 Wed Jun 30 00:00:13 2010, Kathryn and Won, Computing, Hartmann sensor, rms of centroid position changes 
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Given below is a brief overview of calculating rms of spot position changes to test the accuracy/precision of
the centroiding code. Centroids are obtained by summing over the array of size 30 by 30 around peak pixels, as opposed to the old method of using matlab
built-in functions only. Still peak pixel positions were obtained by using builtin matlab function. Plese see the code detect_peaks_bygrid.m for bit more |
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Thu Jul 1 09:40:13 2010, James Kunert, Misc, Hartmann sensor, SURF Log 8 -- more SLED characterization 8x
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As I started setting up my next experiment, I noticed that the beam size from the SLED appeared to be larger than expected from previous analysis. It
was therefore necessary to conduct further experiments to characterize the divergence angle of the beam.
First, I set up the photodetector attached to an SLED and mounted a razor blade on a translational stage, in the same manner as done previously. |
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Sun Jul 4 06:45:50 2010, Kathryn and Won, Computing, Hartmann sensor, analyzing the wavefront aberration
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Happy Fourth of July!
The following is a brief overview of how we are analyzing the wavefront aberration and includes the aberration
parameters calculated for 9 different temperature differences. So far we are still seeing the cylindrical power even after removing the tape/glue on the |
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Tue Jul 6 21:57:19 2010, James Kunert, Misc, Hartmann sensor, SURF Log -- SLED fiber output temporal analysis 6x
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In the previous log, I describe the direct measurement of the fiber output beam using the Hartmann sensor with the plate removed. In order to analyze
how these properties might change as a function of time, we left the camera running over the holiday weekend, Dr. Brooks having written a bash script which
took images from the sensor every 500 seconds. This morning I wrote a MATLAB script to automatically analyze all of these images and plot the fit parameters |
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Thu Jul 15 20:06:37 2010, James K, Misc, Hartmann sensor, SURF Log: Thermally Induced Defocus Experiments
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A quick write-up on recent work can be found at: Google
Docs
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Tue Jul 20 15:45:51 2010, Aidan, Computing, General, Add fixed IP addresses to local machines in TCS lab
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| http://nodus.ligo.caltech.edu:8080/AdhikariLab/859 |
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Tue Jul 20 18:13:06 2010, Aidan, Computing, General, Added TCS channels to frame builder
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http://nodus.ligo.caltech.edu:8080/AdhikariLab/860
contents of tcs_daq: /target/TCS_westbridge.db
grecord(ai,"C4:TCS-ATHENA_ADC0")
{
field(DTYP,"ATHENA")
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Thu Jul 22 11:02:59 2010, Aidan, Computing, General, Restarted hartmann machine
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hartmann had started responding to requests to log-in with the a request to change the password. Attempts to change the password proved
unsuccessful. I tried to access the machine locally to change the password but I couldn't the display started, so I had to reboot it.
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Thu Jul 22 21:46:55 2010, James Kunert, Misc, Hartmann sensor, Hartmann Sensor Thermal Defocus Measurement Noise & Ambient Light Effects
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As discussed during the teleconference, a series of experiments have been conducted which attempt to measure the thermally induced defocus in the Hartmann
sensor measurement. However, there was a limiting source of noise which caused a very large displacement of the centroids between images, making the images
much too noisy to properly analyze. |
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Fri Jul 23 12:33:51 2010, Aidan, Computing, Hartmann sensor, Invar clamp scatter
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I illuminated the Hartmann sensor with the output of a fiber placed ~1m away.
I noticed that the illumination was not uniform, rather there was some sort of 'burst' or 'star' right near the center of the image. This turned
out to be due to the Hartmann plate clamps - it disappeared when I removed those. It appears that there is scatter off the inner surface of the holes through |
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Fri Jul 23 12:38:58 2010, Aidan, Computing, Hartmann sensor, Images for Dalsa
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Attached are the background and 80% illumination (~uniform spatially uniform) images that Dalsa requested.
Note that the gain of the taps does not appear to be balanced.
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Fri Jul 23 10:33:08 2010, Aidan, Computing, Hartmann sensor, Dalsa camera ADC 8th digitizer error
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I plotted a histogram of the total intensity of the Hartmann sensor when illuminated and found that the 128 count problem extends all the way up through
the distribution. This isn't unreasonable since that digitizer is going to be called on mutliple times.
