ligo-ex ligo-ds
  Richardson Lab Experimental Log, Page 4 of 11  Not logged in ELOG logo
New entries since:Wed Dec 31 16:00:00 1969
ID Date Author Type Categorydown Subject
  491   Tue Dec 17 13:53:53 2024 LuisUpdateVACVacuum system status

[Luis]

The vacuum system is being baked. I disconnected the digital gages and the magnets, opened the Ar leak and started the bake by taking the temperature from 60C-90C-125C waiting about 15-20 minutes between each interval. The RGA electronics were left on since the temperature of the flange was 36.6C (bellow the 60C threshold)

  493   Thu Dec 19 12:00:44 2024 LukeUpdateVACEnd of bake

The vacuum chamber has stopped baking. 

Current state as of 11:40, 12/19/2024:

The gate valve is open, and the filament of the RGA is on.

The temperatures were steady at:

PID right: barrel upper: 129°C,  RGA volume: 125°C

PID left: barrel lower: 125°C, Lid: 114°C

The RGA flange was 37°C

Cleanroom was 26°C

Note the upper barrel was very close to the emergency shut off temp of 130°C. In the future we may want to either rewire some of the heating tape or lower the set temperature of the right PID controller.

Luis and I are planning on taking an RGA scan of the MR on Sunday before the campus shuts down for the holidays.

  494   Sun Dec 22 20:43:35 2024 LuisUpdateVACMR Testing

[Luis, Luke]

RGA Volume: T = 23°C, P = 3.0e-9 Torr
Main Volume: T = 22°C, P = 9.90e-9 Torr

After letting the vacuum cool down for a couple days, we reattached the magnets and sensors, then we performed a RGA scan of the vacuum system, now containing the MR sample. The results are attached below. Something to notice is that we are technically not under UHV, though Luke and I believe the reading of the sensor is not completely accurate since it was still coming to a steady state, further test will be performed when the physics building is open again.

  496   Thu Jan 2 17:52:58 2025 LuisUpdateVACMR Testing Continuation

[Luis, Luke]

RGA Volume: T = 22°C, P = 2.10e-9 Torr
Main Volume: T = 21°C, P = 5.71e-9 Torr

Measurements of the current state of the vacuum systems were taken today, now that the system had reached UHV status, the results are attached bellow. The first plot overlays the data of the empty chamber taken on 12/16/24 before inserting the MR material, and the data of the system today, with the MR inside. The second plot displays the S/N Ratio of the system. The last plot displays the data of the system with the Ar leak open and closed. Notice that it is common for the Ar leak close data to fail due to the calculation of the gas flux per unit ion current, which is dependent on the Ar peak.

  509   Fri Feb 7 12:25:56 2025 Luke SummaryVACStarted bake

[Luke, Luis]

The vacuum chamber is currently baking. 

We stepped up to 120°C by increments of 30°C starting at 60°C. We took about an hour break at 90°C to let the temperatures equilibrate.  

Current state as of 12:20:

The gate valve is open, the calibrated Argon leak is open, and the filament of the RGA is on.

The temperatures are as follows:

PID right barrel upper: 113°C,  RGA volume: 120°C

PID left barrel lower: 121°C, Lid: 114°C

The lower temperatures should climb as the whole system heats up. 

 

  510   Tue Feb 11 08:07:02 2025 LuisUpdateVACBake stopped

[Luis, Ma]

Feb/10/25 4:00pm

Bake was stopped.

  511   Fri Feb 14 11:57:50 2025 LuisUpdateVACVacuum Update

[Luis]

Feb/11/25 9:30am

Pressure gages were connected.

  512   Fri Feb 14 12:15:23 2025 LuisUpdateVACVacuum sytem staus

[Luis, Luke, Ma]

February 12, 2025 - 4:00 PM

We performed an RGA scan with the vacuum system containing the heater elements. The results are attached below.

Pressure (Torr) Temperature (°C)
RGA Volume 3.13 × 10⁻⁹ 23
Main Volume 6.15 × 10⁻⁹ 23

As we can see, we are not yet under cleanliness standards. The passing threshold is 4 × 10⁻¹⁰, and we are currently measuring nearly double this value. We will continue performing scans to monitor any changes in these readings.

