As the weather changes I took this vent opportunity to reduce heat into the LVEA.These changes were made on Monday May 8.
HC5 - reduced to 8ma from 10ma (control value)
HC3A - reduced to 8 from 9
HC2A - reduced to 8 from 10
HC1A - reduced to 8 from 10
Installed the filter mounts under the PSL table. Given the tangle of cables and plumbing it will be necessary to rework this area to relieve the strain and entanglement of these cables and plumbing. A separate work permit will be filled for these activities. The photos below are of before and after mounting the filters.
Jason, Peter, Jeff B. Completed the mounting of the PSL chiller filters located under the PSL table. We also did some cable and plumbing cleanup.
I double checked the mechanical pressure gauges downstream of the 1.5 psi pressure regulator this morning after we noticed a high purge pressure value for the Vertex. The flow demand was high at this time as BSC3's door was off (HAM4 door too?) and these gauges were showing about 1/2 psig which is as expected for this flow demand. We resolved to adjust the "ATM" trim pot on PT120 before pumping tomorrow. I now am wondering if the pointers of these low pressure mechanical gauges were rotated past 360 degrees - indicating 1/2 psig but actually being 1/2 psig past n(360)? We need to close off the purge air supply and allow the Vertex to "blow down" and equalize to room pressure tomorrow to see what PT120A reads in orderto see what is going on.
Damping completed and flanges back on. No hitches. Three viton corks are in, preliminary laser vibrometry looks good. More later.
Gerardo, Vinny, Robert
First picture: Robert looking through the viewport at 9 o'clock position while inserting his hand into lower viewport hole at 8:00 position.
Second picture: A view through the lower viewport hole at 8:00 position. Black viton cork is inserted between the rib of the baffle and the chamber wall.
Pointer to the follow-up log entry: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=36147
Just to avoid any future confusion, the pictured location of the cork just above was not the final position. Based on feedback from the laser vibrometer, I moved it to 7:00, as pictured in the follow-up link given by Stephen.
Corey and crew finished work in HAM4 around ~1pm, while we continued to inspect and clean ITMx in a variety of ways. Around ~3:30 we (BSC3 crew of Travis, Calum, GariLynn, and I) determined that we should close up as cleaning wasn't removing all that we saw (see Calum's alog). Travis, Jim and I worked through the procedures to restore the ACB, ISI, and ITMX QUAD suspension, removing tools, wiping our way out. We then ran quick TFs on the sus and ISI which showed good and free results. Signatures were obtained of a few management staff still on site as a cross check that we are able to closeup. The door crew is finishing with the BSC3 door. Gerardo and Robert will next attempt the MCA1 baffle "grounding" through a port on the reduction flange near HAM2. Pumping down will commence tomorrow morning.
GariLynn Billingsley, Travis Sadecki, Betsy Weaver, Calum Torrie, Nicki Washington (and a BIG support crew)
ITMx inspection with green light and portable microscope revealed several scattering sites. The center most sites were located high and right of center. (Camera images will be attached soon.) One of these (the brightest / closest to center) is shown in the attached picture. It measure roughly 0.5 mm across the halo.
There were many scatter sites of the same character all the way out to the edge of the optic. At the edge we attempted to clean one of these sites using the following solvents (IPA, Acetone, red FC and clear FC) without success.
Following this local cleaning and the overall inspection we then cleaned the entire HR face as per normal procedures i.e. with red first contact (FC) spray along with the cone etc ....
Subsequent inspection showed no change to these scatterering sites.
For full chamber report see alog by Betsy.
GariLynn and team.
A few more pix of various "spots" we saw on the HR surface of ITMX today which did not come off with cleaning.
The first shows 2 very visible spots near the center of the optic which are the "halo" shaped nature that Calum/GariLynn show zoomed in above.
The second picture shows a small damage spot on the lower left of center on the HR surface that we believe has been on the optic since processing/coating/fabricating. This is a surface penetrating feature visible with back-illumination, and is the only one observed of it's kind.
The third picture shows a much different "feature" far right of center, that is not anywhere else on the optic, but interesting.
Here's one more picture of us illuminating the section of the ITMX-HR slightly below and right of center where we DIDN'T find much during inspection.
We did see similarly described "donuts" on the BS-HR - see Kates alog and Betsy's attempt at pictures in ~2014:
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=12876
Need to review to confirm related!
Calum
Now with the BS picture attempts during the time frame of Kate's alog:
https://ligoimages.mit.edu/?r=24661
https://ligoimages.mit.edu/?r=24659
Here are the articles I mentioned in the SYS call this morning. These are not the same, as they describe a short, intense burst of light on a clean surface, rather than the suspected culprit of a CW beam on a bit of dust. Never-the-less, perhaps they will useful or interesting.
