Betsy, Travis, Jason, Rick First Contact was peeled from the ETM surface this morning. No First Contact remnants were observed on the surface. Particulate counts, using the "Green Lantern," were in the 2-5 particles per square inch range, down from the 5-10 particles per square inch seen before applying the first contact. The composite image attached below contains six images. The upper row of three were taken before applying the First Contact and the lower row of three were taken after the First Contact was removed. For all images, the surface of the ETM was illuminated with a green LED flashlight. For the four images on the left the flashlight was held by hand. For the two in the right, the flashlight was set in the Arm Cavity Baffle in an effort to make the illumination the same for both images.
Adding to Rick's alog above, we are not sure we see much change in the particulate as observed via the pcal camera with flashlight illumination. We did see some improvement of the particle counts when we counted using the green lantern (lights up across the surface). We blew the optic HR surface for ~10 minutes and did not see much particulate move off.
Particle counts:
We appeared to see more particulate in this chamber than in BSC10 - we noted about 2 times the amount of particles floating through the flashlight beam than in with the ETMy. However, the particle counter counted 0 counts in all sizes when I sampled before we entered the chamber, so it must all be from moving around. We counted the following just after applying FC to the ETMx and while wiping our way out of the chamber
1090 0.3um
560 0.5um
400 0.7um
260 1.0um
Chamber closeout order:
Pulled FC
Blew optic with dei N2 Top Gun for 10 mins
Restored ACB to normal position*
Unclamped optic
Unlocked ISI
Laid witness plates and 1" witness optic (2 on floor, 2 on QUAD sus)
Removed all tools/guns/lights, etc.
Took TFs of ISI and QUAD for health checks
* When we looked at the ACB earthquake stops after replacing it and noticed that one was very high in the hole. After bantering and worrying about it for an hour, we discovered this alog which says that this is actually how it was tuned to begin with. Jim checked and doesn't see unhealthy vertical TFs, so we're leaving it again.