  517   Tue Feb 18 11:19:13 2025 Luke ConfigurationVACRepositioning of the lid's temperature probe
Before the recent bake I slightly repositioned the temperature probe on the lid from beside the heater tape to under the heater tape. This was done to better know and control the temperatures of the chamber while baking. It has appeared to work with the temperatures being held very close to the 120C target.
  519   Thu Feb 20 17:07:36 2025 LuisUpdateVACRGA Scan

[Ma, Luis]

February 20, 2025 - 3:30 PM

Ma performed an RGA scan with the vacuum system containing the heater elements. The results are attached below.

Pressure (Torr) Temperature (°C)
RGA Volume 1.87× 10⁻⁹ 23
Main Volume 5.70 × 10⁻⁹ 23

As we can see, we are not yet under cleanliness standards. The passing threshold is 4 × 10⁻¹⁰, we are very close to it.

  522   Mon Feb 24 17:50:13 2025 LuisUpdateVACRGA Scan

[Ma, Luis]

February 24, 2025 - 1:00PM

Ma performed an RGA scan with the vacuum system containing the heater elements. The results are attached below.

Pressure (Torr) Temperature (°C)
RGA Volume 3.31 × 10⁻⁹ 25
Main Volume 5.75 × 10⁻⁹ 24
  11   Mon Oct 3 17:21:39 2022 CaoUpdateTCSInspection of macor parts
The macor parts arrived and inspected today. These include:
  1. Macor spacer (drawing: LIGO_Redesign_Macor_Spacer_Drawing_v4.pdf attached below), quantities: 40
    • No defects, damages observed
    • Parts are free from grease/ machining fluid
    • Wall thickness of 1 mm appear to provide sufficient stiffness to part
    • Images of parts: Macor_spacer_0.jpg, Macor_spacer_1.jpg
  2. Macor 5-40 UNC screw (drawing: LIGO_Redesign_Macor_Screw_Drawing_v6.pdf attached below), quantities: 20
    • One screw broke, location of break: should edge between head and shaft (see image Macor_screw_5.jpg )
    • All other screws look ok, no damage observed, clean surface overall
    • Images: Macor_screw_0.jpg , Macor_screw_4.jpg
  173   Thu Jul 27 10:18:43 2023 CelesteUpdateTCSGraphical Updates to HOM RH Modification
Attached are updated graphs of the irradiance distribution from the 1/8th ring heater units (extruded and reduced in length).
  180   Fri Jul 28 17:45:45 2023 CelesteUpdateTCSGraphical Updates to HOM RH Modification, Friday 7/28
Updated 1/8th Heater simulation modification graphs. Slides 7, 10, 16-19 are new additions.
  187   Tue Aug 1 16:22:35 2023 CelesteUpdateTCSGraphical Updates to HOM RH Modification, Tuesday 8/1
Slides 20-33 are newly added (data/graphs from parameter sweep feature-1/8th heater unit length varied from 10% of original to 100% of original).
  200   Thu Aug 10 14:13:38 2023 CelesteUpdateTCS8/10/23, Simulation Graphical Progress
  204   Fri Aug 11 10:57:20 2023 CelesteUpdateTCS8/11/23 Simulation Progress
  209   Tue Aug 15 16:10:06 2023 CelesteUpdateTCS8/15/2023 Simulation Progress
  291   Mon Dec 11 16:20:17 2023 JonSummaryTCSFROSTI Assembly Procedure

Below is the procedure we will follow to assemble the FROSTI prototype.

  1. Install SS guide rods and bottom Macor spacers in bottom reflector
  2. Install AlN elements on top of bottom Macor spacers
  3. Install upper Macor spacers on top of AlN elements
  4. Feed unterminated power and RTD leads through slots in upper reflector
  5. Install upper reflector, using guide rods to slowly lower into position
  6. Install vented SS bolts for reflectors; Macor bolts for heater elements
  7. Remove SS guide rods
  8. Bundle power and sensing cable with PEEK cable ties and SS cable mounts
  9. Terminate power and sensing cable bundles with PEEK DB25M connectors
  341   Mon Feb 26 21:23:27 2024 JonUpdateTCSFROSTI Assembly - Day 1
[Jon, Tyler, Luis, Luke, Mohak, Cynthia, Michael, Aiden]

FROSTI assembly began today. After a final set of RGA scans were taken, the vacuum chamber was vented and the reflectors were removed. The chamber was then resealed and pumped down again. 

