deposited power on PDs when lock is lost (about 3W at AS)
- PD damage threshold ~ 100mJ ?
- Open questions:
- - Where to put the shutter. Before or after the OMC ? - Scattered light noise by the shutter blade. - Black coating on the blade ?
Suspension modeling with active damping (By Sekiguchi, Nakano)
- A pre-isolator model with active damping using LVDT and GEOPhone was made
- Calculations were also done for full Type-A and Type-B cases.
- Sensor noise is a serious problem in all the cases.
Requirements for vibration of in-air optics
- Beam jitter and scattered light noise should be considered.
- For actual purchase of optics mounts, we should select the shortest possibe ones.
Action Items
- Get more information on the green lock status in LIGO (Aso)
- Installation planning (Aso)
- Find a good company to make vacuum PD enclosures (Akutsu)
- Continue the beam shutter study (Ueda)
- Continue the active damping study (Sekiguchi, Nakano)
- Vibration level requirements for in-air optics (Nakano)
- Ask Telada-san to make a list of small optical components to buy (Aso)