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Reports until 19:25, Thursday 16 January 2025
Vacuum Systems General (GQuEST)
Daniel Grass - posted 19:25, Thursday 16 January 2025 - last comment - 18:05, Friday 17 January 2025(12079)
Flanges moved around and installed on Laser Filter Cavity and Demonstrator Interferometer Vacuum Cubes

[Jeff, Daniel]

We placed a 10" blank flange on the Input Laser Filter Cavity (LFC) Vacuum Cube North End and tightened the screws to 34 Nm. We moved 10" flange with electronics D-Subs to the Demonstrator Interferometer Vacuum Cube (transmitted arm) so that we can lock the interferometer with a piezo. I tightened the screws to 13.6 Nm with one pass but decided to go home and not work alone. These flanges and faces on the cubes were a bit dirty, so we did some cleaning with the wipes meant to clean inside vacuum chambers. We moved the 10" to 4.5" zero length reducer flange to the top of the Input LFC Vacuum Cube, but the screws did not want to go in more than ~0.35" before almost all of them had a lot of resistance. The holes seem tapped and deep enough; I measured 1.8" from the top of the flange to the bottom of the hole. I think we need to re-tap or clean up these threads. Ian recommended getting a thread chaser kit. I think this one would be a good option. We placed foil on the newly exposed face on the Input LFC Vacuum Cube. I want to seal up the flanges before potentially making chips on top of the vacuum chamber.

Comments related to this report
Daniel Grass - 18:05, Friday 17 January 2025 (12082)

I tightened the screws on the 10" electronics flange to 34 Nm on the IFO.

GQuEST SHG
Jeffrey Wack - posted 14:59, Wednesday 15 January 2025 (12078)
AOM troubleshooting

[Torrey, Jeff]

The second AOM was not working, and this was resolved by unplugging the BNC on the AOM and replugging it.

There was no 775 light reaching the second filter cavity, so we investigated the second AOM on the SHG sled. After confirming that it was receiving RF power correctly by swapping cables with the first AOM, we removed the cover and visually inspected the crystal to ensure it looks good. We added a pickoff mirror and a camera after the AOM and could see two spots and fiddling with alignment for a while we could still not get the power of the frequency shifted beam to an acceptable amount (we want to see roughly 50/50). Finally after unplugging and replugging the BNC the two spots were about equal.

We then had to realign the fiber coupler. We left it at

76 uW in, 40uW out -> 52% efficiency

Vacuum Systems General (GQuEST)
Daniel Grass - posted 16:37, Tuesday 14 January 2025 (12076)
2.75 in 1550 nm AR Coated Viewport installed on Laser Filter Cavity Output Vacuum Cube; Vacuum Cubes moved around

[Jeff, Daniel]

The clean room smelled less of smoke, so I took some more particle counts at 2:50 PM, after ~150 minutes of the air purifier being on in B111A, to ensure we can do vacuum work in B111B and to see how well the air purifier is working. Other areas are also getting a lot better, so all of this improvement is very unlikely to be from the air purifier.

  B111A North small table B111A Outside clean rooms west of north small table B111B Control area B111B Outside clean room by northeast shelves B111B Inside clean room B111 Antechamber
0.3 um 0 46 88 59 0 1182
0.5 um 0 9 42 28 0 283
1.0 um 0 4 23 20

0

165

The particle counter in the B111B clean room read 14/0/0 on a first reading, so I more carefully turned it on by staying under the particle counter and it then read 0/0/0.

 

We installed the 2.75" 1550 nm AR Coated Viewport onto the Laser Filter Cavity (LFC) Output Vacuum Cube with an annealed copper gasket. The gasket had some discoloration/very light scratches on one face, but I think this is ok. We tightened the screws loosely, then tightly by hand, then by hand using the socket on the screws, then using the wrench with my hand near the bolt, then using the full length of the wrench, then using the torque wrench at 6 Nm, 7 Nm, 8 Nm, and finally at 9.6 Nm. 9.6 Nm was enough so that the flange appeared to be fully tightened. Special care was used to ensure we didn't touch the glass of the viewport flange. 14 Nm was used for the 2.75" blank flange and regular copper gasket.

We then pushed the LFC Output Vacuum Cube into place, secured it to the optics tables, and brought the LFC Input Vacuum Cube closer to the edge of the table so that we can more easily work on it. We tightened that cube to the table as well. 

