MIR Meeting on 2023/07/05 15:00 - 16:00
Participants: KYamamoto, June-Gyu, Marc, Sungho, Aso, Matteo
Next meeting
2023 Aug 2nd, 15:00 - 16:00
Minutes
Paper on coating (Mori, Nakayama, KYamamoto): Ti doped (LIGO) and undoped (KAGRA) SiO2-Tantala stacks
- coating thermal noise seems higher than expected value
- internal review by coauthors being done at the moment
- will be circulated to MIR subgroup in the next weeks
- Planned presentation of the measurements contained in the paper at the next LVK
- Measurement of Q-value for KAGRA sapphire mirrors
- CARM-DARM as readout sensors, magnets as actuators
- T= 80K for ETMX and T=250K for all the others
- all Q value are between 1e4 to 1e5, seems low compared to expected value of 1e8
- investigation of the reason of low Q ongoing, dissipation source is not clear
- offline test on spare ETMs could be done to investigate the source of dissipation (Aso)
- report on polishing of new ITMs by Aso
- Shaping, lateral flats and barrel done by ARD
- pre-polishing and wedge will be done by Okamoto Optics (test polishing done successfully)
- lead time of pre-polishing is largely increased due to necessity to avoid subsurface damage
- no issue due to delay of pre-polishing since LMA is busy until the end of O4 on A+ coating
- final polishing planned to start in march 2024 and last 12 months
- paper plan
- commissioning paper on birefringence was merged with O3GK paper
- birefr. exp setup + birefr. to internal stress paper under review
idea to merge simulation paper (by Haoyu) and methodology paper (by Aso) -> potentially almost ready (iPWT: Haoyu-Aso)
- idea to have a paper on Aztec crystal characterization (iPWT: Marc-June Gyu)
- idea to have a paper on eterodine AA with birefringence (iPWT: Marc-Haoyu)
- report on spectrophotometry measurement by Marc
- calibration is ongoing, spectral shape as expected
- report on liquid crystals by Marc
Agenda
- Coating and Q-measurement update from KYamamoto
- Polishing update from Aso
- MIR related paper plan discussion