 Mon Jul 15 09:36:44 2024, Liu, Update, Interferometer Simulations, ETM Profile Optimization for FROSTI 
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This is to optimize the FROSTI heating profile for ETM, by minimizing the residual RMSE of the HR surface deformation after the beam size weighted curvature
is removed by the current RH. The parameters of the profile being explored are the location, width, and total power for the Gaussian Annulus. As shown
in the attached series of plots, the optimal location is 9.9 cm, with a width of 7.7 cm, and a total FROSTI power of 12.7 W (for 1 W of Gaussian beam absorption). |
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Sat Jul 13 15:09:04 2024, Luke, Update, General, Ring heater COMSL model update
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After the feedback from last meeting and Liu's help narrowing down what I should do to improve the model. I made some changes: First with Liu's help
I made the proportions of the test mass and ring heater much more reasonable and parametrized by constants. Second from Cao's paper "FROSTI Nonimaging
Reflector Design" Liu showed me what I should do to define the elliptical mirrors. Third during Friday's modeling/programming meeting walked me through |
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Thu Jul 11 15:53:39 2024, Luke, Update, VAC, RGA line upgrade
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[ Luke, Jon ]
Started work at 11:00
As mentioned in my previous post the RGA was not clearing the table because of a tilt in the cross. So I removed the 90 deg elbow, loosened the |
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Wed Jul 10 17:31:07 2024, Luke, Update, VAC, RGA line disassembly and upgrade
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[ Luke, Cynthia, Michael, Xuesi, Anthony ]
Started work around 12:45
We vented the chamber first and once it reached atmospheric pressure we started taking apart the RGA line. |
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Mon Jul 8 17:01:45 2024, Shane, Update, CDS, New CyMAC internal layout
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[Jon, Shane]
Internal layout of CyMAC has been updated (labeled image attached) to accommodate the replacement of the two ribbon cables. Looking down
on the chassis from the front, and going from left to right, the new placement is as follows: BIO card, DAC adapter board, ADC adapter board, DAC card,
ADC card. NOTE: As part of ADC-DAC loopback testing, we're disconnecting from the FROSTI readout chassis and using the cables to connect directly from |
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Mon Jul 8 12:26:10 2024, Michael, Update, Interferometer Simulations, Minimizing Astigmatic Effects in the SRC of LIGO
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This is the first look and analysis of the effects of astigmatism in the aLIGO optical layout which can lead to mode mismatch and therefore increased losses
into higher order modes. Specifically I am currently looking at measuring the effect of changing the radii of curvature of the SRC mirrors https://docs.google.com/presentation/d/1qhIehqyNukg4g8S2fqfQZz83yr9aB76tEa6fn2J-TrM/edit?usp=sharing |
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Mon Jul 8 10:39:14 2024, Xuejun, Update, FLIR, Average Temperature Profile
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After taking data for each of the individual heater elements, I imported them into python and overlayed them to produce an average temperature profile.
I rotated the 7 of the elements to align with element 1's profile and averaged them out. By setting the range to 28C - 33C (this gave the best visibility
of the heating pattern) it gave the profile attached. |
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Fri Jul 5 14:23:13 2024, Liu, Update, Interferometer Simulations, Engineering drawings for straight edge heater element designs for FROSTI
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Step files and engineering drawings for the straight edge heater element designs have been created in COMSOL and SolidWorks. They are available in the group
Git
Repo. With those, we will initiate a discussion with the ceramics supplier for an estimate of the feasibility and benefits of the straight edge element |
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Fri Jul 5 14:12:32 2024, Liu, Update, Interferometer Simulations, CE BS Mechanical Resonances
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The butterfly and drumhead mechanical modes for the aLIGO BS were calculated in COMSOL. The resonant frequencies for the two acoustic modes are 2.45
kHz and 3.61 kHz, matching the results in reference
for instance.
