40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Authorup Type Category Subject
  8849   Mon Jul 15 16:44:46 2013 AlexUpdateOMCOMC North Safety

 [Eric Alex]

We are planning on testing our laser module soon, so we have added aluminum foil and a safety announcement to the door of OMC North. The safety announcement is as pictured in the attachment.

Attachment 1: photo_2_(1).JPG
  8850   Mon Jul 15 16:51:37 2013 AlexConfiguration Planned AS Table addition

 [Eric, Alex]

We are planning to add our reference PD to the southern third of the AS Table as pictured in the attachment. The power supply will go under the table.

Attachment 1: AS_Table_Ref_PD_Addition.pdf
  17422   Wed Jan 25 16:58:19 2023 AlexUpdateCamerasRecording CCD cameras

Thus far, the software needed for the Magewell video encoder has been successfully installed on Donatella. OBS studio has also been installed and works correctly. OBS will be the video recording software that can be interfaced via command line once the SDI video encoder starts working. (https://github.com/muesli/obs-cli)

So far, the camera can not be connected to the Magewell encoder. The encoder continues to have a pulsing error light that indicates "no signal" or "signal not locked". I have begun testing on a secondary camera, directly connected to the Magewell encoder with similar errors. This may be able to be resolved once more information about the camera and its specifications/resolution is uncovered. At this time I have not found any details on the LCL-902K by Watec that was given to me by Koji. I will begin looking into the model used in the 40 meter next.

  17441   Wed Feb 1 16:53:55 2023 AlexSummaryGeneralShadowing Anchal on developing a change for the c1ioo CDS computer

During my time shadowing Anchal, we discussed the need for digital control systems on the suspension systems for the 40 meter optics. The controls and diagnostics system (CDS) allows us to develop our own feedback controls and filters for the suspension systems by taking in analog signals from the shadow sensors. The feedback control system developed in the CDS then utilizes the OSEM actuators to dampen harmonic motion and noise on the suspension lines. While improving these feedback loops is an ongoing challenge, it is a problem that is likely non-linear, meaning the system must be understood on a much higher level to make further improvements. This brings us to the new addition of a wavefront sensor in the 40m lab, which will allow for constant monitoring of the active wavefront in the interferometer. The wavefront will soon be used for gathering training data for a neural net that will help further analyze the non-linear effects within the suspension and damping system. What Anchal was working on today was an update within a CDS model for clioo to allow for the integration of the wavefront sensor such that he may use a switch to change between connections in the mode cleaner and the arm cavity. The CDS models may be edited and updated using Matlab/Simulink to arrange blocks and code in a robust and visual manner. The final system designed in Simulink can then be saved and compiled using the real-time code generator (RCG), which cross-compiles the Simulink file into C code that can be read by the CDS system to assign inputs, outputs, and various logic or algorithms for filtering.

  17459   Thu Feb 9 11:07:38 2023 AlexUpdateCDSAdding callibration filters to c1sus

Today I updated the ETMY suspension model to include 4 new filters at the output of the position, pitch, yaw and side summers and before the "To Coil Matrix". The library that was changed and updated is "sus_single_control_new". These callibration filters are labeled in the orange box as POSCAL, PITCAL, YAWCAL, and SIDECAL. The four filters are important as the will allow us to callibrate the position and side from counts to micro meters, and pitch and yaw from counts to micro radians.

The next steps for utilizing this update will be

    - create a few experiments to find the callibration constants for the 4 degrees of freedom

    - edit and update the ETMY Suspension screen to include selectable filter boxes to implement the callibration constants


For future reference, preform the update and restore the models to their previous states you may use the following:

to install the models we ssh into the computers running the ETMY suspension models (for example)

     ssh c1sus

then for each model using the suspension library (we used c1sus c1mcs c1scx c1scy c1su2 c1su3) do

     rtcds build-install c1sus

the watchdogs will need to be shut down for c1sus and the model will need to be restarted next

     rtcds restart c1sus

Now we restore the filter values to the last saved point (about an hour before the update) in cds folder

     python burtRestoreRTSepics.py -m c1sus c1mcs c1scx c1scy c1su2 c1su3 -o 10

Last we reset the watchdogs again using the following script in SUS>medm

     python resetFromWatchdogTrip.py MC1 MC2 MC3 BS PRM SRM ITMX ITMY ETMX ETMY

  17471   Thu Feb 16 23:54:11 2023 AlexUpdateDaily ProgressYaw and Pitch Calibration constants for ETMY op-lev

This work was done by Ancal and I. 

