[Torrey, Jeff, Daniel]

We installed a second 6" CF Gate Valve onto the Laser Filter Cavity (LFC) facing the output cube. This is for the ion pump. Tightening the bolts was challenging with all of the other objects in the way. I don't think I maintained a consistent torque at the end of the tightening procedure as I couldn't fit the torque wrench in its torque limiting configuration. The bottom was showing more of the copper gasket than the top, so I started applying a bit more force. I believe I've tightened the bolts sufficiently and consistently enough to avoid leaks.

Since this is for the ion pump, I figured I should look more closely into what ion pumps, controllers, and cables we have from the Holometer. I found what I believe to be some controllers but I can't identify them. Based on a printed ion pump trouble shooting guide, the pumps appear to be from Duniway. The pumps we have appear to be the 30 L/s pumps (a bit tricky to identify from size but clearer from their weight and flange size), maybe the DSD-030-5125-M. I think the guide is from 2010. I also found a single cable that should go from the controller to the ion pump.

[Jeff, Torrey, Daniel]

We cleaned installed a 6" gate valve from the Holometer onto the top of the 6 way cross pointing towards the input. I placed the handle to be more accessible from the side of the table. I tightened the bolts by hand until there was steel to steel contact. I couldn't fit the torque wrench. 

I then added a 6" to 4.5" reducer flange on top of the gate valve and tightened the bolts to 34 Nm until there was steel to steel contact all around.

We then added the Agilent TwisTorr 74 Turbo Pump onto the reducer flange. We could not fit screws when they had washers attached, so we did not use any washers. There is *very* little tolerance for getting a wrench around the screw heads such that we had to center the pump more precisely than usual. Even with that, we could fit only the torque adapter wrench around the screw (and barely at that). I think we should buy another (not another set) that I'll grind/cut down to be open face/nearly open face for next time. I didn't find any 5/16" ID slotted washers on McMaster with small enough OD. I tightened the screws to 20 Nm as per the manual. The copper was still visible. It should be easy to determine if there is a leak here (although it would be indistinguishable from one within the pumping system) by shutting the gate valve.

I've started alignment of OFC3. I've decided to do 775 path first. It is aligned to the point where I see first pass light (i.e. passes through M1 and M2 and onto camera). As well as the second pass light interfering with the first pass to create fringes. In the past once I've been at this point, you scan around on the intercavity mirrors until you see the third pass beam, and then turn on some kind of cavity length/frequency scan to see flashes. I haven't found the third pass beam yet. Hopefully should have a third, functioning 775 cavity soon.

One note: In order for the reflected beam incident on the cavity to clear the input mirror I had to move the two input mirrors back about 1.5 inches each. I also rotated the mount for the second input mirror to give additional clearance. The REFL beam clears the input mirror but only by about an inch or less.

Logging an error message that popped up when using the LXM Control software. Unsure what it means. Mainly a reminder to myself to check the manual later.

I cleaned some 1/4-20 button head screws, 1/2" long with acetone and isopropanol since they were greasy. I used these and some spring tab t-nuts that don't slide down under gravity to reassemble the 80/20 structure to support the bottom and sides of the 8" CF to 6" CF reducing tee on the Laser Filter Cavity (LFC) Vacuum System. To be honest, I'm not sure how much it's actually helping support the weight. I'm also using a scissor stand platform to help with the weight. I did not assembled the 45° brackets since it will be easier to install them with more spring tab t-nuts. 

Note for others when assembling 80/20: a small hex key is great at positioning the t-nuts, especially the cheap ones that can slide around.

Note for me and others going forward: thicker viton (~1/4" thick) would make the contact between the 80/20 and the tee much better.

[Sander, Daniel]

I removed a 2.75" CF Flange Tee from a Holometer ion pump sub-system and cleaned tape residue from it. I then installed it on the North 6" to 2.75" zero length reducer flange (it is easily accessible from the side of the table). Sander and I cleaned and installed two 2.75" angle valves onto the tee, one on each side. The all metal angle valve is for the SRS RGA 100 (which I unboxed and inspected; it looks good) to reduce any contamination. The composite angle valve is for a leak checker. I tightened all 3 joints by hand unitl no copper was visible and there was a steel to steel connection all the way around.

I have now set up the particle counter and a NUC to run the software I made to view and display the current data coming from the counter. We will however need to continue to turn the counter back on to keep counting if it stops running. We should be able to tell via the interface i made if it stopped (past 6 hours or other plots are blank).
Anyone on the subnet can access this page if it is running, see the pdf's below for how it should look.