For a quick projection for the resonant frequencies going from aLIGO to CE, the height and width of the BS are increased assuming |
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Fri Jul 5 13:17:44 2024, Liu, Update, Interferometer Simulations, Four-quadrant FROSTI-like RH for astigmatic thermal actuation for CE optics 7x
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In the CE corner layout design and down selection study, interferometer layouts with large incidence angles on some of the curved optics are being considered,
such as the folding mirrors in the "long crab". This however generates astigmatic beams upon reflection and results in mode mismatches in coupled cavities
that need to be mitigated. Astigmatic thermal actuation for the optics involved is thus essential. One way we are considering is to implement a FROSTI-like |
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Mon Jul 1 15:19:42 2024, Cynthia , Update, Interferometer Simulations, O4 and O5 mirror cavity scans with thermal effect
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Mon Jul 1 11:45:45 2024, Sid, Update, Interferometer Simulations,
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Progress update: Most of last week was spent getting set up with SIS, and learning how to do basic simulations. The goal for this week is to begin reproducing
the methodology from T2000338. I have begun with studying perturbations to mirror curvature and position in a simple FP cavity, but thus far have been
unable to get the same results. |
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Fri Jun 28 18:15:16 2024, Luke, Update, VAC, Vacuum chamber
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We will be configuring the RGA line to remove the spherical cube from the system. Currently our plan for the new design is to connect a 4.5" to 2.75"
Reducing Cross to the gate valve on the vacuum system. It will be orientated vertically with the turbo pump on top coming off the end will be a 90 deg
elbow. On the bottom there will be a 4.5" to 2.75" Zero length reducer attached to that will be a Tee on one side the pressure sensor and the other the |
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Fri Jun 28 10:43:13 2024, Xuejun, Update, Cleanroom, Frosti
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[Xuejun, Tyler]
We moved Frosti into the cleanroom and debugged it to make sure everything was working. One of the DB25 pins broke off at the connector
for element 1 so it needed to be recrimped. Element 6 short circuited but fixed with adjustment to the heater power pin position. We connected the power
and sensor connectors to the power box and recalibrated the RTD sensors.
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Thu Jun 27 13:42:02 2024, Shane, Update, Cleanroom, cleanroom 5 zone particle count measurement
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Here's today's 5 zone measurement of the cleanroom. We're above the limit by a bit in zone three (all three size ranges), likely as a result of the recent
work installing FROSTI, so it could probably use another focused cleaning. Everything else is below the limit. |
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Thu Jun 27 11:09:14 2024, Liu, Update, Scripts/Programs, Straight edge STEP files and ray loss analysis
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Drawings and CAD models of the straight-edge designs are exported, and are visualized in SOLIDWORKS. Two are attached. One is a single edge of the evenly
spaced polygon design with 16 edges, and the other is the 8x2 design, with two neighboring edges grouped together to replace the original single curved
heater.
For the straight edge design in COMSOL, ray power detectors were placed at the heater's front surface. The irradiance is shown in |
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Wed Jun 26 16:39:34 2024, Luke, Update, VAC, Vacuum chamber leak checking
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On Tuesday I had isolated the main volume and let it pump down over-night. Today, Wednesday, I checked it and it had only gone down by a small amount compared
to when I left it on Tuesday.
I then proceeded to tighten down the bolts attaching the tubo-pump to the zero-length reducer while it was under vacuum.
This caused the pressure to drop down a few orders of magnitude. |
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Thu Jun 20 18:01:11 2024, Jon, Infrastructure, Computers, New workstation ws3 in 1129
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I have repurposed a spare Intel NUC to serve as the first of two planned workstations in 1129. Today I set it up with a fresh installation of Debian 12.5,
assigned it the static IP address 192.168.1.15, and installed the LIGO CDS workstation packages. It is assigned the host name ws3.
Temporarily, the
mouse is borrowed from ws1 in 1119. We need to order another mouse as well as a 25-ft Ethernet cable for connecting the workstation to the 1129 switch, |
 Wed Jun 26 15:33:41 2024, Jon, Infrastructure, Computers, New workstation ws3 in 1129
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Set-up of the first CDS workstation for 1129, ws3, is complete and the machine is ready for use. The login credentials are the same as the other lab
machines.