First things first, the value of 128 equals a 1 in the 8th digitizer, so for a 16-bit number in binary, it looks like this: 0000 0000 1000 |
 Fri Jul 23 19:52:49 2010, Aidan, Computing, Hartmann sensor, Dalsa camera ADC 8th digitizer error
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I've attached an image that shows the locations of those pixels that record a number of counts = (2*n-1)*128.
The image is the sum of 200 binary images where pixels are given values of 1 if their number of counts = (2*n-1)*128 and 0 otherwise.
The excess of counts is clearly coming from the left hand tap. This is good news because the two taps have independent ADCs and it suggests that |
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Sat Jul 24 10:50:14 2010, Aidan, Electronics, Hartmann sensor, Lab Temperature and HWS temperature: pre-indium
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Hour-long trend puts the lab temperature at 19.51C
Dalsa temperature:
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Sun Jul 25 16:24:56 2010, Aidan, Computing, SLED, Superlum SLED test integrated with DAQ - new channel names
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I added some new channels to the Athena DAQ that record the diagnostic channels from the Superlum SLED.
C4:TCS-ATHENA_I_SET_VOLTS: - the set current signal in Volts (1V = 1A)
C4:TCS-ATHENA_I_ACTUAL_VOLTS: - a
signal proportional to the actual current flowing to the SLED (1V = 1A)
C4:TCS-ATHENA_I_LIM_VOLTS: - the current limit signal in volts (1V |
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Mon Jul 26 09:42:30 2010, Aidan, Computing, SLED, Long term test on SLED started - Day 0
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I set up the SLED to test its long term performance. The test began, after a couple of false starts, around 9:15AM this morning.
The output of the fiber-optic patch cord attached to the SLED is illuminating a photo-detector. The zero-level on the PD was 72.7mV (with the lights
on). Once the PD was turned on the output was ~5.50 +/- 0.01V. This is with roughly 900uW exiting the SLED. |
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Mon Jul 26 12:17:25 2010, Aidan, Electronics, Hartmann sensor, Added Indium to HWS
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I added some 0.004" thick indium sheet to the copper heat spreaders and and the heat sinks on the side of the HWS to try and improve the thermal
contact. Once installed the steady state temperature of the sensor was the same as before. It's possible that the surface of the copper is even more uneven
than 0.004". |
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Mon Jul 26 18:47:12 2010, James K, Misc, Hartmann sensor, Hex Grid Analysis Errors and Thermal Defocus Noise
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My previous eLog details how the noise in Hartmann Sensor defocus measurements appears to vary with ambient light. New troubleshooting analysis reveals
that the rapid shifts in the noise were still related to the ambient light, sort of, but that ambient light is not the real issue. Rather, the noise
was the result of some trouble with the centroiding algorithm. |
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Tue Jul 27 08:31:10 2010, Aidan, Electronics, SLED, Long term SLED test - Day 1
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The measurement from the on-board PD of the Superlum SLED seems to be falling. This effect started around 5PM last night which is right about the
time we moved the position of the PD that the SLED is illuminating on the optical table (via optical fiber).
Curiously, the current set point and delivered current to the SLED are dropping as well. |
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Wed Jul 28 18:32:12 2010, Aidan, Electronics, SLED, SLED long term test - Day 2
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Here's the data from the last 2 1/2 days of running the SLED. The decrease in photo-current measured by the on-board photo-detector is consistent with
the decrease in the current set-point and the delivered current, but it is not clear why these should be changing.
Strictly speaking I should add some analysis that shows that delta_PD_voltage_measured = delta_I_set_measured * [delta_PD_voltage/delta_I_set (I_set)]_calculated |
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Thu Jul 29 10:09:19 2010, Aidan, Electronics, SLED, SLED long term test - Day 2
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I've attached the Acceptance Test Report data from SUPERLUM for this SLED. I've also determined the expected percentage decrease in power/photo-current
per mA drop in forward current.