Access particle counter page: http://192.168.56.1:8050

Access the particle counter data page: http://192.168.248.101/

      (Both are only available on the subnet)

Notes:

• Hitting Stop on the top left of the screen stops the entire server. ONLY Press this if you intend to turn off the server completely!
• To restart the server please go to the NUC machine in the EE lab, find a terminal, and run
  • open VScode and a PowerShell terminal (preferred for now)
    • python particle_server.py
  • Open a PowerShell terminal on Windows (may give errors)
    • cd Documents/particle_bot
    • python particle_server.py
• To switch to light theme please go into particle_server.py and change dark_theme to False
  • monitor = ParticleMonitor("192.168.248.101", dark_theme=False)
• If you think new data is available and the server hasn't refreshed yet, please hit refresh at the top right corner.
  • The tab you have open will say "updating" once this is finished you may need to refresh the page for new data manually
• The Auto-Update Interval can be changed accordingly. It adjusts how frequently the data thread pulls new data from the particle counter
  • It auto-sets to 1 minute when the whole server is restarted so please set it back to 5 minutes if you need to restart
• There are Mattermost notifications if particles exceed a set threshold but this must still be tested further.
• To adjust alarm values go to particle_server.py and adjust the values
  • monitor.alarm_03_um = 40
  • monitor.alarm_05_um = 40
  • monitor.alarm_1_um =  40

I installed the Up-to-air Valve (F0275XVALVE) on the "input" side of the Laser Filter Cavity (LFC) on a 6" to 2.75" reducer flange. I tightened the bolts to ~20 Nm but needed to use a basic wrench while tightening the bolts.

[Jeff, Alex, Daniel]

We placed the partially assembled 6" 6 Way Cross on the 6" flange of the 8" to 6" reducer tee of the Laser Filter Cavity (LFC). The 2" long screws have to go into the 6 way cross, so we put them through the rotatable flange on the reducer tee. The four 2" long screws that go over the body of the tee must be inserted into the tee's flange alone, rotated into place, then inserted into the 6 way cross. We then added the remaining screws and plate nuts. The 80/20 structure got in the way so I partially disassembled it and instead and supporting the tee with a small jack and some viton. I tightened the screws to 34 Nm until the copper gasket wasn't visible.

We then added two 6" to 2.75" zero length reducer flanges, one on the "input" side of the LFC (a non-rotatable flange for the 6 way cross) and one on the open end of the table away from the power distribution. I need to tighten these screws and will then add the subcomponents that go on the 2.75" side. The subcomponent on the open end of the table is a 2.75" tee that I sourced from the holometer. I need to separate it from the ion pump and valve.

Jeff and I made sure to orient the 6" to 2.75" zero length reducer flanges so that everything looks vertical/horizontal instead of askew.

[Jeff, Daniel]

We assembled a 6" to 2.75" zero length reducer flange on a non-rotatable flange of the 6" 6 way cross for the Laser Filter Cavity (LFC). The 6 way cross has 3 rotatable flanges and 3 non-rotatable flanges. Opposite sides have one of each.

After tightening the bolts to 34 Nm and seeing no copper gasket, we added the Agilent FRG702 Pressure Gauge. The magnet was 0.6" below the main body of the gauge before moving it up to fit the screws. We added the screws and tightened as hard as I could with the ~8" long wrench. The copper gasket wasn't visible. We tried to move the magnet down to its original location but could only get it 0.45" in down and unsecured.

We tried to add the 6 way cross to the 8" to 6" reducer tee but it was too heavy for 2 people if one person help up the rotatable flange on the tee. We'll need a 3rd person for this job.

Now that we have an operational timing circuit, we can assemble the main chassis of the Babbage cymac and hopefully not neet to poke around inside anymore. The lid does not fit on top due to the bulk of the pcie extension cables, so Daniel is going to cut a hole in the top and the cables will poke out.

Notes from assembly:

- The standoff holes on the General Standards ADC and DAC are a bit small for the 6-32 standoffs. However the standoffs are nylon and can be forced through.

- The angle brackets for holding the Adnacom backplane in place are not the correct size. Daniel made something work but it required stacking 7 washers to make a spacer.

- The main headache of this assembly are the pcie extension cables. Most of the cables Todd and I can find on Amazon are quite bulky, and there is very little room to fit them between the PCBs and the walls of the chassis. I ordered a few types and tried a few of Todd's, and they are all bulky. Todd has some old ones that work well but he can't find them sold online anymore. Instead of continuing to deal with this issue we are cutting a hole in the chassis.

Big todos on this project are to order the input/output PCBs (for whitening, dewhitening, and possibly other tasks?), and to push the software along so that we can begin communicating with the ADCs and DACs.