All that now remains is to install a permanent cable tray for running the new Ethernet cables between the electronics rack and bench (they are |
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Tue Jun 25 17:19:42 2024, Luke, Update, VAC, Vacuum chamber leak checking
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Currently our main leak is in the RGA line. We found this by closing the gate valve from the main volume to see if which side was leaking more.
After
identifying this we are pumping down the main volume to see how low it can go the third attachment was taken at 4:16 6/25/24. Pumping started around 3:15.
We have not been able to find exactly which flange is leaking, but our guess is on the small blanks and where the cube attaches to the gate valve |
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Tue Jun 25 12:34:18 2024, Shane, Update, Cleanroom, cleanroom cleaning and particle count
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[Luke, Shane, Xuejun, Mohak, Michael, Tyler, Cynthia]
cleaning cleanroom and particle count
10:45 am: ran zero count test on particle counter
11:02 am: started particle count
zone 3: 0.3 u: 32840.5
u: 12471.0 u:332
zone 4: 0.3 u: 18290.5 u: 5811.0 u: 207
11:15 |
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Mon Jun 24 21:38:25 2024, Pooyan, Infrastructure, Computers, Computer server changes in 1119 and 1129
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[Jon, Pooyan, Tyler]
A few computer machine changes have been made. |
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Mon Jun 24 14:28:51 2024, Cynthia , Update, Interferometer Simulations, SIS cavity with thermal effect
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tried to run a cavity scan with thermal deformation and ring heater for ITM04 ETM08 (aLIGO mirrors). Not sure about the accuracy of the graph as there is
some commands that still need to verified. |
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Fri Jun 21 11:47:30 2024, Liu, Update, Scripts/Programs, COMSOL simulation on alternative straightened heater elements design 6x
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In the previous post, we saw that for the heater element design with straight
edges in replacement of the current eight-element ring-like design, it provides the similar Gaussian-like irradiance profiles, but with smaller power delivery
efficiencies, as shown in the plot. This turned |
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Wed Jun 19 18:45:14 2024, Luke, Update, , Vacuum chamber reassembly
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[Luke, Aiden, Mohak , Tyler]
On Tuesday we had the silver screws for the spherical cube shortened by a quarter of an inch so that they would fit into
the gate valve. We then attached the spherical cube to the vacuum chamber.
On Wednesday we finished assembling the RGA line and the main turbo pump.
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Mon Jun 17 11:47:46 2024, Liu, Infrastructure, General, Temporary cooling units for the labs
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Below are the temporary cooling units installed last week in labs 1119 and 1129. They are the temp. replacement for the building AC system, which will be
shut down during the Physics roof replacement. |
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Fri Jun 14 13:32:13 2024, Liu, Update, Scripts/Programs, COMSOL simulation on rectangular heater elements design 6x
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I have been looking at the feasibility of an alternative heater element design for FROSTI that replaces the original ring-like heater elements with n
rectangular elements with straight edges. They form an n-sided regular polygon that could well approximate the original annular ring if n is large enough.
This eliminates curved surfaces requirement for the heater elements, which was the source of the many month production delay for the prototype parts. |
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Mon Jun 3 14:14:39 2024, Tyler, Update, FLIR, Initial CIT FROSTI Analysis
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[Tyler]
Attached below are the initial results of the CIT FROSTI testing analysis.
