IMC/IOT2L alignment - progress and an alignment issue to be resolved tomorrow

• the HWP was removed from the beam path into the IMC
• IMC power-in DCPD was centered
• this required moving a steering mirror and a lens in the DCPD path (bottom periscope mirror transmitted beam)
• recovery of the beam from the PSL into the IMC was not possible after those adjustments
• the rotation stage software was frozen, probably after the Beckoff reboot, and then restored
• with the beam from the PSL increased in power to ~46W, the MC2 Trans QPD was centered with the PZT (MC3 misaligned, no flashing)
• after centering MC2 Trans, there was a uniform disk of 1064nm light on the REFL path on IOT2L, but no centroid
• moving MC1 and flashing the IMC did not alter the beam on the REFL path in a significant way
• I believe the beam from MC1 is clipped in the second REFL periscope, and the uniform disk is scatter through the last baffle aperture
• a large shift in the beam from the PSL explains the alignment issues encountered today
• the plan for tomorrow:  
  • rest all optics and the PZT to known good values and align to the IMC/MC2 Trans from inside the PSL

- Jenne, Keita, Cheryl