GQuEST Output Filter Cavities
Torrey Cullen - posted 15:16, Tuesday 14 January 2025 (12075)
First Cavity Lock post 2025 Eaton Canyon Fire

We had been discussing if the extremely poor air quality due to the fire had effected our superoptics in the OFCs. To check this I performed a couple quick ringdown measurements on OFC1. For both wavelengths, the finesse of the cavity is close to measurements before the fires. It seems uneffected. For reference F = pi * c / L * (measured tau in screenshot).

Images attached to this report
Environmental Dust/Particulates
Daniel Grass - posted 14:00, Tuesday 14 January 2025 (12074)
Particle Count Measurements on January 14, 2025 in B111, B111A, B111B

I took some particle counts today with the full 1 minute capture time. They are much better than yesterday.

B111A North large table North small table South large table South small table Outside clean rooms in middle of room south of curtain Outside clean rooms west of north small table before air purifier was turned on  Outside clean rooms west of north small table after air purifier was turned on for ~7 minutes
0.3 um 9 1 411 1 56 145 81
0.5 um 2 0 50 0 19 52 26
1.0 um 0 0 13 0 12

34

17

See attached photo for the location of the air purifier (with a newly installed filter and run at fan setting 3 with UV on) and the particle counter for the last two measurements.

 

B111B Control area Outside clean room by northeast shelves Inside clean room
0.3 um 3526 77 1
0.5 um 1598 48 0
1.0 um 579 26 0

The 0.3 um particle happened within the first second of the minute capture time, so might be been caused by me setting it up (I didn't have a beard net or gloves on).

 

Other B111 antechamber
0.3 um 1516
0.5 um 489
1.0 um 235

 

For each respective location outside the clean rooms, these are some of the lowest particle counts we have taken. Particle counts are a bit elevated inside the clean rooms.

Images attached to this report
Lasers Amplifiers
Torrey Cullen - posted 11:33, Tuesday 14 January 2025 (12073)
Lasers on in B111B

Laser and amplifier are being turned on following 12065. After the work done on the interlock system it does not seem like the signs are functional yet. 

Environmental Dust/Particulates
Daniel Grass - posted 14:43, Monday 13 January 2025 (12071)
Particle Count Measurements on January 13, 2025 in B110, B111, B111A, B111B, and B111D

I took some particle counts today with the full 1 minute capture time 

B111A North large table North small table South large table South small table Outside clean rooms in middle of room Outside clean rooms west of north small table
0.3 um 6893 9768 5309 3362 15614 15383
0.5 um 873 1098 595 436 2075 2088
1.0 um 339 395 214 156 877 854

Something is clearly wrong inside the clean rooms. Also quite elevated (~20x) from September outside clean room. Please note the exposure time was 1/6th as long in the September measurments.

 

B111B Control area Outside clean room by northeast shelves Inside clean room
0.3 um 18352 4460 0
0.5 um 2433 655 0
1.0 um 971 305 0

~2x elevated from September outside the clean room by the northeast shelves.

 

Other B111 antechamber B111D
0.3 um 17033 13006
0.5 um 3581 2214
1.0 um 1965 1104

~10x elevated from September in B111 antechamber. First measurements in B111D to my knowledge.

 

B110 Outside next to fume hood Inside fume hood
0.3 um 14887 244330
0.5 um 2555 2441
1.0 um 1251 1169

Yes, the 0.3 um particle count was that high. First measurements in B110 to my knowledge. 

Environmental Dust/Particulates
Torrey Cullen - posted 18:12, Sunday 12 January 2025 - last comment - 19:57, Sunday 12 January 2025(12067)
Particle Readings after January 2025 Eaton Canyon Fire

[Torrey,Jeff,Ian]

We decided to check on air quality in bridge/lab. The hallways and offices are suprisingly decent. As you enter the lab it is more and more smokey. Inside the cleanroom in B111B is by far the worst smelling. May need to replace the filters in the cleanroom fans. For now though, cleanroom1.jpg and cleanroom2.jpg show no particles above .3 um in the cleanroom.  Outside the cleanroom the particle counts seem higher than normal, would have to find old log posts with these numbers though.

Additionally we did a quick sweep in B111A. It smells like an animal has died in the vents somewhere. I will look into putting in a maintenence request tomorrow morning. Particle count where the smell is the strongest: deadanimal.jpg. Additionally the B111A cleanroom fans do not seem to be on. insideB111Acleanroom.jpg (this is on the table with the RQB stuff).

