On the 5th I opened the soft covers on HAM6 to lock the ISI and noticed that one of the black glass pieces was broken. I'm posting a couple of pictures here. Betsy, JeffK and others have looked to see if we noticed this during the last HAM6 vent, but none of the pictures in the alog show this glass in any detail.
Do you think you should write an incident report on this?
No, I don't think this warrants an incident report, since I believe this is a laser burn which broke the glass, not some other "accident". It does warrant an FRS however, since we will likely need a better "fix" to this. Further details:
On Friday, Keita and I inspected this broken beam dump on the North side of the HAM6 table in chamber. I have more pictures attached below. When I carefully pushed the 2 pieces of broken glass back together (like a puzzle) on the mount, I could see a hole of missing glass (PIC 1 and 2 below). As well, there is a shard of black glass sitting on the table about 8 inches in front of the beam dump, maybe "launched" from the hole site of the glass piece (PIC 3, circled in BLUE). As well, there are 2 other burn marks on this same piece of black glass off to the left visible in the first pics.
Sheila is going to help me with another round of inspections here and help determine beam propogation. We will also look into timing with potential shutter/toaster fussiness, and HAM6 pressure changes to hone in on when this may have occured since April 2016 when it was deemed healthy.
While inspecting HAM6 last week, I also looked a bit at the "toaster" fast shutter. A quickish look it's wires did not reveal any burn spots. Pictures attached.
As well, there is another black glass beam dump in the NW side of the table, close to the viewport which shows what appears to be some burn markings (last Picture). Likely another FRS addition.
For further follow up on the broken beam dump -- identified as the OMC REFL Beam Diverter dump -- check out LHO aLOG 38998 and FRS Ticket 9196. Regarding the dump which has a "glancing blow" burn mark, that's the dump catching the OM3 TRANS beam. Indeed, the burn mark appears on the *outside* of the functional part of the dump. So, I don't think there's a need for action there (and hence no need for an FRS ticket).