To recallibrate the op-lev for ETMY, a python script was first written to calculate the change in distance in x or y that the photodiode array will see when the mirror incurs a change in yaw or pitch. The python script approximates d by integrating, using a reimann sum, the area under a gaussian curve, given by I(r)= Iexp(−2r2/ 2w(z)2), where r is the radial position, and w(z) is the waist (radius) size of the gaussian beam where power reaches 1/eof its maximum. The distance d, is the difference from the center of the gaussian to the point at which the beam profile has a normalized area under the curve equal to that of the percent of the beam profile showing on one half of the circular photodiode array.

     Above, the gaussian is related to the translation of the beam profile on the photodiode where the area calculated under the curve of the gaussian, is equivalent to the ratio of the beam profile in 2 adjacent quaters of the photodiode array. 

The gaussian, is directly related to the waist size of the laser beam profile, and thus a beam profiler was used to calculate the waist size over an average of 100 takes. Due to the thickness of the beam profiler, we were unable to get a direct measurement of the size of the beam at the exact location of the photodiode. Instead, we took two seperate measurements while moving the profiler 1 inch further away from the photodiode and back calculated the average size of the beam at the photodiode assuming that at this distance away from the source, the beams width would expand linearly. This provided a 2*waist size of 1625 ± 40 um. 

     image above displays the laser beam profiler used to approximate the waist size of the op-lev laser.

The physically calculated translation of the beam profile, d, can then be used to determine the overall angle, theta, that the mirror has moved to create this offset. The relation between distance and theta is Theta = d/2R, where R is the length from the mirror surface to the photodiode. R was then measured by hand over the optics table, and estimated to the best of our ability using the accurate autocad drawings of ETMY. This provided us with an R length of 1.76 ± 0.02 meters. 

     Image above shows the current system in place for converting the photodiode counts into microradians. The calibration constant is implemented at the last green filter boxes for pitch and yaw. 

Lastly, to calculate the callibration constants, a series of tests were run on the ETMY suspeneded mirror. First, a time averaged value of the photodiode counts was taken with the mirror locked in place. Next, pitch and yaw were adjusted by 10 counts seperately, and the photodiode outputs recorded. This was done again but by moving the mirror 50 counts in pitch and yaw (seperately). The final result of the difference of the calculated theta values over the difference of pitch or yaw counts provided the following callibration constants:

      Pitch moved +10 counts: 131 ± 5 cts/urad

      Pitch moved +50 counts: 155 ± 5 cts/urad

      Yaw moved +10 counts: 237 ± 5 cts/urad

      Yaw moved +50 counts: 241 ± 5 cts/urad

Given our results, we believe that the values found for our 50 count translation to be the best approximation of the calibration constant due to its movement being more significant than that of the change seen from adjusting yaw or pitch by only 10 counts. 

Next steps will be to update the values in the controls system and improve the python script to be more autonomous rather than a a step by step calculation. 


  17477   Wed Feb 22 23:40:48 2023 AlexUpdateCalibrationAdding calibration constants for sus matrix and filter control buttons to the sus control screen

The callibration constants were updated for the oplev pitch and yaw. The values were changed as denoted in 17471 were:

     PITH: 175.7→ 155 cts/urad

     YAW: 193 → 241 cts/urad

To make these changes for the oplev callibration constants I went to ETMY - SELECTED OPLEV SERVO BOX

I then opened OLMATRIX and turned off PITCH and YAW servos in the ETMY SUSPENSION SCREEN such that the system does not attempt to actively make corrections while values are being changed. 

Then I adjusted the matrix to include our updated calibration constants and reinitiated the oplev ptich and yaw servo's

This updated the calibration constants for everything


The next change that was made was the addition of the calibration filters for position, pitch, yaw and side into the sitemap view for the suspension systems.

Adding calibration filters will allow us to callibrate the pos, pitch, yaw, and side to true values of urad and umeters (see 17459)

The final screen may be seen bellow (the updated area is outlined in red):


When each of the filter buttons is clicked, the following screen will now appear (circled in yellow is the calibration constant gain we will be calculating and entering into the system):


To create the edits to the controls screen we must complete the following process

We can edit the original screen - right click > evaluate > edit this screen

Then I adjusted the width of the overall screen, and moved the right half of the modules over to the right so I could fit in some filter buttons. I then Navigated to the c1ioo wfs master screen using the open feature to copy a pre existing filter module

I then adjusted the filter module and its contents to correspond to the features and autogenerated model files from RTCDS