Images attached to this report
Comments related to this report
Daniel Grass - 19:43, Sunday 12 January 2025 (12068)

From September when we were moving in: https://mccullerlab.com/logs/lab/index.php?callRep=11873

Daniel Grass - 19:57, Sunday 12 January 2025 (12069)

These results are ~5x worse in B111B outside the clean room and ~30x worse in B111A outside the clean room. There could be some variance in room location, but surely not 30x unless the particle counter was in a really weird location or there was a lot of actively right before and during the count.

Non-image files attached to this comment
Environmental Dust/Particulates
Daniel Grass - posted 19:28, Tuesday 07 January 2025 (12066)
Smoke smell in B111

It smells like smoke in B111, probably from the Eaton Fire. I couldn't take a particle count since the particle counter was dead and I couldn't find the cord to charge it.

Lasers Amplifiers
Daniel Grass - posted 19:27, Tuesday 07 January 2025 (12065)
Laser in B111B shut off due to risk of power outage from high wind or associated fires

I turned off the amplifier and seeder in B111B following our SOP.

 

Vacuum Systems General (GQuEST)
Daniel Grass - posted 17:13, Tuesday 07 January 2025 (12064)
Stuck Gasket removed with Locking Pliers and 4.5 in Blank Flange installed onto LFC Vacuum Cube reducing flange

I removed the stuck gasket (likely made of annealed copper) from a 10" to 4.5" reducing flange on the side of an LFC Vacuum Cube with the smallest of the 4 locking pliers I cleaned. I didn't try the other 3 locking pliers. I think I very lightly scuffed the inside of the vacuum area, but the knife edge looked good. I added a new 4.5" copper gasket and 4.5" blank flange and tightened the screws.

Vacuum Systems General
Daniel Grass - posted 15:49, Tuesday 07 January 2025 (12063)
Locking Pliers for UHV Class B Use Cleaned

I cleaned 4 locking pliers made of chrome vanadium steel for UHV Class B use (use around parts that will go inside vacuum). Per Maty Lesovsky's recommendation for greasy parts made of chrome vanadium steel, I cleaned the parts in acetone and then isopropanol. Water would rust the pliers, so I did not use it.

These pliers are specifically meant to remove suck gaskets, but these can be multi-purpose if kept clean.

Lab Infrastructure General
Daniel Grass - posted 15:28, Tuesday 07 January 2025 (12062)
Stainless Steel Container for Acetone Cleaned

I cleaned a stainless steel container and lid to clean parts with acetone. I rinsed and brushed the inside and outside with 1:30 Simple Green:DI Water, washed the outside with DI water, sonicated for 10 minutes with this solution inside the container, washed the inside with water, sonicated for 10 minutes with DI water, washed out the inside with acetone, and sonicated with acetone for 10 minutes. I then labeled the container and lid.

GQuEST Output Filter Cavities
Torrey Cullen - posted 13:35, Thursday 19 December 2024 (12061)
Chaining OFCs

[Jeff,Torrey]

Yesterday I attenuated the input to OFC1 1550 path so TRANS PD wasn't saturated and didn't mention it so I am doing so here. This gives an input to the cavity at 4.6 mW. The output while locked is 1.22 mW. It seems as though the cavity is not particularly closed to critically coupled, although this is not suprising based on the depth of the REFL dips. We chose a lens to put the output beam of OFC1 into a fiber that will connect to OFC2 input. The measured output of this fiber was 1.06 mW, which is an efficiency just over 86%. This could be improved but for now we will keep it here. I think for this measurement as long as we know of all the optical losses along the path, we don't care if there are any. This obviously changes when we are trying to get signal photons to an SNSPD. Additional sources of losses leading into OFC2:

-FC/APC connection between two fibers ( like this ). Quoted at .5 db insertion loss.

-A 50:50 fiber beamsplitter is plugged into the other side of the mating sleeve. This was to be able to do OFC2 and OFC3 things at the same time. This will be changed eventually but keeping it for now as I think its still useful. Quoted at 3.4 dB insertion loss and then obviously a 50:50 split. In a loss calculation refer to this for more details.

-Any optical losses between fiber output and input to cavity. Should be <1%.

After lunch we plan on swapping the fibers out so that the OFC1 output is seeding OFC2. Before doing this we took a mode scan of OFC2 with its original seed light. This is to compare mode scans directly between swapping the fibers. More to come after lunch.

