FLIR: After some adjustments, the plot generated from the FLIR measurements look much more symmetric (see attachment). There are more included grid points, which smooths out the curve as compared to last week.

Red Pitaya: It looks like a new OS update was released for the RP, which includes a new Python API (was previously only available in C). I'm going to try and update the one we have currently running in lab.

By 5:30 pm Friday, the pressure had reached 8.6e-8 torr and was continuing to fall. So it seems we are OK to proceed with permanentizing this configuration (cable routing, heater tape reinstallation).

cleaning cleanroom and particle count

• 3:16 pm: started particle count.

  NOTE: we are not within the ISO class 5 standard for any size ranges in zone 3. ~6000 above limit in 0.3 u, ~2000 above in 0.5, ~200 above in 1.0

  • zone 3:
    • 0.3 u: 16,711
    • 0.5 u: 5612
    • 1.0 u: 1039
• zone 4:
  • 0.3 u: 6817
  • 0.5 u: 2369
  • 1.0 u: 249
• 3:35 pm: began surface check and wipedown, including softwalls
• 3:50 pm: started vacuuming the floor
• 4:00 pm: finished vacuuming the floor
• 4:01 pm: started mopping the floor
• 4:06 pm: finished mopping the floor
• 4:07 pm: started cleaning the buckets
• 4:08 pm: started mopping with IPA wipes
• 4:14 pm: finished mopping with IPA wipes
• 4:15 pm: changed sticky floor mats
• 4:18 pm: started particle count
  • zone 3:
    • 0.3 u: 23,113
    • 0.5 u: 9686
    • 1.0 u: 1371
• zone 4:
  • 0.3 u: 7191
  • 0.5 u: 2951
  • 1.0 u: 290

Took some RGA data when we came into the room. The pressure of the chamber was 8.63e-8 Torr before turning on the RGA filament. We saw the usual spike in pressure when the filament was initially turned on. Took some data and saw that the chamber was definitely dirtier since the vacuum upgrade. See figures below.

Put the heater tape back onto the section that was removed. We may need to rearrange the heater tape again as there was not much heater tape to go around the upgraded section. We also tried to get some of the extra insulation around this section and we able to get some on around the 6-8 inch reducer.

We then took off the electronics for the gauges and the RGA, added the new extension cords to the PID controllers, and then started bake 6 which will go to 120 degC and stay that way until most likely Monday. The pressure before starting the bake was 8.28e-8 Torr.

Continued tightening bolts on the turbo pump and 6"-8" reducer to reduce the leak. The final leak test values for the turbo pump flange was 3.0 e-9 and the other 6"-8" reducer flange was 4.0 e-9.

We will continue to let it pump down as the screws could not be tightened anymore. Looks like new gaskets will be needed to reduce the leaking on these flanges.

[Jon, Tyler, Aiden, Peter]

Upgrade of the UHV system to a larger turbo pump began today. After obtaining a final RGA scan in the old configuration (Aiden to post), we vented all three volumes and proceeded to disassemble the 4.5"-diameter pump line. We completed installation of the new 6"-diameter pump line to the point where the new turbo pump will attach. This includes a 6" manual gate valve, 6"/2.75" reducing cross, and 6"/8" conical reducing nipple, as pictured below. Strain relief was also installed due to the longer length and greater weight of the new fittings.

Tomorrow we will continue with attaching the Varian TV 551 pump and perform a pump-down test. If this pump is confirmed to be operable, then we will relocate the entire system ~18" closer to the middle of the table and permanentize the setup.

Today's CyMAC work:
• Finished assembling external power supply cable for the timing chassis (see attached image)
• Also did some debugging of AA and AI chassis re: power issues. After testing voltages at various test points on the power regulator board (TP1-TP6) in the AA chassis, it seems like it's the source of the problem. Used bench DC power supply to test, running 15V, and the correct voltage is coming in to the board but something significantly smaller is being output. We're also getting unexpected negative signs on voltage at certain test points, with leads in correct positions
• Upon further examination, it looks like the lights on the filter boards are actually turning on (in both the AA and AI chassis), though it's only 2/4 lights on each board and they are very faint
• Corrected DC on/off switch spade lug orientation in AI chassis.
• Tested AI chassis power regulator board to see if the problem was the same, and found again that voltage coming in was correct, and voltage going out was not.
• In case of interest in exact numbers, results were as follows:
  • Voltage difference between TP1(+Vin) and TP6(-Vin) is ~30V
  • Voltage difference between grounded chassis wall and TP1 (+Vin) is ~15V
  • Voltage difference between grounded chassis wall and TP6(-Vin) is ~-15 V
  • voltage difference between TP2(+Vout) and TP5(-Vout) is ~3V
  • Voltage difference between TP3 (gnd) and TP2(+Vout) is -0.065V
  • Voltage difference between TP5(-Vout) and ground is ~3V

