Yutaro, Eleonora, Satoru(哲), Kiwamu,

Today we did two major activities; one is the re-alignment of the REFL path in vacuum, the other is the PRM adjustment.

This entry reports on the former while Miyo-kun and company will report on the latter.

Here is a list of what we did.

• PRM was temporarily aligned in such a way that the reflection beam goes back through the Faraday.
• We then confirmed that the REFL beam was almost being clipped by the last steering mirror in the IFI chamber.
• We shifted the last steering mirror toward the positive y-direction by 5 mm or so.
  • Although, the size of the shift was limited by the available space given by the Faraday's base plate.
  • This put the steering mirror to a suboptimal position where the beam was not quite centered on the mirror.
• We then moved the steering mirror (a.k.a. POM) in the IMC chamber by actuating on its picomotor.
  • By the way, we had to use the MCO picomotor deriver box for this job because POM didn't have a dedicated picomotor driver box.
  • After this work, we unplugged the phone jack cables for POM and plugged the ones for MCO back in.
• The beam dump, which is for capturing the reflection beams from the viewport, was repositioned.
  • Even though the reflection was not so bright, we were able to do this alignment simply using the laser card.
• The beam now hits the center of the last steering mirror in the IFI chamber. Also, the extracted beam hits the center of the first periscope mirror in air although the vertical position right now is too high and we will fix it later as it seems an issue with the in-air optics.
• We centered QPD for PRM oplev for reference of good PRM alignment, where we will come back tomorrow.