 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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Mon Nov 20 10:10:50 2023, Tyler, Configuration, Electronics, RTD Logic/Schematic Diagrams
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Below are a basic diagram of what the RTD measurement circuit logically looks like and an example schematic of the actual wiring. The schematic wiring
will be placed internally into a chassis, connected to the RTDs via DB25 cable.
Note: The DB25 Breakout Board connector is Female, not Male. |
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Tue Nov 21 14:47:24 2023, Tyler, Update, Lore, 1129 Workbench Assembly Update 1
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[Tyler, Shane, Mohak, Cynthia, Luke, Michael, Luis]
Started assembly of the workbench equipment today. We completed the stools, and have constructed the frames of each workbench. All that needs to
be added are the tabletops and the top shelves, which will be done on Monday. |
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Mon Nov 27 14:22:30 2023, Tyler, Update, Lore, 1129 Assembly Update
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[Tyler, Michael, Luke, Cynthia]
The tabletops have been attached to the workbench frames. Unfortunately, one of the tabletops came out of the box
with a large scratch and small dent in the middle. One of the electric top shelves is ready to be attached to the undamaged table, but the other is yet
to be opened. Assembly will be completed Wednesday morning.
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Thu Nov 30 13:50:32 2023, Tyler, Update, Lore, Workbench Assembly Completed
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[Tyler, Luke, Aiden]
The workbenches are now completely assembled and put into their final places. Additionally, the tool chest has been moved.
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 Tue Jan 9 12:08:59 2024, Tyler, Configuration, Electronics, RTD Readout Chassis Update
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Below is the current state of the RTD readout chassis wiring. Initial continuity tests seem good, will run through one more time to confirm.
Quote:
The custom front and rear panels for |
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Tue Jan 16 12:20:21 2024, Tyler, Configuration, Electronics, RTD Readout Chassis Update 2
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I performed another continuity test on the RTD chassis wiring, and everything seems to be set up correctly. The chassis should be ready for installation.
Quote:
Below is the current state of the |
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Tue Jan 23 12:17:41 2024, Tyler, Update, Electronics, RTD Chassis
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After updating the wiring in the RTD Chassis, a signal is now seen at each ADC input. However, there seems to be a discrepancy between the voltages
I measured out with the multimeter (see below). Next steps include:
Finish final debugging
Calibrate ADC inputs with known voltage source (likely to use DAC).
Voltage Readings:
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Tue Jan 30 11:36:19 2024, Tyler, Update, Electronics, RTD Chassis
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Quote:
After updating the wiring in the
RTD Chassis, a signal is now seen at each ADC input. However, there seems to be a discrepancy between the voltages I measured out with the multimeter (see |
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Tue Feb 13 11:54:45 2024, Tyler, Configuration, FLIR, In-Air Optical Test Configuration
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Below is the proposed schematic for FROSTI optical testing, chosen so enough space is allotted for prototype assembly.
Steps to be taken include:
Reconstruct FLIR staging apparatus
Move test mass stand-in to cleanroom
Mark FLIR camera position on cleanroom |
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Tue Feb 13 12:26:23 2024, Tyler, Update, Interferometer Simulations, BS Code Update
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I reproduced Cao's CE beamsplitter code (see below for example plots). I received the current info on the beamsplitter parameters for A+ and A# from
GariLynn also. The next steps are to perform a similar power loss analysis on the anticipated A# beamsplitter. |
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Tue Feb 20 11:31:49 2024, Tyler, Update, Cleanroom, Garment Cabinet Door Replacement
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[Luis, Luke, Pooyan, Tyler]
The replacement door for the HEPA garment cabinet arrived last week, and was installed on Thursday. However, it looks
like there's a small gap between the door and where the hinge is attached to the cabinet frame. No screws were provided with the replacement door. If we
want to perform any adjustments, we have to be very careful; the screws break very easily.
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Fri Feb 23 18:03:27 2024, Tyler, Update, FLIR, Optical Test Setup in Cleanroom
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[Tyler, Xuesi]
The FLIR and test mass stand-in have been transferred into the cleanroom. A software test will be run as soon as we get an ethernet
cable long enough to reach into the cleanroom where the camera is set up. Once this is finished, the FLIR will be moved aside for construction of the FROSTI!
When completed, the camera will be placed back into position for in-air optical testing.