Images attached to this report
Vacuum Systems General (GQuEST)
Daniel Grass - posted 17:03, Wednesday 18 December 2024 (12060)
10 in CF Flange to Rotatable 8 in CF Flange 12 in long Custom Nipple Installed on Laser Filter Cavity Output Vacuum Cube

[Jeff, Daniel]

We attached the 10 in CF Flange to Rotatable 8 in CF Flange 12 in long Custom Nipple onto the Laser Filter Cavity (LFC) Output Vacuum Cube. When dropping in the copper gasket, we used 12-14 bottom bolts instead of the usual 4 because the nipple applied a large torque pulling the top away from the cube. Otherwise, we installed it as usual and I tightened the bolts to 34 Nm.

Vacuum Systems General (GQuEST)
Daniel Grass - posted 17:49, Monday 16 December 2024 - last comment - 16:41, Tuesday 14 January 2025(12054)
CF0600S2, 4.5 in blank flange, and 2.75 in blank flange added to LFC Vacuum Cube

[Jeff, Daniel]

I tightened the 10" to 4.5" zero length reducer flange on top of the vacuum cube.

We added the CF0600S2 6" to two 2.75" CF Multiport Reducer to the 10" to 6" CF Zero Length Reducer. We did the usual method of placing the flange using some top screws to hold it, adding 2 bottom screws, remove the top screws, tilting the flange up, dropping in the gasket, and then adding the remaining screws. Only a few screws were accessible with our torque wrenches, so I tightened the screws by hand in a star pattern (going every 5 screws with 16 total). We bought this part (as part of a set) so that the torque wrenches can reach all the screws.

We took off a plastic cover and cleaned the 10" to 4.5" reducer flange, which was covered with duct tape (and duct tape residue) outside where the 4.5" flange goes (and outside the vacuum). 

We added a 4.5" CF blank flange to this 10" to 4.5" reducer flange on top of the vacuum cube. Because there were only 8 screws, I started at a lower torque, 6 N m, did a star pattern every 3 screws so that every screw was tightened twice, and incremented the torque by 1 N m until the torque was 12 N m, then I incremented the torque by 3 N m until 34 N m when the flange seemed tight enough (stainless steel contact around ~70% of the surface).

We added a 2.75" CF blank flange to the CF0600S2 (where the laser view port will not go) and attached it with the plate nuts. I lightly torqued by hand and used the torque wrench starting at its minimum value of 6 N m. I tightened every 2-3 bolts until the torque wrench did not tighten the bolts further, then incremented the torque by 1 N m until 14 N m. For the laser viewport, we will use the annealed copper gasket, which will require less torque to tighten.

Next, we will swap out the 10" to 2.75" reducer flange for a 10" to 4.5" reducer flange because the 10" to 2.75" flange is needed for the demonstrator IFO.

Comments related to this report
Daniel Grass - 16:41, Tuesday 14 January 2025 (12077)

I forgot to note at the time that the gasket for the 6" flange had some discoloration/very light scratches on one face, but I think this is fine.

Environmental Dust/Particulates
Daniel Grass - posted 18:15, Thursday 19 September 2024 - last comment - 14:48, Monday 13 January 2025(11873)
Particle Count Measurements in B102, B111, B111A, and B111B

I took some particle counter measurments in B102, B111, B111A, and B111B. In all the clean rooms, the particle count was 0. These clean rooms were the B102 cleanroom with the optical cavities, the B111B mobile cleanrooms, the Southern most B111A long table, and the Northern most B111B short table.

I also took some 10 second particle counts outside the clean rooms. Data is 0.3 um count/0.5 um count/1.0 um count)

B102: 1268/72/28 (there were lots of people and activity during this measurment)

B111 (entryway): 495/46/28

B111B: 177/51/39

B111A: 95/17/13

These seem like very good measurments.

The particle counter is on the optics tables in B111B.

Comments related to this report
Daniel Grass - 19:58, Sunday 12 January 2025 (12070)

It should probably read "Northern most B111A short table" considering there is no short table in B111B.

Daniel Grass - 14:48, Monday 13 January 2025 (12072)

Data extrapolated to a full minute for easy comparisons:

B102: 7608/432/168 (there were lots of people and activity during this measurment)

B111 (entryway): 2970/276/168

B111B: 1062/306/234

B111A: 564/102/78

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