The measured decrease in forward current over the last 2 1/2 days is around 1.4mA from around 111mA. The expected drop in power is thus (4.5% per |
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Fri Jul 30 10:04:54 2010, Aidan, Computing, Hartmann sensor, Restarted the HWS EPICS channels
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Restarted the HWS EPICS channels on hartmann with the following command:
/cvs/opt/epics-3.14.10-RC2-i386/base/bin/linux-x86/softIoc -S HWS.cmd &
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Fri Jul 30 11:01:31 2010, Aidan, Computing, Hartmann sensor, EPICS softIoc alias
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I added an alias HWSIoc to controls which can be used to start the HWS EPICS softIoc.
alias HWSIoc='/cvs/cds/caltech/target/softIoc/startHWSIOC.sh'
and the bash script is:
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Fri Jul 30 13:38:39 2010, James Kunert, Computing, Hartmann sensor, Summary of Thermal Defocus Data Analysis
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Below is a table summarizing the results of recent thermal defocus experiments. The values are the calculated change in measured defocus per unit temperature
change of the sensor:
Experiment
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Fri Jul 30 19:22:24 2010, Aidan, Computing, EPICS, Waveform Channel Access for storing centroids
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A waveform channel was added to the HWS softIoc on hartmann. This allows arrays of data to be stored in a single channel. It's not clear whether
it is storing this data as a set of number or strings. However, the values can be changed by the following command:
caput -a -n C4:TCS-HWS_CENTROIDSX 5 1,2,3,4,5 |
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Fri Jul 30 21:19:05 2010, Aidan, Computing, EPICS, Waveform Channel Access for storing centroids
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After some discussion with Frank we figured out how to edit the record type in HWS.db so that the waveform/array channel actually behaved like a numerical
array and not like a single string. This just involved defining the data type and the element count in the record definition, like so:
record(waveform, "C4:TCS-HWS_CENTROIDSX")
{
field(EGU,"PIXELS")
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Sat Jul 31 11:54:20 2010, Aidan, Computing, SLED, SLED Test Day 5 - Re-tuned current set-point control voltage
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Main Points
Re-set SLED current set-point control voltage to 0.111V
SLED current set-point voltage drops by about 5mV when the SLED
is dis-engaged
Resetting was around 11:45AM PDT 31st-Jul-2010
I turned off the SLED for 10s and reset the current set-point |
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Wed Aug 4 09:57:38 2010, Aidan, James, Computing, Hartmann sensor, RMS measurements with Hartmann sensor
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[INCOMPLETE ENTRY]
We set up the Hartmann sensor and illuminated it with the output from the fiber-coupled SLED placed about 1m away. The whole arrangement was covered
with a box to block out ambient light. The exposure time on the Hartmann sensor was adjusted so that the maximum number of counts in a pixel was about |
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Mon Aug 9 10:58:37 2010, Aidan, Laser, SLED, SLED 15-day trend
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Here's a plot of the 15-day output of the SLED.
Currently there is an 980nm FC/APC fiber-optic patch-cord attached to the SLED. It occurred to me this morning that even though the patch cord
is angle-cleaved, there may be some back-reflection than desired because the SLED output is 830nm (or thereabouts) while the patch cord is rated for 980nm. |
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Tue Aug 17 22:34:14 2010, rana, Misc, General, ETM temperature after a 1W step
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This attachment is a Shockwave Flash animation of the iLIGO ETM getting a 1 W beam with a 3.5 cm radius getting fully absorbed onto the surface at t
= 0. |
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Wed Aug 18 18:38:11 2010, Aidan, Computing, Hartmann sensor, Hartmann sensor code
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I downloaded and tested revision 47 of the Adelaide Hartmann sensor code from the SVN (https://trac.ligo.caltech.edu/Hartmann_Sensor/browser/users/won/HS_OO?rev=47).
After giving it the correct input filenames it centroided the Hartmann sensor images pretty seamlessly. The output and code is attached below.
The code takes two Hartmann images. Locates the centroids in both instances and then determines the displacements of all the centroids between |
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Tue Aug 17 16:31:55 2010, Aidan, Things to Buy, Laser, Bought a laser diode from Thorlabs for HWS
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http://www.thorlabs.com/thorProduct.cfm?partNumber=CPS180
I bought this laser diode from Thorlabs today to try the current modulation trick Phil and I discussed last Friday.
That is: |
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Mon Aug 23 08:43:16 2010, Aidan, Things to Buy, Laser, Bought a laser diode from Thorlabs for HWS
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It arrived on Friday.