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Wed Feb 28 12:02:08 2024, Tyler, Update, General, Resistors for Heater Elements Update
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Power Res (Ohm) RTD Res (Ohm)
Heater 1= 72.8; 80.6
Heater 2= 69.5; 80.8
Heater 3= 70; 83.2
Heater 4= 70.6; 78.7
Heater
5= 69.9; 80.6
Heater 6= 71.1; 78.2
Heater 7= 68.5; 76.8
Heater 8= 70.1; 82.8
Quote:
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Wed Feb 28 17:49:18 2024, Tyler, Update, TCS, FROSTI Assembly - Days 2-3
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[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.
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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 |
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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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Thu Mar 21 16:56:42 2024, Tyler, Update, DAQ, RTD Parameter Calibration
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[Jon,Tyler]
We noticed that the RTD temperature readings given on the Cymac were off, and traced the issue to miscalibration in the relationship
between the resistance and temperature of each RTD (Callendar-Van Dusen eqn). Below is the table of values inferred from independent measurements of temperature
and resistance to rectify this problem. This data was then fitted to better determine the coefficients present in the temperature-resistance relation: |
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Mon Mar 25 10:55:33 2024, Tyler, Update, DAQ, RTD Parameter Calibration
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Refitted RTD calibration, neglecting quadratic term:
R_0 (ohm) Alpha (1/C)
RTD 0 79.3962 0.002031
RTD 1 78.2874 0.002530 |
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Tue Mar 26 13:51:56 2024, Tyler, Update, DAQ, RTD Parameter Calibration
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Another re-fit, but this time the quadratic coefficient (beta) is set to 1.003e-6:
R_0 (ohm) Alpha
(1/C)
RTD 0 79.7386 0.001863 |
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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 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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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 Jul 29 13:39:16 2024, Tyler, Update, DAQ, RTD Parameter Calibration
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[Tyler]
Using the data taken during the FROSTI testing at Caltech, I attempted to find a better calibration of the RTD sensors, given our past issues
with inaccurate readings. The fit parameters, alpha and beta, are still all different from the initial values given to us by Fralock (alpha = .003, beta
= 1.003e-6, R_0 was not given), but the true values will differ based on factors such as part geometry.
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Mon Jul 29 14:30:16 2024, Tyler, Update, Cleanroom, RIN Measurement Set-up
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[Tyler]
I have begun moving parts into the cleanroom for the upcoming FROSTI RIN tests that will be conducted within the next few weeks. While waiting
for the rest of the equipment to arrive to perform the full-scale tests, I have additionally moved the FROSTI under the shelf above the optical table,
where it will stay for the meantime. As always, please use caution when in the cleanroom. Aside from the FROSTI, the IR photodetectors that will be used |
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Mon Aug 12 16:24:34 2024, Tyler, Update, Cleanroom, RIN Measurement Update 1
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[Tyler]
For some preliminary tests, I moved the IR photodetectors outside of the cleanroom and onto the other optical table. The basic goal was
to obtain a signal from both photodetectors. To achieve this, one of the heater cartridges used for early FLIR measurements months ago was hooked up to
a power supply (PS). The PS was set to supply 0.20 A with a voltage of 2.8 V; the corresponding power is thus 0.56 W. With this, I was able to measure |
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Tue Sep 3 18:24:17 2024, Tyler, Update, CDS, Cymac Timing Chassis Issue
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[Tyler, Jon]
The timing chassis used for the cymac has been shut off due to an unknown issue causing its supplied current to fluctuate. All real-time
models will be suspended until a solution is found.
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Mon Sep 16 14:59:51 2024, Tyler, Update, TCS, FLIR RIN Update 09/16
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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. |
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Mon Sep 23 15:11:21 2024, Tyler, Update, Scripts/Programs, Effective Emissivity Analysis and RIN Update
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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 |
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Wed Oct 2 12:20:43 2024, Tyler, Update, TCS, Updated FROSTI Analysis 10/02/2024
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| Attached below are updates on current FROSTI prototype analysis. |
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Wed Oct 9 13:52:31 2024, Tyler, Update, TCS, RIN Update 10/09/2024
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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. |
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Tue Oct 29 16:37:35 2024, Tyler, Update, Electronics, Red Pitaya OS Update
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The Red Pitaya ecosystem has been upgraded to OS 2.00-35, with a key feature being greater freedom in adjusting the sampling frequency for signal
analysis. Before, decimation factors could only be applied if they were a power of 2 (i.e 2,4,8,16,...) up to 65536. Now, the factors can be any power
of two up to 16, and any whole number greater than 16 up to 65536. Further information can be found here. |
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Wed Nov 13 14:03:32 2024, Tyler, Update, Electronics, RIN Update
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[Tyler]
We've added two low-pass filters in hopes of reducing any potential aliasing that may be introducing additional noise into the power spectra
for the RIN measurements. It still looks like the noise levels are too high. Attached below are some recent measurements taken with the FROSTI powered
on and off.
