Ushiba, Tomaru, Yasui, Akutsu; Follow up of 19322.

Abstract

We re-launched this work with roughly confirming whether IR beams would illuminate the center of IMMT1, 2, PR2, PRM. Next we tweaked PR2 so that the IR beam that was reflected at PR2 illuminated the center of PR3, and came back from the tunnel before snowing would not become heavy.

Details

Basically most of the works today was to confirm what we had done in the last year (19322) roughly. Firstly, we adjusted IMMT1 and 2 in believing the previous oplev centering would be also effective today. Then, without laser levels, we checked the IR beam positions on IMMT1 and  IMMT2, while the IMMT1T QPD was illumiated by the IR beam; we did not care so much about the precise "centering" on the IMMT1T QPD today, as IMC seemed not so nice aligned; maybe before closing these chambers we need to revisit this point. Anyway, the IR beam spots on IMMT1 and 2 seemed roughly centered.

Then we roughly checked the IR beam centering on PRM. This time we did not use the target, because the last year we adjusted the PRM traverser much in lateral and rotational, so the target plate must be re-adjusted according to the new line connecting the central points of IMMT2, PRM, and PR2. To put this more bruntly, we can say, if the IMMT2 and PR2 are now center-to-center, then PRM is the one that must be moved with the traverser, and the target plate must be re-adjusted according to this later. Today we did not do this, and just went to PR2 to see the situation.

We also confirmed that the IR beam centering on the PR2 with the target plate. Nice. Then we turned on some damping controls (maybe Ushiba-kun would report it later), and the damping seemed working well.

Then we went to PR3, and checked how much the IR beam spot diplaced from the center of the target. While I was looking at the beam spots with an IR viewer (sorry, I could not take a nice photo as attached... the upper shinig spot is of IR beam, the lower one is GreenX on the PR3 target through the IR viewer), Ushiba-kun adjusted the PR2 pitch and yaw to bring the IR beam spot to the center of the target.

We will do the next steps tomorrow.