There was some rearranging and adjusting needed to get these files in place first. The autogenerated files from the RTCDS can be found in dir = "/opt/rtcds/caltech/c1/medm/c1sus/"

They were autogenerated with names "C1SUS_BS_PITCAL.adl", "C1SUS_BS_POSCAL.adl", "C1SUS_BS_YAWCAL.adl","C1SUS_BS_SIDECAL.adl" 

We copied these files to dir = "/opt/rtcds/userapps/trunk/sus/c1/medm/templates/NEW_SUS_SCREENS/"

The file names were changed to "SUS_PITCAL.adl", "SUS_POSCAL.adl", "SUS_YAWCAL.adl", "SUS_SIDECAL.adl" 

The directory we placed them in is where the models for c1 sus can be found that are referenced by the sitemap suspension monitor screen

Each file was then opened in Vscode and a few changes were made such that the specific naming values referenced by the different screens of the sitemap and different optics, are replaced by the overarching values seen in each instance of the screens.

There are approximately 50 referenced file names of "C1:SUS-BS_PITCAL" etc. In each instance we made the following changes:

"-BS" was changed to "-$(OPTIC)"

"C1:" was changed to "$(IFO):"

The new strings should read "$(IFO):SUS-$(OPTIC)_PITCAL"

Once this change was made we can now right click on the filter module box, click on "Label/Name/Args" button

In the display file, we must add the path name for the calibration directory "/opt/rtcds/userapps/trunk/sus/c1/medm/templates/NEW_SUS_SCREENS/SUS_POSCAL.adl"

And for the arguments box we will enter OPTIC=$(OPTIC), IFO=$(IFO)

You can also copy and paste the directory names in the file boxes using right click copy from the file manager and paste into the box using a single click of the mouse scroller wheel

Lastly, the PV limits were changed for each number output right click value box > PV limits > Precision > Source changed to "Default" with a value of 1.

The shown value of the position, pitch, yaw, and side was then changed to show the output from the newly added filter. This is done also by right clicking the value box and adjusting the "Readback Channel".

Value changed from "$(IFO):SUS-$(OPTIC)_TO_COIL_1_#_INMON" to the outputs from the filters which are

       "$(IFO):SUS-$(OPTIC)_POSCAL_OUTMON" (for others changing POSCAL to the appropriate variable)

This is how to edit and add the Medm screens for single suspension optics into the sitemap IFO SUS screen


Lastly, Tomohiro and I worked on acquiring 6 data sets from DC stepping through adjustments in pitch and yaw for MC1, MC2 and MC3. These datasets will be fit quadratically and combined with more tests dine by AC driving the stepper motors tomorrow to find the calibration constants for the mirrors.

Attachment 2: InkedScreenshot_2023-02-22_18-28-41.jpg
Attachment 3: InkedScreenshot_2023-02-22_18-29-00.jpg
  17481   Fri Feb 24 13:29:16 2023 AlexSummaryIMCUpdated angular actuation calibration for IMC mirrors

Also reply to: 40m/17352

Tomohiro, Anchal, and I did the following to make updates to the calibration constants for pitch and yaw on MC1, MC2 and MC3.

To acquire the data used for fitting a curve respective to the change in counts per change in mirror pitch and yaw, we utilized some code that Anchal has already developed.

The scripts used to take time averaged data points of the IMC mirrors can be found by entering the command $ s into a terminal window to enter the scripts folder. Then enter the path "SUS/angActCal"

The following scripts will be found there to be used for this experiment:

angActCal.py & parabolaFit.py

To take data we used the angActCal.py function with set values for the time averaging = 5 s, settle time = 5 s, and adjusted the offset such that we would acquire approximately 20 data points given our ASC Bias limits. We defined the limits for each plot based on where the transmission fall off from the maximum value reached an average range of 10,000 counts.

The "readChannel" for each was the "C1:IOO-MC_TRANS_SUMFILT_OUTPUT" and can be found from the site map at IOO>Lock MC> see MC2_TRANS

The adjustment channels for Pitch and yaw on each IMC mirror were entered as the offset value found in the IMC screen at ALIGNMENT OFFSETS > BIASPIT/BIASYAW > OFFSET

For the code to work, the offset switch must be turned on. parabolaFit.py 

The data from MC1, MC2, and MC3 for pitch and yaw was saved to individual text files which were then entered into the parabolaFit.py function to get the results seen in attachment 1 and 2.


The above images show the printout from the plot fitting function and one of the graphs produced.

