Dew point measurement taken this morning read at -43.7 oC. Measurement taken before any activity inside chambers. Soft covers were on HAM5 and HAM6, HAM7 remains isolated and a bit pressurized.
FAMIS 26468 -Capture Monthly--Trend HEPI Pump Pressures and Drives
There was a number of spikes over a few days, that I expect to be associated with the venting and jumping on the HEPI platforms.
Mon Jul 29 08:11:00 2024 INFO: Fill completed in 10min 56secs
Gerardo confirmed a good fill curbside.
TITLE: 07/29 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: MAINTENANCE
Wind: 9mph Gusts, 4mph 5min avg
Primary useism: 0.44 μm/s
Secondary useism: 0.10 μm/s
QUICK SUMMARY:
Sun Jul 28 08:10:21 2024 INFO: Fill completed in 10min 17secs
Sat Jul 27 08:09:47 2024 INFO: Fill completed in 9min 43secs
At the EX station, the purge air supply was switched on from 09:46 until 18:16 with the highest load possible, according to WP #12001. The temperature of the mechanical room and the environment was monitored periodically. It can be concluded, that the HVAC system was able to hold a ~5 deg F temperature difference with the outside temperature. For more details, see graph. The temperature was rising rapidly after switching on the purge air supply. Then, a big decrease can be seen - this could have 2 reasons: (i) the sunlight just went away from the front of the building, and/or (ii) the HVAC system reacted like this. In the end, the HVAC system consolidated the temperature at 91.4 deg F. This whole measurement was carried out as additional information for the installation of the new purge air supplies.
TITLE: 07/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: Tony
SHIFT SUMMARY: More KTP work in the optics lab, the wedge broke during work today but we have a spare. The LVEA remains in SAFE.
LOG:
Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
---|---|---|---|---|---|---|
15:08 | SQZ | Sheila | Optics lab | LOCAL | KTP work | 16:55 |
15:39 | PEM | Robert, Carlos, Milly | Yarm | N | PEM investigations | 19:09 |
15:50 | SQZ | Keita | Optics lab | LOCAL | Join Sheila, KTP work | 17:53 |
16:06 | CAL | Fransisco, Cervane | PCAL lab | LOCAL | PCAL work | 16:24 |
16:35 | VAC | Janos | EndX | N | Turn on air supply for the day | 17:35 |
16:39 | VAC | Jordan | LVEA | N | Purge air / Dew point checks | 16:59 |
17:07 | SQZ | Sheila | Optics lab | LOCAL | KTP | 17:53 |
18:18 | VAC | Jordan | Ham6 | N | RGA | 18:51 |
19:47 | SQZ | Sheila, Keita | Optics lab | LOCAL | KTP work | 22:52 |
21:01 | VAC | Jordan | Ham6 | N | More RGA | 21:57 |
21:12 | PEM | Robert, Milly, Carlos, Neil | Yarm, Site | N | PEM investigation | 23:23 |
23:22 | CAL | Francisco | PCAL lab | LOCAL | PCAL work | Ongoing |
Keita, Sheila
Summary: We chipped the spare KTP crystal this morning, and this afternoon installed the back up spare that Rodica had shipped. We've adjusted the roll, and the pitch angle seems better than the crystal that we removed. So this should be ready to go into the chamber first thing Monday morning. We have many photos from today, which will be attached and annotated to this alog later.
Following on From Jason's alog 79319
With this placement of the damaged KTP in it's assembly, where the assembly is bolted perpendictular to the beam path, and a wave plate to mix the polarizatoins upstream of the KTP, we have 13.5mW in the p polarized beam (see first attachment which is a diagram Paul sent us this morning), 16.3mW in the s polarized beam, and 2.3 mW in the AR surface. This is not set up with the AOI that the AR coating is designed for, which is why the AR beam is large, we can take advantage of this to set the pitch by setting the AR reflection parallel to the table..
With the original KTP in place, the AR reflection isn't parallel to the table it is pitched up by 10/(530 +405 mm) about 11 mrad. The optic lab beam is hitting the KTP a little below the burned spot, which would have been on the +X side in chamber. The burned spots are on the side closer to our alignment laser.
Before taking it out of the mount we took a variety of photos showing the damage spots position. We did not find any indium foil in the mount, Paul had warned us that there might be indium between part 5 and part 9 of D2000038.
As we were placing the new crystal in the mount, we left the set screws (11) that hold the peek loose, and held the piece upsidedown while we screwed in the bolts labeled #10 to hold on the aliuminum plate. It chipped as we were tightening the bolts labeled 10 in D2000038. After some discussion with Rodica, Paul, Gabriele, we went back to the lab to take photos of the chip and try to understand how the chip happened. We have photos showing that the crystal was proud of the top of part 5, the orientation of the black metal piece. After we removed the black front plate, we could see that the KTP was firmly stuck in part #5, with the wedge stuck. Keita had to push on the back of the crystal to get it loose.
Keita made a series of measurements using calibers:
Chipped KTP: (agrees well with the drawing: E1900284)
part 5: https://dcc.ligo.org/DocDB/0171/D2000567/001/D2000567_A%2B_OFI_KTP_Wedge_Holder.pdf
peek:
total height (max): crystal + peek = 0.885+0.1105 = 0.9955 inches, smaller than 0.2mm than the height of the slot.
cratered KTP:
We then did a trial run (using the chipped KTP) of an approach that we think avoids the problem of letting the KTP get wedged in the holder. We set the KTP on several wipes on the bench, and set the peek underneath it. We then slid the holder (part #5) over this whole thing, which went smoothly, and tightened the set screws. After flipping it over, we can see that the KTP is not proud of part #5, and it sits nearly flush to the front of the holder. We could then easily attach the black front plate. We decided to do this with the final spare, which had 2 small chips on the edge.