cleaning cleanroom and particle count

• 10:06 am: ran zero count test on particle counter
• 10:07 am: started particle count
  • zone 3:
    • 0.3 u: 2203
    • 0.5 u: 831
    • 1.0 u: 540
• zone 4:
  • 0.3 u: 374
  • 0.5 u: 124
  • 1.0 u: 124
• 10:25 am: began surface check and wipedown
• 10:34 am: started vacuuming the floor
• 10:44 am: finished vacuuming the floor
• 10:45 am: started mopping the floor
• 10:49 am: finished mopping the floor
• 10:50 am: started cleaning the buckets
• 10:57 am: started mopping with IPA wipes
• 11:01 am: finished mopping with IPA wipes
• 11:02 am: changed sticky floor mats
• 11:03 am: started particle count
  • zone 3:
    • 0.3 u: 2535
    • 0.5 u: 374
    • 1.0 u: 166
• zone 4:
  • 0.3 u: 581
  • 0.5 u: 41
  • 1.0 u: 0

Came in to take RGA data and found the turbo pump drawing .38 Amps. This was much higher than what it was on Friday. I investigated and found that the breaker had flipped controlling the power strip that the scroll pump was on. The scroll pump was thus not running. I flipped the breaker back and turned the scroll pump back on. I do not know if this will be a reoccurring problem as this has happened before, or if this was due to the storm. Either way the scroll pump is running and the turbo pump is now only drawing .18 Amps at 31 C.

Below are the graphs for the RGA scan that I took before starting bake 4. I have not overlaid them yet so the first one is for Argon leak closed and the second is the Argon leak open. It seems that the chamber had gotten dirtier since the leak and there is still a lot of water left in the chamber. I assume the water will go away after the low temp bake but the HC count may not go down without a longer baker. I also measured the pressure before starting the bake and it was 4.16 e-7 and 3.31 e-7 torr for t he main body volume and RGA volume respectively.

When starting the bake I noticed that the temperature sensor placed on the cross in the RGA volume was reading 40 C hotter that what the PID controller was reading for the lid. I had to remove some of the heater tape from the cross as it was way too hot compared to the lid. After removing the second strip across the cross it is still much hotter than most parts due to it being such a small part compared to the large lid. I hope that after a little bit of equilibration time that the difference between these numbers will go down. Both PID controllers were set to 120 C. The RGA cross was reading 130 C and the Turbo pump cross was reading 76 C.

Put the heating tape back on and made sure to have 4 coils around the barrel of the chamber. To make this happen I did not put any heater tape on the ports but made sure to place some of the heater no more than 1 inch away from the ports. Also re-placed some of the heating sensors. For the PID controllers there is one sensor placed on the lid and one sensor placed on the barrel. For the temperature alarms one sensor was placed near the flange of the turbo pump and another placed on the cross in the RGA line. Note that all four of these sensors were placed under the heating tape compared to the last few bakes where they were on top.

The insulation was also put back on and now the chamber should be ready for a low temperature bake after some RGA data is taken before for comparison.

Pulled off the rest of the heater tape along with the aluminum tape left behind. The aluminum tape adhesive left behind a ton of junk on the walls of the chamber. This is probably due to excessive heating. In order to get the adhesive off I sprayed a vector alpha wipe with acetone and wiped down the walls. This took a lot of acetone to get it off.

When removing some of the aluminum tape I noticed small sections that seemed to have been melted to the silicone part of the heater tape and would have been damaging to try and forcefully remove it.

The heater tape is now ready to be put on again but now with the start of the tape placed on the other side so that the PID controllers can be placed on the shelf above the chamber and be seen outside of the curtain.

[Dr. Richardson, Aiden] Large Update

Removed most of the insulation on the chamber in order to pull back some of the heater tape to get to the flange connecting the bypass line to the valve under the RGA line. Most of the heater tape on the bottom half of the chamber was pulled off and the rest will need to be removed as well in order to place the start of the heater tape on the barrel of the chamber rather than one of the flanges.