Optic ACT

Fit curve factor for DC (1/cts^2)


2.41 +/- 0.01 e-3


4.12 +/- 0.02 e-3


5.75 +/- 0.03 e-3


8.48 +/- 0.13 e-3


1.83 +/- 0.03 e-3


4.52 +/- 0.05 e-3

From the fitted curve values we then derived the equations that will soon be described further by Tomohiro (see entry _____) to arrive at the final callibration constants.


Optic ACT

Callibration constant at DC (urad/cts)


12.66 +/- 0.03


6.64 +/- 0.02


lock6.83 +/- 0.02


4.69 +/- 0.04


11.03 +/- 0.09


6.96 +/- 0.04

Final Calibration Constants for MC1, MC2, & MC3


We then utilized our calculated calibration constants (as seen bellow) to adjust the following filter parameters in the IMC control panel.


To make the updates such that the IMC screens show the correct urad values at the output of the filter banks, we must do the following steps to MC1, MC2, and MC3:

First, to make changes to our calibration filters, we must first shut off the pitch and yaw feedback loop controls.

TO do so for the Lock Filters, we will set the pitch and yaw SUS ASC inputs to 0 but entering the sitemap > IOO > C1IOO_WFS_MASTER

Nex head to action at the top right, and we can select "MC WFS relief 60s", this will relieve the values from the pitch and yaw inputs to the 40m Mode Cleaner Alignment settings to save the overall alignment and allow us to turn off the WFS servos to make the necessary adjustments on the lock filters.

Once we have waited a sufficient amount of time for the values on the ASC inputs to hover around 0, select Turn WFS ON/OFF button and choose "Turn OFF MCWFS Servo"


Next, we will press on the "on/off" button (see attachment 3 - circled in orange) for pitch and yaw found in just the LOCK FILTERS windows.

Once these are off we will stay in the same screen and adjust the gain values (boxed in yellow) for pitch and yaw.

Next, we will take the current value and divide it by the newly found corresponding calibration constant. This is to adjust for the changes we will be making on the output end of the filter banks such that all values in the feedback controls are normalized to the same scale.

The changes made here can be seen bellow:


Damp Filter Orig

Damp Filter NEW

Lock Filter Orig

Lock Filter New
































Now that these changes have been made in the damp and lock filter banks, with the pitch and yaw feedback loops STILL OFF, we may adjust the newly made calibration filters for pitch and yaw (as seen in attachment 4).

The "P" and "Y" filters may be opened (boxed in red) and we may adjust the gain (circled in yellow). Because each of these filters have just been created, the value is set to 1. This value can be completely replaced with the calibration constant found in our table above. Thus we will now change MC1 Pitch to have a "gain" of 12.66 and so forth.

Once each of the calibration filters have been updated, you may go back into the damp filters and reinitiate the feedback loops.

Once all values have been entered,

This concludes the updating of the IMC filter calibration constants at DC.

Attachment 1: angActCal_C1-SUS-MC1_BIASPIT_OFFSET_to_C1-IOO-MC_TRANS_SUMFILT_OUT_1361152703.png
Attachment 2: Screenshot_2023-02-23_16-47-58.png
Attachment 3: InkedScreenshot_2023-02-23_17-02-13.jpg
Attachment 4: InkedScreenshot_2023-02-23_17-02-49.jpg
  17484   Sun Feb 26 00:13:55 2023 AlexConfigurationASCIOO MC PIT/YAW gain change

The following changes were made to the WFS MASTER IMC Pitch and Yaw gains:

Gain values for the pitch and yaw on MC1, MC2, and MC3 filters on the SUS ASC inputs have been carried over to the WFS MASTER output filters.
This was done such that Tomohiro and I could take AC measurements at an oscillation freq of 77 Hz on the pitch and yaw mirrors, while being sure that the amplitude of the AC signal being applied to each mirror is the same. The filters on the WFS output will have gains changed from 1.0 to the previously mentioned calibration values described in ELOG 17481

The values calculated for each filter were inverses of the callibration constants. The filters at the SUS ASC inputs were modified to read gain values of 1.0 again.
See the table bellow for the values passed to each filter.
In summary:
originally IOO-MC1,2,3_PIT/YAW_GAIN = 1.0. Now:



IOO-MC1,2,3_PIT/YAW_GAIN >> 1.0

  17486   Wed Mar 1 17:13:38 2023 AlexUpdateIMCTransfer Function for IMC mirrors using sine sweep

The following work has been done by Tomohiro, