N. Sato, Yano, Akutsu

Summary

The IMMT2 shield has been re-installed (before: Fig. 1 / after: Fig. 2).

Details

When the high power beam dump will be installed in the IFI chamber, it would be hard to access IMMT2 HR, so we determined to firstly install the shield, which had been detached since 1.5 years ago (15773). This time, the heads of the fixing screws were of solblack.

After our work, we found that the IMMT2 oplev moved much in pitch, and PR2 trans QPDs showed also moving in pitch. We are not sure why this kind of plastic behavior happend. According to the IMMT2 oplev, the pitching was like a trend lasting about two hours after we stopped our work (Figs. 3 and 4).

Once we called the ALIGNED state to the IMMT2 suspension, then fortunately it came back to the original nice position within its actuator range. Then, we called LOCK_ACQUISITION and the alignment successfully got frozen at this nice alignment.