Participants : M. Eisenmann, M. Otsuka, S. Singh, K. Somiya, K. Yamamoto

Agenda :

* New ITMs polishing update (M. Eisenmann)

• Preparation of bidding for next step polishing on-going

• Birefringence measurement update (S. Singh)
  • Analysis seems good; plan for 2D measurements + on-site measurement
• Q measurement and simulation update (K. Yamamoto)
  • Yamada-san and Rishabh busy... K. Yamamoto can give updates in the meantime
  • dummy mirror suspension on-going from next month
• Coating and U. Toyama activities (K. Yamamoto)
  • Coating mechanical loss at cryogenic temperature paper was accepted

  • McGhee (Glasgow) visit from end of March to July to measure amorphous Silicon coating mechanical loss at 100K

  • In future plan to exchange samples to compare GENS and nodal support techniques
  • Yu Sato will finish Master thesis about PI in Feb 2025
  • It seems that mode shape depends on a-axis direction
• PI simulation (M. Otsuka)
  • optical simulations on-going with goal of estimating modal content of coupled cavity
• New AZTEC samples characterization + spectroscopy (M. Eisenmann)
  • Could estimate impact of impurities on 1064nm absorption and compare it with PCI absorption for few samples
  • Plan to do spectroscopy measurements with s-polarized light
  • Plan to have new holder to test new AZTEC samples
• Possible crystalline materials conference? (M. Eisenmann)
  • Opening of Kakenhi for conference support
  • There are ASPIRE and bilateral calls aswell (K. Somiya)
  • There are interest but should further discuss to avoid competing with each others
• Discussion
  • Thermal noise derived from new coating mechanical loss should become KAGRA official value
  • This new value was used by Komori-san in the 10 years sensitivity simulation