(Keita, Kiwamu, Corey)
After the Vacuum crew removed the door, and Jim Warner locked up the ISI (& removed the Contamination Control plates), we started TMS work. Summaries of the TMS activities are below:
1) Green Clipping
The ETMx Bias were:
In order to center the beam on the ISCT-EX REFL_PD, the ETMx was steered to the following biases:
After this Keita entered the chamber and looked for clipping. He started with the first steering mirror on the TMS, the one that showed very bright scattering back in Feb., and no clipping was observed this time though the beam was somewhat low, and there was some ghost beam hitting the top right edge.
Keita checked downstream optics and no clipping was observed either. No changes were made to the TMS optics alignment.
2) Strain Relief of QPDs
Ran into a problem with attaching the Strain Relief Parts (D1101911 & D1002110) to the QPDs. The problem was attaching the Strain Relief Clamp (D1101911) to the main QPD Housing. Unfortunately, the 1/4-20 hole in the housing had bad threads for two of the four QPDs. It's a thru-hole and screw could only go in a thread or two. My guess is the machinist tapped the holes from the backside with a tapered tap & didn't tap all the way through. So some of the threads at the entrance of the hole aren't cut completely.
Keita & Kiwamu went ahead and installed the Strain Relief Assy on the two QPDs which were fine.
As for the remaining two, we might use thinner 10-32 or 10-24 screws, long enough to go through the QPD base and the strain relief combined, and use a nut and two washers if such things are found. Otherwise we'll leave them without strain relief, as there's more than 1/4" of space between the cable collar and the metal part of the QPD support structure.
3) Krytox Beam Diverter
Corey went into the chamber, loosened the screw that attaches the shaft collar to the axle, slid the axle and the jewel bearing out on one side, applied Krytox, did the same to the other side, rebalanced the diverter by attaching 5 1/4" and one #8 vented washers as a counter mass, and assembled everything together.
This was done all in situ. Tested opening/closing via MEDM several times and it worked fine.
Jeff and Greg found the necessary screws, washers and nuts, so we'll do the rest of QPD strain reliefs the first thing in the morning, then rebalance TMS. We'll be done by noon-ish.
EX station is left in laser hazard.