With that spare installed in the assembly, we adjusted roll using the alignment laser that Camilla and Jason set up. We wanted to adjust roll so that the transmitted beams were level to the table, since we know that the laser bea we started with were parallel to the table. The roll adjustment was sticky, and tightneing the set screw tended to lower the transmitted beams. The beams transmitted are off in yaw compared to the ones from the cratered KTP, by about 7mm/870mm + about 8 mrad. We had difficulty seeing the AR reflected beam, but we can see a tiny beam with all the lights off (this suggest that the reason the beam was so bright before was the coating damage, not the AOI of the crystal in our set up.). At 820 mm from the KTP, the AR beam was about 1 mm too low, so it's pitched down by 1mrad.
We think this is about as good as we can do by adjusting with this mount, so we are satisfied and will leave the KTP assembly under wipes and foil to be reinstalled on Monday.
Photos showing the location of the crater damage spots, and how the crystal was mounted in the holder as found.
Photos showing the chipped crystal. The second photo shows some small chips on the back edge, we noticed these just before the crystal chipped. Rodica says those look similar to things she has seen in these crystals, so this might be something that was present before today. The front of the crystal has a large chip and damage along the bottom, those both happened while tightening the bolt on the front plate.
Photos of how the damage probably happened. The crystal was proud of the aluminum holder, visible between the aluminum and the black piece in the first photo. The next two photos show that there was space between the back of the holder and the thick part of the wedge on both the top and the bottom.
The last 4 photos are side on views from 4 sides showing how crystal was sticking out in front of aluminum holder.
The MTP was lodged tightly in the aluminum holder and wasn't easily dislodged, the last photo shows how Keita slid the peek out from under it and the crystal was still stuck tight.
When we took the cratered KTP out to measure it, a speck of black seems to have fallen out of one of the craters.
final photos for today show how the beam out of the new crystal was off in yaw compared the the crater damaged crystal. The irises were placed on the transmitted beams through the crater damaged crystal by Jason before we swapped.
Video of the installation of new KTP in the KTP holder (without breaking it) was uploaded to https://dcc.ligo.org/G2401494 as it is too big to attach to alog.
Note that the table surface (and therefore the face of the holder facing the table in the video) is NOT perpendicular to the cylindrical surface of the holder. Attached is a cartoon of the side view of the installation shown in the video. (86 deg in the cartoon is just an eyeballing, but it should be larger than 80 deg, smaller than 90).
The problem seems to be that the height (which you cannot see in the cartoon) of the KTP as well as PEEK cushon (which you cannot see in the cartoon either) combined is so close to the height of the slot in the holder that a slight rotation of KTP relative to the holder around x axis will easily wedge the KTP in place.
For posterity, below is a table of KTP wedge serial number.
S/N | Description | ICS |
3005 | The original wedge with laser damages (aka cratored one). | TBD |
3004 | The first replacement that we chipped. | https://ics.ligo-la.caltech.edu/JIRA/browse/E1900284-2-Aplus-3004 |
3001 | Pristine one that we installed in HAM6. | TBD |
S/N 3004 and 3005 will be sent to GariLynn.
Another great pic of the laser damaged KTP.
Table of KTP wedge serial number with newly made ISC links for SN3005 and 3001. Thanks Mitch for making these records!
S/N | Description | ICS |
3005 | The original wedge with laser damages (aka cratored one). | https://ics.ligo-la.caltech.edu/JIRA/browse/E1900284-2-Aplus-3005 |
3004 | The first replacement that we chipped. | https://ics.ligo-la.caltech.edu/JIRA/browse/E1900284-2-Aplus-3004 |
3001 | Pristine one that we installed in HAM6. | https://ics.ligo-la.caltech.edu/JIRA/browse/E1900284-2-Aplus-3001 |
Tagging for EPO.
Closes FAMIS26445 last checked in alog78733
BRS-X appears to be drifting towards the upper limit, the temperature seems stable.
Closes FAMIS26319 , last checked in alog79120.
For the out buildings there were some fans turned off and on, EX looks like a fan was repaired yesterday.
For the CS, MR_FAN3_170_1 looks like it has gotten a touch more unstable the past day, and MR_FAN5_170_1&2 is quite noisy.
Fri Jul 26 08:08:56 2024 INFO: Fill completed in 8min 52secs
TITLE: 07/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
SEI_ENV state: MAINTENANCE
Wind: 0mph Gusts, 0mph 5min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.07 μm/s
QUICK SUMMARY:
h1calinj model has a RED excitation state on the CDS Overview MEDM because the continuous hardware injection stopped running Thu 25jul2024 16:08:57 PDT.
I'm looking into why this excitation stopped at this time.
Dew point measurement taken this morning read at -43.4 oC. Measurement taken before removing HAM6 -X door. Some demand from HAM5, and HAM6 with soft covers on.
Today's activities: - The purge air dew point was measured at the purge port: (9:15 am) -43.9 deg C, so it is consistently dropping in time. Some more specifics here: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=79306 - HAM6 -X door has been removed. The O-rings seem to be intact - The opportunity was taken for replacing the HAM6 RGA. It will be also re-wrapped with heat tapes, and after the chamber work ends, will be baked out. - Pressures: the arms' pressures slowly dropping (probably because of the weather is getting colder). The Y-manifold pressure is stabilized around 2-3E-8 Torr.
HAM6 RGA was swapped with a brand new Pfieffer PrismaPro RGA. We had not been able to connect to the old RGA since ~March 24, through the network nor locally using a laptop. The new unit has been installed and is currently prepped for bakeout once chamber work has finished.