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Wed Nov 20 12:59:37 2024, Tyler, Update, Electronics, RIN Update
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I went ahead and compared the noise spectrum of the ADC to those of the photodetectors with the FROSTI on and off. As discussed last meeting, it looks like
the measurements with the Red Pitaya (RP) are limited by the ADC noise floor. Another avenue to explore in this measurement could be switching to the
cymac ADCs. |
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Wed Nov 27 13:48:01 2024, Tyler, Update, Electronics, RIN Update
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[Tyler]
I downgraded the Red Pitaya back to OS 2.00-18 due to runtime errors during measurement. Once I did this, the device appeared to work much
better than it has the last few weeks. First, it appears we can actually see the cutoff of the added low-pass filters that were added in to the RIN setup.
Second, there does appear to be a difference again between the FROSTI ON state versus the dark state (i.e. FROSTI OFF). A long measurement of the ADC noise |
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Wed Dec 11 13:39:30 2024, Tyler, Update, Electronics, RIN Update 12/11/2024
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[Tyler]
Attached below are updated ASD plots for the FROSTI RIN measurements. The parameters set for this are the following:
DFT Size (N): 16384
Sampling Frequency (F_s): 7.629 kHz
Resolution (F_s/N): 0.93
CH0 DC Voltage w/FROSTI
ON: 113.6 mV
CH0 DC Voltage w/FROSTI OFF: -5.7 mV
CH1 DC Voltage w/FROSTI ON: 113.0 mV
CH1 DC Voltage w/FROSTI OFF: |
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Wed Dec 18 15:41:56 2024, Tyler, Update, TCS, FROSTI RIN
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[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. |
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Mon Dec 23 14:33:36 2024, Tyler, Update, TCS, Latest RIN Measurement Results
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| Attached below are the measurements I took from the FROSTI from 12/18-12/22. |
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Tue Jan 14 10:27:14 2025, Tyler, Update, TCS, RIN Updates
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[Tyler]
Attached below are updated plots for the FROSTI RIN measurements for Jan 14 group meeting.
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Fri Jan 17 13:27:07 2025, Tyler, Update, TCS, FROSTI Pre-disassembly
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[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.
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Wed Jan 22 10:50:08 2025, Tyler, Update, TCS, FROSTI Disassembly
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[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 |
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Tue Feb 18 10:12:39 2025, Tyler, Update, TCS, Final RIN Plot Update
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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: |
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Tue Mar 4 10:28:58 2025, Tyler, Update, TCS, RIN Plot Updates
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Tue Mar 25 12:56:47 2025, Tyler, Update, TCS, FROSTI Analysis Finalization
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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. |
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Tue May 6 12:25:03 2025, Tyler, Configuration, CDS, Cymac ADC CSD measurement
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An initial measurement of the cymbal ADC CSD is attached below. As of now, it seems that the sensitivity limit is roughly the same as that of the Red Pitaya.
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Tue May 13 12:41:06 2025, Tyler, Update, TCS, A# Profiles Update
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| Slides on the A# ITM FROSTI profile modeling efforts can be found here. |
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Tue Jun 17 12:46:47 2025, Tyler, Update, Electronics, CyMAC ADC Noise
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Below are results from power spectra measurements of the CyMAC ADC, computed form 30 hours of time series data, compared to the performance of the Red Pitaya.
The frequency resolution for the initial Cymac CSD is 2 Hz, and 216,000 spectra measurements are averaged together. As of now, it still looks like we haven't
reached the correlated noise floor of the CyMAC. We have a few days worth of data to take from, so I'll look into using a longer period of time. |
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Tue Jun 24 12:45:16 2025, Tyler, Update, General, Updated ADC spectra
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[Tyler]
Updated ADC noise spectra measurements using diaggui.
NOTE: Will update plots with proper axes |
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Tue Jul 1 12:39:42 2025, Tyler, Update, TCS, A# FROSTI Profile Optimization Update
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[Tyler, Liu]
Slides |