aLIGO LHO Logbook

H2 SUS

betsy.weaver@LIGO.ORG - posted 17:18, Thursday 08 December 2011 - last comment - 17:35, Tuesday 13 December 2011(1874)

BSC8 SUS Cartridge Install Prep

This afternoon, after the final B&K hammer measurements were complete, and SEI locked the ISI and began their preps, I began securing the FMy and ITMy for lift-off.  Because the First COntact that was on the ITMy HR was many months old, and had been peeled down for IAS purposes numerous times over the last 2 months, I removed it and put a fresh coat on, including a new tab at the top.  I observed a lot of particulate on the optic after the peel and attempted to remove them with alpha swabs and the N2 gun (gun also used intermittently during FC removal).  This was cumbersome and while doing it I (and Corey over my shoulder) noticed some streaking pattern not from the First Contact, as well as some First Contact PEEK mesh patterning on the optic.  More pictures to come.  So, I gave up on the dabbing and blowing and reapplied the new FC coating.

Then, I secured all of the EQ stops on both the FMy and ITMy, with the exceptions of:
- 2 nuts (missing) - one on each UIM side stops, and
- the ITMy Top Mass Blade Stops, which require removing the Top Mass BOSEMs.  The masses and blades above and below are rock solid however, so this is fine.

I then added the new "finger" assembly which acts as a 20mm gap stop between the ITMy AR and the CP HR.  This assembly, however hangs down below the QUAD structure and may be a problem for the cartridge, but is easy to remove tomorrow if needed.

I also added the transport pins to the vibration absorbers on both suspensions.

I covered the FMy.

Comments related to this report

corey.gray@LIGO.ORG - 12:48, Friday 09 December 2011 (1880)

Link

I took some over-the-shoulder photos of the H1ITMY as Betsy was working on it. The photos are in ResourceSpace, here.

It's hard to manually focus on the stuff we were looking at, but I think we have a few photos where we were able to capture some of the particles/marks on the surface of the optic. Saw a little bit of everything as far as contaminants on the mirror surface: dried liquid stains, dust particles, chunk of First Contact (due to a hole on the First Contact film), and some weird patterned ("pixel-ated" Matrix-esque) marks.

Gripes about ResourceSpace:

Why can't we have individual captions for every photo instead of the useless caption which just has a date & time. I named each of my photos, so you can sorta get some info about each photo under the "Original File Name" field.
Wish we could edit the order the photos are arranged in Collections.

corey.gray@LIGO.ORG - 13:00, Friday 09 December 2011 (1881)

Link

Grrrr.....yeah, it's not intuitive how to post Resource Space links (yet another gripe).

Anyways, the REAL link for the photos I took are here:

https://ligoimages.mit.edu/?c=877

betsy.weaver@LIGO.ORG - 13:40, Friday 09 December 2011 (1884)

Link

Further to Corey's elog regarding the contamination pictures of ITMy, following is my note to COC:
Yesterday, I removed the old FC from the ITMy HR and reapplied a new coating with a thin tab at the top which can be peeled in-chamber. Corey managed to take some great pictures of this and they are posted at the link on ResourceSpace below. (Note, the pictures are always uploaded in reverse order so the first picture is my new FC coating.) Long story short, there are 4 things to note regarding the surface of this optic:

1) Overall particulate - lots still on the surface - like 10-20 per square inch - Ugh. Performed the dabbing technique but gave up after a short stint because it seemed futile. (Used lots of N2 filtered DI gun flow throughout, which helped some but not enough.)

2) PEEK Mesh pattern seen down front of optic (recall, we applied a long tab back in Oct when we bantered about the idea to tear down a strip for IAS purposes. In the end we didn't do this and the full tab just pulled the whole top of the circle down for IAS). You can see the "matrix" like pattern in the center of the optic in some of the pictures.

3) When I pulled the FC circle, a little square tab stayed on the optic when I got down to just below center. Weird. It's like it had a cut and the FC peeled around it. I stopped pulling and pulled the circle in such a way to pull up the tab. A small horizontal line roughly 3mm in length remained on the optic almost on center line and a 1-2 inches to the right of center (when looking at the face).

4) A very strange "watermark" was apparent streaking across the top of the optic - very apparent in some pictures. It looked very reminiscent to me of the purple markings we observed on many iLIGO optics. Not sure what this is. Defect in the coating maybe - I have not looked up the CSIRO report.

As stated above, all of this was observed and then I reapplied a new FC coating as shown in picture 1 on the link.

betsy.weaver@LIGO.ORG - 16:30, Tuesday 13 December 2011 (1899)

Link

Today, Cheryl and I re-inspected the ITMy HR surface, which now has the ~week old First Contact sheet on it.  My subsequent email to GariLynn:

Hi GariLynn -
So, the good news is, the blue streaking that ran horizontal in a band across the ITMy HR peeled off with the new FC.  The bad news is, Cheryl has pictures of a newly observed band of contaminant running around the surface of the HR surface within 1" from the edge (so outside of the FC ring).  She'll post pictures soon of today's observations.

I will indeed need to do a fresh application/pull after all IAS needs are complete in order to pull any more streaking likely to be induced when we do the pull-and-close technique a few times over the next few weeks with this new FC sheet.  Not sure how we can get away from doing this in the future - maybe we just leave it exposed?  Then we risk particulate accumulation which seems worse (as FCing over particulate may scratch, and the amount of particulate is likely to be too much to remove via dabbing).

Not sure what the new stuff is - I'll make a larger diameter FC sheet next time.

-Betsy

betsy.weaver@LIGO.ORG - 17:35, Tuesday 13 December 2011 (1905)

Link

Cheryl's pictures from today:

https://ligoimages.mit.edu/?c=883