Quote:
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Mon Sep 13 18:24:52 2010, Aidan, Laser, Hartmann sensor, Enclosure for the HWS
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I've assembled the box Mindy ordered from Newport that will house the Hartmann sensor. It's mainly to reduce ambient light, air currents and to keep
the table cleaner than it would otherwise be.
We need to add a few more holes to allow access for extra cables. |
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Tue Sep 28 10:41:32 2010, Aidan, Laser, Hartmann sensor, Aligning HWS cross-sample experiment - polarization issues
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I'm in the process of aligning the cross-sampling experiment for the HWS. I've put the 1" PBS cube into the beam from the fiber-coupled SLED and
found that the split between s- and p-polarizations is not 50-50. In fact, it looks more like 80% reflected and 20% transmitted. This will, probably, be
due to the polarization-maintaining patch-cord that connects to the SLED. I'll try switching it out with a non-PM maintaining fiber. |
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Tue Sep 28 17:53:40 2010, Aidan, Laser, Hartmann sensor, Crude alignment of cross-sampling measurement
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I've set up a crude alignment of the cross-sampling system (optical layout to come). This was just a sanity check to make sure that the beam could successfully
get to the Hartmann sensor. The next step is to replace the crappy beam-splitter with one that is actually 50/50.
Attached is an image from the Hartmann sensor. |
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Wed Sep 29 16:49:36 2010, Aidan, Laser, Hartmann sensor, Cross-sampling experiment power budget
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I've been setting up the cross-sampling test of the Hartmann sensor, Right now I'm waiting on a 50/50 BS so I'm improvising with a BS for 1064nm.
The output from the SLED (green-beam @ 980nm) is around 420uW (the beam completely falls on the power meter.) There are a couple of irises shortly
afterwards that cut out a lot of the power - apparently down to 77uW (but the beam is larger than the detection area of the power meter at this point - |
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Mon Oct 4 19:44:03 2010, Aidan, Laser, Hartmann sensor, Cross-sampling experiment - two beams on HWS
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I've set up the HWS with the probe beam sampling two optics in a Michelson configuration (source = SLED, beamsplitter = PBS cube). The return beams from
the Michelson interferometer are incident on the HWS. I misaligned the reflected beam from the transmitted beam to create two Hartmann patterns, as shown
below. |
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Tue Oct 5 12:51:16 2010, Aidan, Laser, Hartmann sensor, Variable power in two beams of cross-sampling experiment
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The SLED in the cross-sampling experiment produces unpolarized light at 980nm. So I added a PBS after the output and then a HWP (for 1064nm sadly) after
that. In this way I produced linearly p-polarized light from the PBS. Then I could rotate it to any angle by rotating the HWP. The only drawback was that
the HWP was only close to half a wave of retardation at 980nm. As a result, the output from this plate became slightly elliptically polarized. |
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Thu Nov 4 13:31:19 2010, Won Kim, Computing, Hartmann sensor, Frame Grabber SDK installation
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Appended below is the step by step procedure that I used to
install and
use the frame grabber SDK. Note that the installation |
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Tue Nov 23 06:15:08 2010, Won, Computing, Hartmann sensor, Image folder structure
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Attached below is a diagram that describes the organisation of image folders that I am using at the moment with Run_initialize and Run_acquire scripts.
