cheryl.vorvick@LIGO.ORG - posted 18:16, Saturday 12 May 2012 - last comment - 09:37, Monday 14 May 2012(2836)
High Quality Viewports on BSC6 South Door are a Mess:
While working in BSC6, I looked at the two high quality viewports on the South door. I found that both have cleanliness issues, on the inside surface, that are consistent with failed cleaning practices. On the South door, the East viewport has a line that is about 4 inches long, and is in a shape that is consistent with a smear from a solvent being allowed to dry on the surface. The West viewport has approximately 10 droplets, with some up to 2 mm in diameter, that are consistent with water/soap droplets being allowed to dry on the surface. Next week, the history and inspection reports for these viewports need to be reviewed, and possibly a plan made, to try and clean them in-situ. Pictures are attached.
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Betsy and I have done a little investigating this morning. Nominally, the life cycle of a custom viewport looks something like this: Incoming inspection (Condition-dark background, bright light, looking for gouges/dings etc) Cleaning (We're on about the sixth version of the viewport cleaning procedure at this point so we'll check and try to determine just how these viewports were cleaned. Some possibilities: Liquinox with bake, methanol with bake, freon without a bake) Assembly (Very possible for stuff to be deposited during this phase.) Post-cleaning inspection/proofing (QA process-Worth a check to see how process takes place and whether/how the process may contribute to the particulate load and whether there is anything that may cause spotting. Nominally, the testing set up is Class B.) Installation (There is always the possibility that IPA was used during the install to aid bolt torquing.) There are a few things we can try for clean-up: First Contact, methanol drag wipe, freon drag wipe.