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Mon Jun 10 14:52:38 2024, Tyler, Update, FLIR, CIT FROSTI Analysis Update
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[Tyler]
Upon further inspection, one adjustment was made to the FROSTI profile analysis: changing the transmission value of the ZnSe viewport. It
was initially assumed that the viewport possessed an AR coating, which would bring the transmission into the 90% range. Without the coating, it drops to
roughly 70%. Assuming no coating, the estimated delivered power was calculated to be 11.7 W. This is consistent with the estimated power given from the |
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Mon Jun 3 14:59:44 2024, Cynthia, Update, Interferometer Simulations, Created cavity scan with LG modes
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Mon Jun 3 09:24:48 2024, Aiden, Update, VAC, Vacuum Chamber Rendering
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Here is a new render of the vacuum chamber that includes the 2.75 tee to place the Argon leak right next to the RGA. The conical reducer under the spherical
cube was also replaced with a 4.5 blank. The height from the bottom of the blank to the bottom face of the chamber is 5.45". With the chamber now on 1"
standoffs, we will need a support with a height of 6.45". |
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Fri May 31 19:37:47 2024, Luke, Update, , Vacuum chamber Disassembly
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[Luke, Aiden, Jon, Michel, Tyler]
Work done:
On Tuesday (5/28) we removed the RGA line with minimal difficulty. On Wednesday (5/29) we removed the turbo
pump, which had a few bolts that we needed to cut. We borrowed a dremel with ceramic blades from the machine shop to help remove some of the bolts. On
Thursday we moved the vacuum chamber onto the floor to check and resecure the heating band on the bottom of the vacuum chamber. We then relocated the posts |
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Thu May 16 15:23:14 2024, Shane, Update, Cleanroom, Cleanroom cleaning and particle count
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[Luis, Michael, Luke, Shane]
cleaning cleanroom and particle count
1:45 pm: ran zero count test on particle counter
1:50 pm: started particle count
zone 3: 0.3 u: 2660 0.5
u: 3321.0 u: 41
zone 4: 0.3 u: 81060.5 u: 24941.0 u: 831
2:08 |
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Mon May 13 14:53:29 2024, Peter, Update, VLC Update, VLC
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| VLC Update WEEK 7 attached below |
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Mon May 13 14:48:27 2024, Aiden, Update, VAC, New Vacuum Chamber Design
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I created a new model for the vacuum chamber based on the ideas from last week's meeting.
It should be noted that we can not have the zero length
reducer and the gate valve on the same arm as they both have blind tapped holes. We need to decide if we want the gate valve or not as if we do, we will
need to use the 3 inch long reducer.
Important Measurements:
From the back of the flange to the back of the RGA: 25.25 in
Height from |
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Mon May 13 13:03:41 2024, Tyler, Update, FLIR, Readout Code Updates
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[Tyler]
Some changes have been made to the FLIR readout code to help improve its functionality:
More accurate temperature readings
than before due to updates in the calculation procedure. A bug was causing one of the parameters to not update correctly; this is now fixed.
Saved
data now stored in HDF5 files rather than CSV.
User can now enable automatic data storage by specifying a collection interval (in minutes). The |
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Tue May 7 20:34:31 2024, shane, Update, CDS, frosti MEDM screen update
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[Luis, Shane]
Here is the updated MEDM screen, with new orientation and updated labeling to reflect the actual positions of the heater elements. Note that
indices start at T0 to be consistent with simulink model, though in the previous elog for the FROSTI layout the heater elements are labeled 1-8.
Also,
we finally learned how to take a screenshot on debian. |
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Thu May 2 22:43:36 2024, Tyler, Update, Electronics, RTD Readout Chassis Redesign
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[Tyler, Jon]
Today the FROSTI RTD readout chassis underwent a redesign:
Instead of the original ratiometric method, which involved wiring the FROSTI RTDs in series, each element is individually powered by separate
excitations. Each element additionally possesses its own reference resistor of 100 Ohm. Now, if an RTD experiences an electrical short, it should not affect |
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Mon Apr 22 15:06:33 2024, Cynthia , Update, Interferometer Simulations, cavity scan update
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[Cynthia,Pooyan]
Completed some simulations injecting 0-10th order modes. Some graphs will be used for the poster after some further titles, axis, and
range adjustments. |
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Wed Apr 17 15:07:04 2024, Shane, Update, Cleanroom, Cleanroom cleaning and particle count
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[Mohak, Luke, Luis, Shane, Cynthia, Michael, Xuesi]
cleaning cleanroom and particle count
NOTE: particle counter was found dead, with the charging dock unplugged. For future reference, if you need to unplug
the dock, please either plug it back in when you're done, or make a note in an elog so someone else can come down and charge it. |
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Mon Apr 15 15:25:10 2024, Cynthia, Update, Interferometer Simulations, progress on simulation so far
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Mon Apr 15 11:51:03 2024, Peter, Update, VLC Update, VLC
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| An update on the VLC project is attached below: |
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Mon Apr 8 14:57:41 2024, Cynthia, Pooyan, Update, Interferometer Simulations, performed cavity scans for O4 O5, and coupled cavity
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Mon Apr 8 14:43:29 2024, Pooyan, Update, Interferometer Simulations, SIS update single and coupled cavities
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[Pooyan, Cynthia]
Attached is a brief recap PDF file. A video file showing separate HOMs plots for the cavity scan with ETM08 surface map is also
attached.