Morphology of femtosecond-laser-ablated borosilicate glass surfaces
Adela Ben-Yakar, Robert L. Byer, Anthony Harkin, Jacqueline Ashmore, Howard A. Stone, Mengyan Shen, and Eric Mazur
Citation: Appl. Phys. Lett. 83, 3030 (2003);
doi: 10.1063/1.1619560
View online: http://dx.doi.org/10.1063/1.1619560
View Table of Contents: http://aip.scitation.org/toc/apl/83/15, Published by the American Institute of Physics
Femtosecond laser ablation properties of borosilicate glass
Adela Ben-Yakar, Robert L. Byer
Citation: Journal of Applied Physics 96, 5316 (2004);
doi: 10.1063/1.1787145
View online: http://dx.doi.org/10.1063/1.1787145
View Table of Contents: http://aip.scitation.org/toc/jap/96/9, Published by the American Institute of Physics
I've included a picture of some of the craters from the second paper (fair use)
Facts: Nothing was found where we were looking for the absorber, low and right from center on the HR surface. Aidan's plot showed ~25 mm down and ~25 mm Right. No particulate was seen standing proud of the HR surface. Nothing was found on the AR surface of the adjacent CP. The features found on the ITM HR surface were of uniform size ~0.5 mm, with no more than 50% variation in size. All of the characteristic spots were circular. There were various dark (uncontaminated?) shapes in the center of the circles - keyhole, linear, dot or uniform (filled) Features were found all over the optic including the very edge - Can’t say if there were any off the coating or not. No immediately apparent distribution. tried the following cleaning on a spot at the bottom edge of the optic to the left of the bevel damage. (in order) Acetone - scrub with cotton swab IPA - scrub with alpha swab DI water - scrub with alpha swab Windex - scrub with alpha swab clear first contact paint red first contact paint Within estimated beam waist we found 7 circular features counted 1 spot (very small) penetrating the coating (glowed when illuminated from behind) - believed to be present as polishing defect. Silica wafer, mounted parallel to ITM03, but low of the arm cavity baffle: no similar scatterers - only small particulate. 1” optic mounted perpendicular to ITM03 on the side of the compensation plate suspension structure: no similar scatterers - only small particulate. Speculation: Possible vaporization of particulate depositing on the surface. Possible contamination underneath the HR coating, present all along. Further investigation at: https://dcc.ligo.org/T1700193
Particle counts during the in-chamber work were taken a few times:
2:30pm PT during first contact work with 1 person in the chamber, 2 people just prio
| Count Size | 10am PT entrance to chamber - Jim was starting ISI locking, 1 person in chamber | 2:30pm PT during first contact work with 1 person in the chamber, 2 people just prior |
| 0.3um | 9 | 135 |
| 0.5um | 2 | 82 |
| 1.0um | 2 | 24 |
BSC3 DOOR WAS OFF FROM ~9am to 5pm PT.
TITLE: 05/09 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC STATE of H1: Planned Engineering INCOMING OPERATOR: None SHIFT SUMMARY: All employees not essential to the chamber work have been sent home due to an emergency event near the Hanford Purex plant. (http://www.hanford.gov/c.cfm/eoc/?page=290) - Door is back on HAM4. - Betsy is taking transfer functions for BSC3. - Work on baffle by HAM2 has not started. LOG: 14:43 UTC Jeff B. to cleaning area and LVEA to prep for plumbing work 14:53 UTC Ryan patching alog server 15:11 UTC Jeff B. back 15:18 UTC Student to see Mike L. through gate Notice for Hanford 200 E area to take cover Karen to end Y 15:29 UTC Jason starting PSL diode current adjustment 15:32 UTC Door coming off BSC3 15:40 UTC Cintas through gate 15:43 UTC Christine to end X. Jim took all ISIs to damped. 16:05 UTC Apollo and Coca Cola through gate 16:10 UTC Door is off BSC3 16:17 UTC Greg taking tour to bridge 16:21 UTC Corey to LVEA 16:22 UTC John to end X 16:31 UTC Filiberto to CER mezzanine to work on documentation 16:36 UTC Jeff and Jason to PSL to install bracket 17:20 UTC Aidan to LVEA 17:36 UTC Paradise water delivery 17:43 UTC Stay inside notice from Richard 18:44 UTC Filiberto out 20:29 UTC Vern and guest to LVEA 21:22 UTC Corey reports door is back on HAM4 22:28 UTC Restarted all nuc display computers per Carlos' request
16:51 UTC Jim and Betsy have asserted that the transfer function measurements have checked out for BSC3. Door going back on BSC3. Robert is working on baffle. 01:19 UTC Vern and Bubba report all chambers are closed.
Door is back on BSC3. Annulus is being pumped down. Door is back on HAM4. Annulus is being pumped down. Gerardo, Chandra, Kyle, Robert and Vinny in LVEA. Gerardo helping Robert put blanks back on viewports.
Kyle and Chandra are out. Chandra reports the blanks are back on the viewports.
Everyone is out of the LVEA. I'm heading home.
We were suspicious of a vacuum leak in X-beam manifold (see previous aLOG), but it may be a failing ion pump (half of the pump). Attached is a year scan of the two signal currents. We swapped out the old power supply with the new style. Pump current is relatively high ~700 uA vs. 90 uA on IP5.
We will continue to leak check this evening while we're set up for it. So far we've sprayed GV7, the Balzer RGA with long lever arm, and a couple ports and flanges. No leaks detected.
HAM4 chamber was open (door off) from roughly 10am - 2pm. The actual job of swapping out a TCS lens, taking photos, and adding a Contamination Control wafer went smoothly and fast. The only time-consuming issue was taking the transfer functions for SR2 & HAM4ISI (but Kiwamu, Betsy, & Jim eventually gave us a clean bill of health). I will make a more thorough entry later.
Full summary posted here: alog #36123.
Email from Richard: The Hanford EOC has issued a work release for non essential personnel. If you are NOT associated with the chamber work you should leave the site. Hanford has requested we take route 10 to the 240 route to exit the area. All of the site North of the Y-Barricade is being released so you may want to depart sooner than later. We have been given permission to restore the HVAC. Please drive safe as traffic will be getting heavy. Richard for Mike and John
I reset the PSL power watchdogs at ~15:45 UTC (~8:45 PDT). This completes FAMIS 3649.
