Reports until 19:50, Monday 15 December 2014
H1 SUS
betsy.weaver@LIGO.ORG - posted 19:50, Monday 15 December 2014 - last comment - 20:31, Monday 15 December 2014(15634)
BSC10 ETMy-HR surface inspection

Betsy, Travis, Rick

After Jim finished locking the ISI this afternoon, Travis hopped in the chamber.  Using the Green LED flashlight (part of the "green lantern" kit) he immediately identified the 3 spots on the HR surface of the ETMy that last week's pcal images highlighted - 2 fairly large chunks of FirstContact (FC) remnants and one quite small one.  I also went into the chamber and with green and white flashlights we then identified the ring observed at 3" diameter around the center of the optic also due to previous FC sheets.  The 3 macroscopic remnants near the center of the optics look very similar to remnants we have observed on other failed FC sheet pulls, and were likely left on there from the March cleaning FC sheet, and not from the original sheet.  Why Margot and I missed them in March is beyond me.

We then:

Installed the ACB locking brackets and dropped the ACB down such that it was partially swung back.  (We did not use the wedge, but instead just let it hang in it's free and open state.  This allowed pcal to still see the optic but also gave enough clearance to attach the green lantern and also to paint FC.)

Installed the Green Lantern on the ETMy structure and reinspected the optic.  Again the large FC remnants lit up well.  However, the ring feature did not show up under this lighting condition.  (The flashlights were better for this.  The ring feature looked more like a staining or clouding that started at the 3" ring boundary and spread ~uniformly outward towards the edge of the optic.  There did not appear to be large macroscopic contaminants or FC remnants at this 3" ring boundary.

Rick took a few pcal photos (see attached) of the remnants and the ring using the green lantern and the green flashlight.

We secured the ETM TM with TFE rails on the EQ stops around the barrel of the optic.

We proceeded to paint FC onto the HR surface, making a nice thick coating after a few layers were applied - this took ~45 mins.  Note, we only observed "spider webs" on the FC sheet/brush toward the end of the 45 min and they were more noticeable around the TFE rail that was nearest the HR face which was likely charged and attracting or even causing(?) the webs.

Set the PETG cap on the face of the optic.

 

Tomorrow we plan to come in mid morning and then catch up with Richard/Fil to make the ESD connector swap midday.  After that, we can pull the FC and hopefully see that we have removed the remnants and improved the ring feature. 

Comments related to this report
richard.savage@LIGO.ORG - 20:21, Monday 15 December 2014 (15635)COC
Link 

The first image shows the ETM surface illuminated with the "Green Lantern."

In the second image it is illuminated with a green LED flashlight.

The third, zoomed image is illuminated with both the green lantern and the green flashlight and shows the large first contact remnants (the two bright vertical objects with ragged edges and the smaller object to the left), as well as the edge of the "ring feature" identified with the ~3" window in the first contact that was applied previously.  Although the two vertical objects are roughly aligned with the edge of the ETM telescope baffle in the background, this photo and in-chamber visual inspection clearly showed that they are debris on the front surface of the ETM.
Images attached to this comment
richard.savage@LIGO.ORG - 20:31, Monday 15 December 2014 (15636)COC
Link 

A few images of the process of painting the First Contact on the ETM HR surface attached below.

The last image shows the PETG cover in place to slow the drying of the First Contact.
Images attached to this comment