Kokeyama, Satou, Akutsu

Cont'd from 15599
Today we continued the inspection of the inside of IFI and IMM chambers; maybe we finished mostly.

• Yesterday we found unexpected weak deformed ghost beam near the IMMT2 transmission beams (Fig 1), and we checked it again and understood that it was just a ghost beam created at the IMMT2 suspension structure pillar.
• Finally we detached the steering mirror behind the IMMT2 and replaced with a beam dump for S which was left in the IMM chamber without any reason(?). The ghost beam height was in-between 210-220 mm from the top surface of the breadboard in the IFI chamber, but due to (1) the beams were thick and (2) the beams go slightly higher than the beam dump's glass, so we might need to redesign specially for this location
• Instead of taking efforts to extract the IMMT2 trans beams, it would be better to replace the 1inch mirror for oplev beam folding to 2inch.
• Maybe due to the incident beam, the side of the LED lantern was metlted! Be careful... (Fig. 2)