 Mon Jul 10 13:23:23 2023, Aiden, Update, VAC, VAC System Heating Update
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Checked on the system today.
The flange on the turbo pump has reached an equilibrium temperature of 87 degC when set at 150 degC. While
the main body of the chamber has reached an equilibrium temperature of 142 degC.
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Thu Jul 13 14:56:43 2023, Aiden, Update, VAC, VAC System Heating Update
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Checked on the vacuum system today to change the PID controls back to their default values in order to try and get the temperature of the cross in
front of the turbo pump higher. Currently it is sitting at 90 degC before changing the controls. While the main body is at 146 degC.
Will update
again tomorrow on new equilibrium with the default PID settings.
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Fri Jul 14 14:37:25 2023, Aiden, Update, VAC, VAC System Heating Update
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Checked on the vacuum system and it looks like it will either need to be increased in temperature or baked for a longer time. The main body is at 146C
while the cross is at 91C.
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Mon Jul 17 13:50:41 2023, Aiden, Update, VAC, VAC System Heating Update
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Started to cool down the chamber today. Final temperature readings of the chamber were 146C and 91C for the body and cross respectively.
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Mon Jul 17 14:01:41 2023, Aiden, Update, VAC, VAC System Heating Update 
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The insulation on the lid of the vacuum chamber has some discoloration and it may be wise to place a sensor closer to this spot in future bakes.
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Thu Jul 20 18:03:19 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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Took another set of RGA data after the second bake has cooled down to 27 degC.
Just by visual comparison to the other graphs, the HC levels
of the chamber has gone down further. I will soon overlay the data for an easier comparison.
I also reinstalled the full range gauge above
the RGA line. It is still adjusting itself downwards so I will have to check again to get an accurate measurement of the pressure.
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Mon Jul 24 14:55:53 2023, Jon, Update, VAC, Removed extension power cable
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I removed the extension cable that was powering the leftmost heater controller, since there is no bake currently happening. It is currently powering the
LED over the electronics bench, and can be removed if needed. I will be ordering more extension cords to permanentize our setups. |
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Fri Jul 28 13:46:17 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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Took some more data to look at the HC count. Initial data was from leaving the Argon leak closed and then left it open for 15 minutes and then took
data for the open scenario. Attached are the graphs for these where attachment 1 is the closed scenario and attachment 2 is the open scenario.
From
these graphs it looks like the signal-noise ratio of our calibration line is poor with the ratio between these two being 1.3. This means that the calibrated |
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Tue Aug 1 12:10:03 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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Dr. Richardson and I took off the insulation on the lid again to add more insulation in-between the heater tape folds in addition to what was added
on top of the tape after discovering discoloration. Also cleaned the lid with IPA wipes.
Also took more RGA data, one with the leak closed
and one with the leak open. The graphs below this show that the SNR is improving with the ratio now looking to be around 3. The chamber is still too dirty |
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Wed Aug 2 17:02:38 2023, Aiden, Update, VAC, VAC System Heating Update
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Moved the temperature sensor on the PID controller to one of the switch backs on the lid.
Also started the next bake with both PID controllers
set to 150 degC. When leaving the temperature sensors above the chamber read 119 C and 83 C. These sensors are on the chamber wall and flange in front
of the turbo pump respectively.
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Thu Aug 3 16:00:25 2023, Aiden, Update, VAC, VAC System Heating Update
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Check on the temperature of the bake today to see the equilibrium temperatures. With both of the PID controllers set to 150 C, the temperature sensors for
the wall of the chamber and the flange in front of the turbo pump read: 125 C and 90 C respectively. At these temperatures the bake would need to last
at least a week unless the temperature were to be increased. |
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Thu Aug 3 17:47:51 2023, Aiden, Update, VAC, VAC Heating System Update
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Did some further testing to determine if it was within reason to increase the temperature of the chamber. I used a thermometer and pulled back some
insulation to test many points on the chamber. Mainly focused on the barrel and the bottom lid of the chamber to see if it was possible to increase the
temperature of just the PID controller that is powering the bottom half of the chamber.
