J. Oberling, N. Kijbunchoo, B. Weaver

This morning we installed the PBS in the HWSx path.  The 2 attched .png files show the desired before and after configuration of the HWSx beam path.  Unfortunately we did not have enough room to install the transmitted path as shown in the picture, so we moved HWSX_ALIGN_M1 and installed the lens and detector parallel to the reflected path (see before and after photos).  As it stands right now, HWSX_POSN_SENS2 is measuring the beam reflected from the PBS (s-pol (perpindicular)) and HWSX_POSN_SENS1 is measuring the beam transmitted by the PBS (p-pol (parallel)).  All optics are turned slightly to prevent back reflections from getting back into the IFO.  A short summary of our procedure:

• Install PBS and align, ensuring back reflections are not getting back to the IFO.
• Move and align, in this order, ensureing back reflections are properly handled:
  • HWSX_ALIGN_LENS2
  • HWSX_POSN_SENS2
  • HWSX_ALIGN_M1
  • HWSX_ALIGN_LENS1
  • HWSX_POSN_SENS1
• Double check to make sure all back reflections are either missing the top periscope mirror or blocked in some way.
• Block each detector in turn for 5-6 seconds, noting the time of each.

Nutsinee noted the times we blocked each detector and will post that in a follow up comment to this alog.  This completes WP 5627.