Today we completed the installation of the Macor hardware and heater elements between the two reflector halves. Tomorrow we will route, bundle, and terminate the power and sensor cables. 

  345   Wed Feb 28 17:49:18 2024 TylerUpdateTCSFROSTI Assembly - Days 2-3
[Aiden, Jon, Luis, Luke, Michael, Tyler]

FROSTI assembly was completed today. The RTD and power wires were terminated at the DB-25 connectors and the legs were put on. It is currently placed in front of the stand-in test mass (~5 cm away). The FLIR has also been moved back to it's nominal position. As of now, it appears there are some shorts within the power cabling. This will be a focus of tomorrow's work.

Quote:
[Jon, Tyler, Luis, Luke, Mohak, Cynthia, Michael, Aiden]

FROSTI assembly began today. After a final set of RGA scans were taken, the vacuum chamber was vented and the reflectors were removed. The chamber was then resealed and pumped down again. 

Today we completed the installation of the Macor hardware and heater elements between the two reflector halves. Tomorrow we will route, bundle, and terminate the power and sensor cables. 

 

  347   Wed Mar 6 09:57:52 2024 TylerUpdateTCSFROSTI Wiring

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 to keep the wiring as undisturbed as possible. The setup is rather fragile, and moving the cabling around could potentially reintroduce a short like this.

  442   Mon Sep 16 14:59:51 2024 TylerUpdateTCSFLIR RIN Update 09/16

Below is the dark noise spectrum of the Red Pitaya, which was measured over the course of a weekend. Additionally, I have successfully measured a signal from the photodetectors with the FROSTI as the IR source, so it seems there shouldn't be any worry of these particular detectors not being feasible for the RIN measurement.

  453   Wed Oct 2 12:20:43 2024 TylerUpdateTCSUpdated FROSTI Analysis 10/02/2024
Attached below are updates on current FROSTI prototype analysis.
  457   Wed Oct 9 13:52:31 2024 TylerUpdateTCSRIN Update 10/09/2024

I tried adjusting the gain settings on the photodetectors to check if this would help improve the RIN spectra measurements. Overall, it doesn't look like it does, and if anything, looks worse. I assume this is so because as the gain is lowered, the amount of detectable signal from the FROSTI becomes smaller and smaller.

  492   Wed Dec 18 15:41:56 2024 TylerUpdateTCSFROSTI RIN
[Tyler]

I have begun the (hopefully) final RIN measurements at 3:30 PM today. If you need to go into the cleanroom at any time between now and Sunday (the 22nd), please do not touch the FROSTI, the Red Pitaya, the photodetectors, or any of the wiring.

  495   Mon Dec 23 14:33:36 2024 TylerUpdateTCSLatest RIN Measurement Results
Attached below are the measurements I took from the FROSTI from 12/18-12/22.
  498   Tue Jan 14 10:27:14 2025 TylerUpdateTCSRIN Updates
[Tyler]

Attached below are updated plots for the FROSTI RIN measurements for Jan 14 group meeting.

  499   Fri Jan 17 13:27:07 2025 TylerUpdateTCSFROSTI Pre-disassembly
[Tyler, Ma, Cece, Jon, Luke, Cynthia, Michael]

On Tuesday, we prepared the FROSTI for disassembly in anticipation of the APS filming that is set to take place in the labs. The FROSTI has been unbolted from the optical table in the cleanroom, with its wires weighted down and the majority of its screws removed to ensure an easy removal of the reflectors during the filming process.

  501   Wed Jan 22 10:50:08 2025 TylerUpdateTCSFROSTI Disassembly
[Tyler, Ma, Cece, Luis, Shane, Luke, Cynthia, Liu, Jon]

On Tuesday (Jan 21), we took the FROSTI apart in front of a filming crew. It was a success! The footage is going to be used in an APS video detailing the experimental cosmology research conducted in the department.

The FROSTI reflectors, heater elements, and legs were all bagged separately and a currently being stored in the cleanroom. If you need to do any work in there, please be mindful of these parts. The elements are currently on the shelf above the optical table, and the reflectors are placed on the table in the back corner.