Found that the barrel of the chamber seems to be hotter |
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Fri Aug 4 15:21:33 2023, Aiden, Update, VAC, VAC System Heating Update
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Checked on Bake 3 today and the temperature sensors read 126 C and 91 C for the chamber barrel and turbo pump flange respectively. These were reached while
the PID controllers were set to 150 C. |
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Tue Aug 8 15:31:26 2023, Aiden, Update, VAC, VAC Heating System Update 10x
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Vacuum Chamber equilibrium temperature for bake 3 are 126 C and 88 C for the chamber wall and turbo pump flange respectively. There were reached with
the PID controllers both being set to 150 C.
Also noticed some discoloration around the port insulation. It could be burned from being exposed
to the heater tape directly without insulation or it could be that the insulation, which looks much different, is depositing something around the ports.
The |
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Thu Aug 10 14:36:00 2023, Aiden, Update, VAC, VAC System Heating Update
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Came in to install one of the Full range gauges. Checked the temperature first of the cross and it was reading 30 C. After installing the gauge above the
RGA line the controller was reading 2E-1 torr. Installed the other full range gauge to confirm this and it also read that pressure. There may be a leak
so I will let it sit for a bit and then perform a Helium leak test. |
 Thu Aug 10 15:10:12 2023, Jon, Update, VAC, VAC System Heating Update
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I shut down the turbo pump since this is evidently a large leak. We CANNOT turn on the RGA for leak checking with the pressure above 1E-5 Torr.
I think
we will have to manually inspect it. The most likely cause would be that the Viton seal around the lid overheated and failed.
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Thu Aug 10 18:32:39 2023, Aiden, Update, VAC, VAC System Heating Update
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[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 |
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Fri Aug 11 18:32:00 2023, Aiden, Update, VAC, VAC System Heating Update 11x
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[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 |
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Tue Aug 15 16:04:23 2023, Aiden, Update, VAC, VAC Heating System Update 6x
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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.
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Thu Aug 17 15:02:44 2023, Aiden, Update, VAC, VAC Heating System Update 11x
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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 |
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Thu Aug 17 15:18:48 2023, Aiden, Update, VAC, VAC Heating System Update
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Relocated the PID controllers so that the heating tape could be plugged in. In the picture the left one controls the top half of the chamber along with
the RGA line and has its sensor on the lid near a fold. The right one controls the bottom half along with the turbo pump line and the bypass line and has
its sensor on the barrel of the chamber. The chamber is almost ready to bake again and just needs to have the full range gauges and RGA electronics box |
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Mon Aug 21 17:13:25 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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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 |
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Mon Aug 28 14:43:50 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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The PID controllers were turned off on Friday and the chamber was left to cool over the weekend. Just took data and it looks like signal to noise ratio
is pretty bad again. I do not know if this means we need a hotter bake or if the chamber needs some more time to cool down. I will overlay this data and
make sure to take a second set a bit later to compare. Some good news though is that the chamber has reached a pressure below 10e-8 torr with the full |
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Tue Aug 29 19:09:21 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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Here are some more plots with the RGA data take August 29. It seems that more pumping time has led to the HC levels being dramatically reduced compared
to only a day ago. The pressure also rises significantly when turning on the RGA filament and it doe not go back down to the pressure before turning it
on while the RGA is still running. The pressure after I left was 6.86 e-8 torr. |
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Thu Aug 31 12:56:29 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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Took some more RGA data to see if the HC levels have further declined since bake 4 and it seems that it has started to plateau with August 29 160.7 e-10
Torrl/s and August 31 giving 158.4 e-10 Torrl/s. The pressure of the chamber before taking data was 5.1 e-8 Torr. I have attached an overlay of the data
from August 29 and August 31. It seems that the extra two days has not noticeably changed the data and another bake will most likely be needed to meet |
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Fri Sep 1 19:21:19 2023, Aiden, Update, VAC, VAC System Heating Update
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Started bake 5 today. This will hopefully be a longer and hotter bake with it lasting 6-7 days at around 150 C. The pressure in the chamber before removing
the full range gauge and RGA box was 5.01 e-8 torr. The Argon leak was also left open for this bake to hopefully get rid of particulates on it. I also
put the heater tape I removed last time back onto the RGA cross. This made the heating up process take much longer as I had to not increase too much or |
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Fri Sep 8 16:10:43 2023, Aiden, Update, VAC, VAC System Heating Update
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Turned off the PID controllers to let the chamber cool down. Final temperatures for the RGA cross and Turbo pump cross were 113 C and 80 C respectively.