Once the uppermost folder 'image' is set up, other folders in it will be created by the matlab codes if not present. Still it may be of less hassle
to create the folders beforehand. |
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Tue Nov 30 11:01:19 2010, Aidan, Computing, General, New workstation added in TCS Lab. New Static IP
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| I added a workstation at 10.0.1.26 in the TCS lab. |
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Tue Nov 30 11:03:19 2010, Aidan, Computing, Frame Grabber, EDT frame grabber works under Ubuntu
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The new machine in the TCS lab is running Ubuntu. I installed the frame-grabber into it and, after loading the configuration file for the camera, was
able to access the serial port on the camera and also was able to record a properly formatted image from the Hartmann sensor. |
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Tue Jan 25 16:38:16 2011, Aidan, Electronics, Pre-amplifier, L1 TCSY ISS Board transfer function
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I measured the AC and DC channel transfer functions of the eLIGO L1 TCSY ISS board for PD1 and PD2. The gain is quite high on the AC channels so
I added +40dB of attenuation to the source from the SR785. As Frank pointed out, even though this isn't exactly +40dB at low frequencies, it still attenuates
and that attenuation is common to both the input to the Channel 1 of the SR785 and the input to the ISS board. |
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Tue Feb 8 13:02:26 2011, Aidan, Electronics, Delivery Note, Thorlabs S322C 200W power head arrived
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| The 200W Thermopile power head from Thorlabs arrive today. The scanned delivery note and calibration info are attached. |
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Fri Feb 18 14:53:50 2011, Phil, Laser, Laser, LTG laser delivering specified power
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I got the LTG CO2 laser to deliver 50.02W as measured by the Thorlabs 200W power head today. This required running the Glassman HV supply at full power
(30.0kV, 31.1mA), tweaking the end grating and output coupler alignments, and cleaning the ZnSe Brewster windows on the laser tubes, and it only lasted
a few seconds before dropping back to ~48W, but the laser delivered the specified power. In the factory it delivered 55W at the 10.6 micron line I am using |
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Fri Feb 18 13:26:23 2011, Aidan, Things to Buy, Delivery Note, First parts of Bosch framing have arrived from Valin
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The first pieces of the Bosch framing have arrived from Valin Corporation. These are just small pieces such as the fasteners and the gussets. There are
no custom lengths of framing yet.
The details are in the attached Packing List. [1:25PM] I haven't verified that everything is there yet. |
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Wed Feb 23 18:04:38 2011, Aidan, Things to Buy, Delivery Note, First parts of Bosch framing have arrived from Valin
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Quote:
The first pieces of the Bosch framing have arrived from Valin Corporation. These are just small pieces such as the fasteners and the gussets. |
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Wed Feb 23 20:18:30 2011, Aidan, Electronics, Hartmann sensor, Successfully re-started the Hartmann sensor
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I reattached the Hartmann Sensor to the LENOVO machine that is running Ubuntu and turned it on (it's been disconnected for a couple of months).
The /opt/EDTpdv/serial_cmd was able to communicate successfully with the camera. |
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Thu Feb 24 10:23:31 2011, Christopher Guido, Laser, Laser, LTG initial noise
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Cheryl Vorvick, Chris Guido, Phil Willems
Attached is a PDF with some initial noise testing. There are 5 spectrum plots (not including the PreAmp spectrum) of the laser. The first two are
with V_DC around 100 mV, and the other three are with V_DC around 200 mV. (As measured with the 100X gain preamplifier, so ideally 1 and 2 mV actual) We |
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Thu Feb 24 13:35:41 2011, Aidan, Things to Buy, Delivery Note, Bosch framing has arrived
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The custom pieces of the Bosch framing have arrived. Transportation is currently moving them downstairs to the lab. The packing list is attached.
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Thu Feb 24 14:20:55 2011, Aidan, Misc, Ring Heater, aLIGO H2 Ring Heater Pics
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Here are some pictures of the ring heater segments destined for the H2 Y-arm this year.
These still need to be put onto ResourceSpace. |
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Thu Feb 24 14:23:58 2011, Aidan, Lab Infrastructure, Hartmann sensor, Hartmann Sensor box cut down to size
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I reduced the height of the Hartmann sensor box. This is what it looks like now:
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Tue May 4 13:35:13 2010, Aidan, Computing, Hartmann sensor, Hartmann temperature channels in frame builder
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I've added the digitizer and sensor board temperature readings from the HWS to the frames. This was done in the following way
1. Create a new file /cvs/cds/caltech/chans/daq/C4TCS.ini - with the channels in it - see below
2. open /cvs/cds/caltech/target/fb1/master |
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Mon Feb 28 17:33:07 2011, Aidan, Computing, Hartmann sensor, Hartmann Seidel abberation channels in frame builder
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Using the same methods as before, see below, I've added some Hartmann sensor EPICS channels to the frames.
The channels record the Hartmann sensor Probe (and Secondary) Coefficients of the Seidel aberrations (PSC, SSC) that are specified (PRISM, ALPHA,
PHI, etc). |
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Mon Feb 28 17:56:32 2011, Aidan, Computing, Hartmann sensor, Got HWS code running and interface to EPICS
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Here are the notes from today's efforts:
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