[Sander, Rodica Martin, Daniel]

Summary

We imaged the surfaces of our crystalline silicon optical substrates from Knight Optical using an optical profiler from 4D technology. The substrates are dusty, which significantly increases the surface RMS roughness. Removing the dust, either by cleaning with First Contact or by digitally masking the surface image to exlude dust, improves the RMS significantly. From these observations we conclude RMS roughness of all substrates is certainly < 0.3 nm and likely < 0.2 nm. Given these numbers and estimated scatter losses due to this roughness (see post 12119), we believe no further polishing is neccesary.

Measurement procedure

We unpackaged the substrates, handling them either by suspending them on some lens tissue and holding the lens tissue, or by holding the barrel with gloved fingers. We then aligned the optic visually with the center of the imaging aperture of the profiler. We then focussed the image using the profiler's software and manual focussing controls. The images captured were 3.547 mm by 4.255 mm, or 2056 px by 2464 px. An average of 32 images was taken. We saved .4D data files for all measurements. We marked the packaging of each subtrate that we measured with a serial number. According to Rodica the profiler software has some functionality to remove artefacts such as those from dust and fringes, but this removal is incomplete as these artefacts still show up in the image and contribute to the RMS.

Results

Spoked Circular and Octagonal (SC-2in/SO-2in)

The spoked optics are the cleanest substrates out of all measured. We managed to image unmasked sections of some of these without any dust present, giving RMS < 0.18 nm. These images still have fringe artefacts so this is to be taken as an upper bound on the RMS.

Unspoked Circular and Octagonal (UC-1in/UO-1in)

The uspoked optics are very dusty. We cleaned one side of an UO-1in substrate with First Contact (peeling off 35 min after application, Rodica says this reduces residue left after peeling off compared to waiting longer) and compared to the other uncleaned side of the optic. This uncleaned side has RMS = 0.675 nm, the cleaned side had RMS = 0.194 nm. Applying a digital mask, excluding parts of the image with dust, reduced the RMS of the dirty side to 0.165 nm.

Unspoked Wedged Circular (UCW-1.5in)

These substrates are quite dusty (like the other unspoked optics, they were all part of the same order, so this makes sense). Notable arc-shaped scratches were seen on both sides of the optics, presumably from the procedure that produces the wedge. The wedge was observable by focussing the profiler on one side and observing the changed fringe pattern once the substrate was flipped over. Images of a substrate with lots of scratches and some dust and fringe artefacts had RMS = 0.298 nm and RMS = 0.274 nm. Given the RMS improvement from cleaning dust and masking seen from other substrates, I would estimate the RMS is actually < 0.2 nm.

Data for all measurement is in the attached spreadsheet (will upload to the wiki, we might want to add more data into it), as well as some screenshots of the measurements.

We have one working clock circuit for a cymac main chassis. We have two more PCBs which are both slightly incomplete.

Today I went to Downs and Todd flashed our 3 arduino nanos with the software outlined in LIGO-E2300449. The steps look simple enough, but since Todd had already done this for his Arduinos it was as simple as connecting to his computer and hitting upload.

I then returned to bridge where I tested one of our clock circuits. I learned that the ATX power supply only outputs a voltage if the large ATX connector is plugged in, hence the PCIe backplane resting on the anti-static bag in the photo.

The one complete clock PCB that we have works. We have two more PCBs from Todd, but they are each missing a component or two. One is missing two buffers (center and marked by orange) and the other is missing an RF relay (look top, K1)  Perhaps I will work with Todd to complete them.

It is also possible that we don't need the relay, which appears from the schematic to be related to the external input.

[Jeff, Sander, Alex, Daniel]

I cleaned the inside of the 5" long, 10" to 8" nipple. We then slid the input vacuum cube on Laser Filter Cavity (LFC) toward the 5 in Long 8 in CF flange bellows. We stuck screws through the nipple and eventually through the bellows as well, getting them somewhat tight with plate nuts. We then further slid the input vacuum cube into place and bolted it down. Jeff and I then removed the screws on the top half of the connection and loosened the others so that we can drop in the copper gasket. The gasket was not properly seated intially, so Jeff pushed the gasket up and away and the gasket dropped into place. We reattached the screws and tightened all the screws. I still need to tighten the screws to ~23 Nm. Waiting a bit for the bellows to plastically deform back might make this easier.

I thought we would want to use the engine hoist, but we decided to just push the cube. We did make some metal to metal contact, but I think the knife edge is ok. I briefly inspected the window attached to the output cube since it is fragile, and it looked fine. I have no real reason to expect damage. I'll install the input window last.

I measured the length from the center to center of the vacuum cubes (around where the mirrors will go), and it is 44 in (1.12 in), almost exactly what Ian designed.

See attached photo.