The system should be cool enough to start taking measurements on Monday. |
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Mon Sep 11 16:02:42 2023, Aiden, Update, VAC, VAC System Heating Update
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The chamber has cooled down from bake 5 and I took the first set of data. The pressure measured during the RGA measurements reached 9.98 e-8 torr. The data
shows that the chamber got dirtier, however this has been the case for every first scan after a bake so I assume there are still some more hydrocarbons
to be vacuumed out and that the second scan will most likely give a better idea of where the chamber is at. After turning off the RGA the pressure immediately |
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Fri Sep 15 17:33:35 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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Took some more RGA data and see that the chamber has gotten much cleaner since monday. Next step would be another bake with some focus around heating the
RGA filament more. The pressure in the chamber before testing was 5.32 e-8 torr. |
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Wed Oct 11 20:47:11 2023, Jon, Update, VAC, Vacuum upgrade begins
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[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 |
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Thu Oct 12 12:11:10 2023, Aiden, Update, VAC, Vacuum chamber Helium leak test
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[Aiden, Tyler, Peter, Jon]
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.
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Thu Oct 19 11:41:04 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update 6x
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[Aiden, Tyler, Mohak]
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 |
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Thu Oct 26 13:00:45 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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Bake 6 was turned off on Monday. Tooke RGA data today and have posted the data below. The pressure of the chamber after taking data was 3.22 e-8 Torr. The
chamber HC levels are still not low enough but I feel with more pumping it will go down as the RGA scan was still slowly going down during the data taking. |
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Fri Oct 27 15:16:31 2023, Aiden, Update, VAC, Vacuum Leak Test
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Leak tested the worst flanges on the chamber after moving it and after bake 6. The 6 inch flange connected to the 8 inch reducing nipple is now leaking
at 1.5 e-9, previously at 4 e-9. The 8 inch flange connected to the turbo pump is now leaking at 1.9 e-9, previously at 3 e-9. This means that the baking
most likely improved the seals on these flanges and a hotter bake might fix the leaks for good. |
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Mon Oct 30 08:42:22 2023, Jon, Update, VAC, Vacuum Leak Test
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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).
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Tue Oct 31 19:46:35 2023, Aiden, Update, VAC, VAC System Heating Update
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Started bake 7 on Monday but found issues with the heating as the cross in front of the RGA got way too hot too quickly. This resulted in shutdowns of the
heater tape while I could still only set the main PID controller for the lid to 75C. Tuesday I moved the PID controller sensors to be on the cross in front
of the RGA and on the Reducing nipple. I then placed the alarm sensors onto the lid of the chamber and the barrel. This should hopefully prevent excessive |
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Wed Nov 1 20:22:07 2023, Aiden, Update, VAC, VAC System Heating Update
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Raised the PID controller temperature to 105C today as at that temperature the lid and the barrel temperature sensors were reading around 120C. I will check
again tomorrow to see if there is any room for increase after equilibrium. |
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Thu Nov 9 13:48:47 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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After bake 7 was stopped on Wednesday morning (11,8,2023), I took RGA data of the chamber to compare to a later scan that will be done on Monday to make
sure the chamber has reached its lowest pressure. Below are the graphs. |
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Fri Nov 10 08:32:34 2023, Jon, Update, VAC, RGA experiments
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I ran a 3-minute degas cycle of the RGA filament for the first time yesterday (in this process, the filament gets very hot in
order to "boil off" settled particulate). I was surprised to see the pressure (of not just the RGA volume, but also
the main volume) rise from 2e-8 to 5e-6 torr.