The codes are available at https://git.ligo.org/uc_riverside/hom-rh/-/tree/main/SIS |
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Sun Apr 7 13:42:51 2024, Michael, Update, Interferometer Simulations, Update on status of gtrace project
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[Pooyan, Michael]
After meeting and discussing the current state of our work with Prof. Fulda a few weeks ago, we have decided that the best next
step for the gtrace project is its integration into finesse work. Our first step towards this integration involved creating a sequential beam trace in
contrast to the previous non sequential gtrace simulations. A sequential beam trace not only allows for faster runtimes of the simulation ( |
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Wed Mar 27 00:03:57 2024, Pooyan, Update, Computers, Chimay relocation to Physics 1129
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[Jon, Pooyan]
Moved Chimay from the server rack in Physics 1119 to a new rack in Physics 1129. It is connected to the switch in that rack
and has the same ip address as before.
All services are up and running.
It appears that JupyterHub creates some processes whenever a user
connects to an instance of it, but in some cases does not stop those processes after the user is not using that instance. This results in having lots of |
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Sun Mar 24 11:50:37 2024, Aiden, Update, Clean & Bake, Cal Tech FROSTI Parts
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| Bagged the FROSTI legs and feet after the conclusion of the clean and bake. They are double bagged and sitting in the flow bench. |
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Sun Mar 24 11:49:27 2024, Aiden, Update, General, FROSTI RGA Scan
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Took RGA data 1 day after the conclusion of Bake 13. Bake 13 ended on Saturday March 23, the RGA data shown was taken on Sunday March 24. The scan shows
that the FROSTI is very clean with no outgassing. The HC levels are at 25 e-10. The pressure in the chamber was also a 1.64 e-8 Torr. |
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Tue Mar 19 15:22:27 2024, Aiden, Update, Clean & Bake, FROSTI Legs Clean and Bake
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[Aiden, Luke]
Cleaned and baked the Cal Tech FROSTI legs and showed Luke the procedure on how to clean parts. |
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Tue Mar 19 10:55:30 2024, Tyler, Update, FLIR, In-Air Optical Test
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Below is an image I took using the FLIR just before leaving for the LVK meeting. The profile is roughly what we would expect (annular). Any distortions
seen are likely from the screen not being completely parallel to the plane of the FroSTI (i.e. the screen slightly bends in various locations). Next step:
In-vacuum test at CIT. |
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Fri Mar 15 16:58:55 2024, Aiden, Update, VAC, Vacuum Chamber Frosti Testing
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[Luke, Luis, Aiden]
On Thursday, March 14 - Took preliminary RGA scans of the empty chamber to compare later on. Vented the chamber and placed the FROSTI
into the chamber. Plugged in the DB-25 connectors into the feed through port and checked the connection to make sure there were no shorts before closing
the chamber and starting the pumps again.
On Friday, March 15 - The pressure in the chamber has come down to 7 e-6 torr. It seems to be coming down |
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Wed Mar 6 09:57:52 2024, Tyler, Update, TCS, FROSTI Wiring
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Upon finishing the FROSTI assembly last week, we ran into some electrical issues. An electrical short was found between two of the d-sub pins (2 and
8). It appears that the pins were somehow coming into contact with the aluminum surrounding them. This was causing the power supply to trip. The issue
was seemingly fixed by adjusting the positioning of the cabling leading out of the reflector. When handling the device in the future, please make sure |