  516   Tue Feb 18 10:12:39 2025 TylerUpdateTCSFinal RIN Plot Update

Below is a preview of the final RIN figure that will be included in the FROSTI instrument paper. A quick summary of what is shown below:

The original RIN CSD measurement is shown on the top panel in red. Frequency bins that exhibit external electronics noise (ex. ADC, photodetector noise, etc.) are identified and shaded in gray. These noisy bins are then excluded from the dataset before beginning the next step in the analysis process: rebinning. Here, the resolution of the spectrum can be changed by averaging frequency bins together within a specified interval, with the goal of pushing the measurement curve closer to the A+ requirement shown in the figure. For demonstration below, the spectrum goes from a resolution of ~0.93 Hz to 14.90 Hz.

  531   Tue Mar 4 10:28:58 2025 TylerUpdateTCSRIN Plot Updates
  542   Tue Mar 25 12:56:47 2025 TylerUpdateTCSFROSTI Analysis Finalization

Upon final review of the FROSTI analysis included in the (hopefully) soon-to-be submitted instrument paper, I've made some adjustments to the reflectivity analysis that estimates the amount of power delivered to the test mass by the FROSTI. Initially, as detailed in elog 447, the delivered power was approximated to be 12.6 W (later adjusted to 12.9 W), with roughly 18% of this power being reflected by the test mass. After some final adjustments, this value now is closer to 12.0 W, with 10.2 W absorbed (15% power reflection). Below is a table showing the updated values for the FROSTI prototype tests:

Old Value New Value
Delivered Power 12.9 W 12.0 W
Absorbed Power 10.6 W (18% reflectivity) 10.2 W (15% reflectivity)
Measured Peak Temperature Difference 5.39 +/- 0.03 K 5.26 +/- 0.03 K
Model Peak Temperature Difference 5.42 K 5.21 K
Measured Peak OPD 765 +/- 9 nm 771 +/- 7 nm
Model Peak OPD 630 nm 654 nm
  162   Tue Jul 18 14:13:46 2023 Sophia UpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis
We [Sophia and Tyler] have found a code which will partition our data and generate PSD's and CSD's automatically. We are now in the stage of writing this into a dynamic code, which so far has been fast-paced because of the framework we have built for it over the past few weeks. Something to note is that we have found, especially over long periods of time, the laser goes through periods of extreme noise and the signals often cross from where we set them at some point throughout our data collection. We have made the assumption that this is something to do with the laser itself, and not our setup or surrounding space because of both the times that these noise/intensity spikes took place and the duration of the spikes (1.5-2.5 hours). To try and correct for this, we have been "cutting" the noise, and just looking at sections which don't include these big fluctuations. An example of the "noise cut data" is shown in the graph titled "Signals Over Time 7-18-23 Noise Cut Data" and all of the PSD/CSD graphs have been made using only these "noise cut" regions.
  174   Thu Jul 27 11:28:36 2023 Sophia UpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis: Dynamic CSD and PSD Plots
This week I have successfully been able to implement our dynamic CSD and PSD plotting code, but along the way I encountered a few challenges which I will outline in this elog post. Challenges: 1. Once I was able to plot the data through time, I produced a graph of the raw data (shown below in the top to images) which showed pulsed data instead of a continuous stream. On Tuesday (26th of July) Tyler and I fixed this issue, realizing that calling the starting the trigger in the red pitaya was the issue. When I commented that line of code out, it immediately started plotting continuously. 2. When that issue was solved, We then started having problems with the automatically generated lines in the python program which would double back on each new iteration. I am still dealing with this issue, because the line likes to follow the progression of the data intake instead of through the plot. Currently, I am trying to plot the data as a scatter plot and then add the line as this might make it care only about the data's distribution instead of the order of the points in the list, but I am still unsure. I might try out np.sort (or some equivalent to sort the entire data set before plotting) as well.
  175   Thu Jul 27 14:11:42 2023 SophiaUpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis: Dynamic CSD and PSD Plots
Here's a screen recording of the dynamic raw data and PSD/CSD plots as they are now. Will begin working on implementing a code to generate the statistical estimator for the CSD uncertainty now. (Will talk to Tyler more about whether I can get the lines to happen or not)
  183   Mon Jul 31 19:27:30 2023 SophiaUpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis: Dynamic CSD and PSD Plots
An update on the CSD/PSD code: The code is now taking a dynamic average of the points, and that has significantly reduced the noise that we were reading and the issues I was having with the lines in the plots. The graph for the CSD is still putting up a fight though, and amassing many lines that do not appear when just scatter plotted. I plan to fix that tomorrow, alongside inserting my own generated signal into the data. I have plotted the coherence alongside these graphs (as shown in the first screen recording and in one of the images), and it is significantly less than 1-- starting at or below 10^(-1). As a note, I am unsure of why the raw data looks like this-- the laser goes through periods of extreme noise and I think this data was taken during one of them.
  186   Tue Aug 1 15:44:31 2023 SophiaUpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis: Dynamic CSD and PSD Plots
We have identified two problems facing the intensity noise calculations, which we are working to solve. The first of these problems, is that the red pitaya appears to be taking data approximately 4 times faster than we would expect from the decimation rate based on how quickly it runs. To see if this was affecting our data, we plugged the red pitaya into a function generator. We found that my code is able to identify the driving frequency, but consistently gives predictions that are roughly 7% greater than we expect. When we drive at 100 Hz, the plot says the peak is at 107 Hz, when driven at 400 Hz, we see between 422-427 Hz, etc. While this implies that the red pitaya is not taking data at a faster rate than we would expect (if it did we would anticipate a lower than expected frequency, by a factor of roughly 4), it does imply some intrinsic issue with either the red pitaya or with the code. To fix this, I am going to use my code on artificially generated signals and see if we still observe these issues.
  194   Mon Aug 7 15:36:18 2023 SophiaUpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis: Dynamic CSD and PSD Plots
Today I was able to fix the red pitaya's plotting problem, and get my code to recognize driving frequencies from the function generator to within a 0.5 Hz estimation. The sinusoidal plots I have included are from sending a 1 Hz signal into the red pitaya to see the signal in real time. This allowed me to see exactly where the system was messing up, and fix from the ground up. Once I had that working, I began to test sending in frequencies in the range that my PSD/CSD code could observe and I was able to identify each driving frequency within 0.5 Hz. My code was able to correctly identify a 500 Hz signal, while other analyzed frequencies in the observable range have fallen lower than the sent in frequency by a less than 0.5 Hz. I believe this issue comes from the strange speed that the red pitaya is still acquiring data, even with my fixing it to now observe a continuous signal.
  196   Tue Aug 8 16:47:11 2023 SophiaUpdateScripts/ProgramsUpdate on Dynamic CSD and PSD Plots
We have fixed our rapid plotting error, and realized that this has not been affecting our data intake! Below is a video of the code progressing, alongside grabbed images of the raw data. The data is now continuous, and performs as we expect. Next, I plan to add a widget which will dynamically show the peak values instead of them just being printed in the terminal after each iteration. (Ignore the red box-- it was from me struggling with a now fixed issue).
  206   Tue Aug 15 10:35:00 2023 SophiaUpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis: Dynamic CSD and PSD Plots
I have successfully added a button to my graphics, but it has posed a strange issue with the CSD and PSD values. When I plot my original code, I still see the pretty peaks that I was getting originally, while my new code (as shown in the video and in the last screenshot) is giving me more of a line. In my code that gives the peak values, the CSD values also tend to fluctuate in this new code as well (shown in the first screenshot), before returning to the real value. I think that there is a problem with the averaging and am hoping to solve this issue today with Tyler. This is good progress though!
  207   Tue Aug 15 13:32:37 2023 SophiaUpdateScripts/ProgramsUpdate on Laser Noise Data Collection and Analysis: Dynamic CSD and PSD Plots
I have now fixed all issues that I was having this morning, and have added text boxes which show the peak values of both PSD's and the CSD alongside the graphs. They also update continuously with the graph. This is shown in the top image. The laser was driven at 400Hz, and had 0.5V peak to peak voltage, both of which appear correctly in the below graphs. Now that the code is almost fully working (we will finish debugging the screenshot method later today), our plan tomorrow is to drive the laser and see how the code performs with it. The below graph is from us driving the function generator at 100Hz to test the range. Update: Bottom graph is new version of graphs with better distribution of both graphs.
  249   Mon Oct 30 11:03:56 2023 TylerUpdateScripts/Programs 

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.

  317   Tue Feb 6 22:40:25 2024 MichaelUpdateScripts/ProgramsLong Crab 1 Design Created In Gtrace
Worked on and completed the python code for the simulation of the Long Crab 1 layout for Cosmic Explorer basing off of Pooyan's original work with the Crab 1 layout. From here I'll look into creating the shoelaces layouts.
  376   Fri Jun 14 13:32:13 2024 LiuUpdateScripts/ProgramsCOMSOL simulation on rectangular heater elements design

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.