This observation, |
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Mon Nov 13 11:07:50 2023, Tyler, Update, VAC, RTD Analysis
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After initial analysis from last week on a single RTD, I then extended to looking at all 8 in series with R_ref (set to 1 kOhm). Shown below are the
edge cases for the setup:
RTDs are all at ambient lab temperature. This would correspond to a minimum resistance value.
RTDs all read out 400 C. This gives the maximum resistance value.
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Tue Nov 14 17:21:40 2023, Jon, Update, VAC, RGA best practices
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As a follow up ELOG 261, I have received advice from one of the vacuum experts at LIGO Hanford
on best practices for our RGA:
For future RGA degassing, definitely keep the main volume isolated, since it |
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Wed Nov 15 21:52:33 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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| Took RGA data before running the degas mode. Made sure to close off the main volume before running the degas. And left the filament on. |
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Thu Nov 16 19:32:31 2023, Aiden, Update, VAC, VAC HC Levels Update
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Took some more RGA data today and overlaid it with data taken from October 19. I added a red line that symbolizes where all amu peaks above 44 need to be
bellow as well as a black square around the 44th amu peak. The chamber is very close to being meeting LIGO's vacuum chamber standards. |
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Mon Nov 20 20:37:45 2023, Aiden, Update, VAC, Clean and Bake Batch 20
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[Aiden, Luis]
Started to clean and bake the macor parts for the FROSTI reflector. Per LIGO documentation cleaned the macor in liquinox for 10 minutes and
put them in the oven at 200 degC for 24 hours. |
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Mon Nov 20 20:45:16 2023, Aiden, Update, VAC, Leak Test
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[Aiden, Luis]
Tested every weld and flange to find leaks. Only found that the flange on the turbo pump and reducing nipple was still at 2e-9
torr on the leak. The chamber still rose in pressure when the two gate valves were closed but no noticeable leak could be found on the lid or welds. |
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Wed Nov 29 21:13:32 2023, Aiden, Update, VAC, VAC System Heating Update
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Started Bake 8 today. Set the PID controllers to 120 C and will check in the morning for equilibrium temperatures for the lid and chamber wall. The chamber
pressure was 2.13 e-8 torr before taking off the full range gauges.
After the bake is done on Saturday it will be cooled down and RGA data will
be taken to measure the out gassing rate of the stainless steel fasteners inside the chamber. Then on Tuesday we will plan to vent and open the chamber |
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Thu Nov 30 13:58:18 2023, Aiden, Update, VAC, VAC System Heating Update
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[Aiden]
Came into the lab in the morning to check on the chamber heating. I decided to set the PID controllers to 110C rather than 120C as the chamber
lid and wall were reading near 140C. With the PID controllers at 110C the chamber lid and wall now read 126C and 132C. Currently the PID controllers are
placed on the cross in front of the RGA and the reducing nipple in front of the turbo pump. I believe this is a good equilibrium and will leave the tape |
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Sat Dec 2 18:10:23 2023, Aiden, Update, VAC, VAC System Heating Update
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[Aiden]
Turned off the heating tape today in anticipation to take more RGA data on Sunday or Monday morning before the meeting. |
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Mon Dec 4 11:19:50 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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[Aiden]
Took some RGA data of the chamber after it has been cooling down. I do not believe that this data accurately shows the HC levels in the chamber
as the pressure is still above where it was at before the bake and was still falling. I believe more time is needed to let the pressure fall and for the
RGA filament to remain on to return to a point where the data can be trusted. |
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Thu Dec 7 12:42:42 2023, Aiden, Update, VAC, Vacuum Chamber Baking Update
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After leaving the RGA on for a few days the chamber has settled at 2.01 e-8 torr. I also have good news that the chamber looks to be even cleaner as the
HC levels are now the lowest they have been being at 26 e-10 Torr l/s. |