2021.03.30, StephenA

1. Viewport swap to nozzle that is not occluded by cryo shield = complete. All bolts on both Active Ion Gauge and Viewport have been torqued gradually (about a half turn at a time, around the clock dial) until the conflat seal was metal-to-metal. Periscope on damped optical rod was rotated to make room for replacement.

Before viewport swap - IMG_8487

After viewport swap - IMG_8502

2. Cryo RTD repair = complete. Two RTDs had been damaged during prior mounting efforts by me. I was able to repair the clamped RTD at the single damaged solder joint. I was able to repair the former Al-Block RTD by replacing the RTD element, and making a new direct attachment (not preloaded, not varnished to the aluminum block anymore)

Materials and set-up for solder repair - IMG_8491

Repaired Clamp-2 RTD - IMG_8494

Damaged Al-Block RTD - IMG_8492 (note short length between kapton strain relief and aluminum block was not ideal, one lead had already fractured and the second soon followed at the slightest touch)

Repaired, remounted Al-Block RTD - IMG_8495 (heater sandwiched underneath threaded adapter, clamp threaded into adapter, sandwiching RTD at top plane)

Remounted Clamp-2 RTD - IMG_8496 (RTD clamped at cold flange, strap is mounted)

Remaining Clamp-1 and Varnish RTDs are free - IMG_8497

Current readouts of CTC-100 controller, with repaired RTDs now behaving (note need to rename the Al-Block RTD) - IMG_8501

3. Next steps:

 - Karthik to install clamps, align in-air relay, and confirm positition of radiation shield aperture.

 - Remaining free RTDs to be mounted; current RTDs are mounted at Heater and Cold Flange, would be good to mount RTD at Work Piece/Clamp and at Outer Radiation Shield.

 - Radiation shield lids to be installed (might be easiest to install Outer Radiation Shield RTD after installing lid)

 - Mount lid, install bolts, pump down, turn on cryo cooler, the usual!