This design was implemented in COMSOL, shown in the attached. From the face on view, each element has a trapezoid shape with straight edges. The edges between neighboring elements are parallel, with a space of 2 mm in between them.

The ray tracing and thermal analysis obtained from COMSOL are shown in the attached pdf.

In particular, the 2D irradiance profiles were obtained from the ray tracing (so far from the front heating surfaces only). The 1D radial profiles were integrated and shown in the attached. The power delivery efficiency for the original ring-like heater element design is integrated to be roughly 65%, for comparison. The plot also shows the radial irradiance profiles for three different straight-edge designs, which correspond to 16 edges, 18 edges, and 24 edges. We see that with the straight-edge designs, the irradiance profiles stay in a good Gaussian shape. In addition, with a larger number of edges, the power efficiency increases, but is always less than the case for the optimized ring-like design.

The thermal distortions for the TM were also obtained from COMSOL, using the irradiance profiles at the TM HR. As shown in the attached, with the straight-edge design, the effects on the thermal lens OPD and the HR surface deformation are similar to the ring design, but with less severe edge roll-off for instance.

  380   Fri Jun 21 11:47:30 2024 LiuUpdateScripts/ProgramsCOMSOL simulation on alternative straightened heater elements design

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 out to result in similar but less prominent thermal effects.

They only differ from the original baseline design by a source power rescaling, however, as shown in the plot, where we see the power-rescaled irradiance profiles for the straight edge designs are close to that for the ring design. The resulting temperature profiles and thermal distortions are shown in plot and plot. The thermal effects for the 16 straight-edge design with renormalized source power for instance are strikingly similar to that for the original ring design.

An alternative straightened heater element design has also been investigated with COMSOL FEA simulation. As shown in the attached, in this new design each heater element component is cut with multiple straight edges but remains connected, shown in the same colors (green and red). In the example, four straight edges are cut from each of the four heater components (4x4=16 edges in total). There is no spacing between the neighboring edges from the same element component, but the edges from different components are separated by 2mm, as can be seen in the attached. This new N-in-one straight edge design offers similar irradiance compared to that for the evenly-spaced N-sided regular polygon straight edge design with the same number of edges, as shown in the plot. It however has fewer heater components, four in this case, which makes it easier to implement in assembly and wiring, and less vulnerable to electrical and thermal shorts with their fewer heater element pins.

  387   Thu Jun 27 11:09:14 2024 LiuUpdateScripts/ProgramsStraight edge STEP files and ray loss analysis

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 figure. The amount of light rays deposited back to the heater is small when close to the center, where it is closer to the original ring. The ray power increases as we move further away from the center toward the edges. In addition, the total power integrated at the heater's front surfaces is about 21% of the original heater's emitted power. This could account for the power efficiency difference between the straight edge design and the ring design, as shown in plot for instance.

  447   Mon Sep 23 15:11:21 2024 TylerUpdateScripts/ProgramsEffective Emissivity Analysis and RIN Update

A quick update on the effective emissivity analysis for the CIT FROSTI testing:

I was able to (roughly) match the OPD data to a referenced COMSOL model, with an applied power of 12.6 W (as seen below). However, when changing the emissivity of the ETM in COMSOL, the dT profiles do not seem to change much. I am not sure as to why this is the case at the moment, and will continue to look further.

Additionally attached are the current RIN measurements of the FROSTI prototype. Shown is the PSDs of both channels, in reference to their individual backgrounds.

  521   Sun Feb 23 16:00:07 2025 Luke UpdateScripts/ProgramsRingheater modeling Update

These are some plots:

The first shows the convergence of the 02 mode reducing the size of the mesh. The second shows the the numerical error of the zernike.

The first is found by sweeping a parameter that changes the size of the mesh. The HR surface was set to half a cm for all values.

The second by taking the inner product of a zernike mode with its self and calculating its deviation from pi for varying fineness of the mesh.

  541   Sun Mar 23 15:39:06 2025 Luke JohnsonUpdateScripts/ProgramsRingheater Location optimization
Attached are some plots that show a new parameter sweep with a finer mesh then before. I have also been able to get a heatmap of power of HOMs in a very simple finesse model.
ELOG V3.1.3-7933898