PeterK, JasonO, RickS

Yesterday afternoon and evening we realigned the beam path from the 70-W amplifier to the PMC, addressing the discrepancy in optical component mounting heights - 10 cm vs. 4".  All components for mounting lenses (lens mounts, rails, etc.) and the new Faraday Isolator located between the Front End and the 70-W amplifier were designed for a fixed optical height of 10 cm.  Almost all mirror mounting components, the 70-W amplifier, and the PMC were designed for a fixed optical height of 4".  The difference of ~1.6 mm is significant.

After the first turning mirror downstream of the 70-W amplifier and up to the last two turning mirrors (with PicoMotors) directing the beam into the PMC, we set the beam height at 10 cm.  Thus, the beams are obviously below center on all turning mirrors.

We removed the high-power AOM for the ISS and spent a few hours tweaking the modematching to the PMC.

Currently, the PMC visibility is about 75%.  We suspect that the alignment through the 70-W amplifier needs to be adjusted.

We left the system with the new PMC running at full power (about 70 W) and the PMC output power directed to the water-cooled beam dump directly downstream of the PMC.

We are modifying some of our alignment flags, designed for 4", to the 10 cm beam height.