Engaged the valve under the RGA line to prevent it from getting more contaminated. Turned off the turbo pump. Turned off the scroll pump. Let the turbo pump sit for a few minutes to let the fans stop. Then leaked the turbo pump volume by turning the knob slowly on top of the turbo. Then proceeded to unscrew the bypass line after done leaking the volume. Replaced the copper gasket and then proceeded to screw it on while maintaining a circular path to ensure equal pressure on the gasket. BEWARE THAT REUSING SILVER PLATED SCREWS HAS A HIGH CHANCE OF STRIPPING THE SCREW AND WILL RESULT IN A LOT OF WORK TO GET THEM OFF. IT IS RECOMMENDED TO USE NEW SILVER SCREWS. HOWEVER WE HAVE NONE LEFT SO DO NOT TRY TO REUSE ANY SCREWS UNTIL WE HAVE SPARES. We were able to use the remaining two spare screws to tighten the flange to a point where it will not tighten anymore.

Then the lid was removed in order to inspect the inside of the chamber and the Viton O-Ring. The chamber had no physical damage and the viton had some visual damage that may correlate to the failure observed during bake 3. Note that some metal chips were found inside of the o-ring groove and needed to be removed. We changed out the o-ring for a new one and placed the old one inside of an anti static bag labeled "Viton O-Ring". Put the lid back on after inspecting for damage and put the bolts on hand tightened. Started to pump down again by turning on the scroll pump first until full range gauge 1 read below 1 torr and then began to turbo pump. The turbo pump was running for 1.5 hours until it plateaued around 3e-4 torr. We then realized the bolts on the lid needed to be tightened more with a wrench. After further tightening the pressure quickly dropped to 6e-6 torr. In the future the bolts should be tightened with a wrench from the begining.

Then proceeded to Helium leak test every weld, flange, and valve. Two of the flanges needed a little more tightening such as the 2 6" flanges. Other than that the only noticeable leak was from the flange just fixed today, however the leak is 10 times less than how it was yesterday and will most likely not hold the chamber back from reaching low 10e-8 torr pressures.

[Dr. Richardson, Aiden]

DO NOT TOUCH ANY VALVES ON THE CHAMBER. THERE IS A PRESSURE DIFFERENTIAL BETWEEN THE RGA LINE, TURBO PUMP LINE AND THE MAIN VOLUME. THE TURBO PUMP WILL BE DESTROYED IF OPENED.

Closed the valves to the turbo pump line and RGA line. Turned the turbo pump back on and saw that the pressure in the RGA Line and Turbo pump line was going down so there was no large leak within that line or with the valves as the main body pressure stayed constant. Then raised the pressure of the main body of the chamber as we suspect the viton o-ring has failed and needs to be changed. The bolts to the lid of the chamber were also removed but the lid was left on.

Then performed a helium leak test on the section of the system that was under vacuum. We found two flanges that had small but significant leaks compared to the others in the lines. The flange connecting the full range gauge to the cross and the flange connecting the stainless steel tube to the valve under the cross. These showed large spikes when sprayed with helium and were then tightened to hopefully fix it. After tightening, the flange under the full range gauge was fixed as the bolts were pretty loose and tightening reduced any spike seen on leak test. The other flange on the SS tube could not be fixed with tightening and it still shows signs of helium leaking through. This flange will need to have its gasket changed to fix this leak. Then left the system where it is in the picture for further changes tomorrow August 11. Again, DO NOT TOUCH THE VALVES ON THE RGA LINE AND TURBO PUMP LINE AS THERE IS A PRESSURE DIFFERENTIAL AND IT WILL DESTROY THE TURBO PUMP IF OPENED.

Note: We also found that the pump under the table had flipped the breaker and needed to be turned back on. This may be something to look into.

I delivered new NEMA 5-15 (120V / 15 A) power cables to the lab for the following items:

• WS2 (cleanroom) cart - 10ft cable
• Electronics workbench overhead LED - 10ft cable
• Both PI heater controller sets - (2) 6ft cables

I installed the new cables on the WS2 cart and the workbench myself, and left the two 6ft cables (as pictured below) for Aiden to install on the PID controllers after the current bake is finished.