PeterK, JasonO, EdM, RickS

Today, we swapped out the original PMC for one of the new "All-bolted" PMCs (see LIGO-T1700543-v2), S/N007 (photos attached)

We aligned the PMC, FSS and ISS paths, locked the servos and adjusted the light levels and gains.

When we increased the power into the PMC to ~ 20 W, we noticed that the modematching to the PMC was degrading.

We found that the first turning mirror downstream of the new 70-W amplifier is damaged (extremely bright glow where the beam is reflecting from the surface (if you zoom on the photo below you will see the bright spot on the surface - 9:00, slightly left of center).  This is likely the cause of the change in the beam characteristics with power.

We plan to swap this optic out first thing tomorrow.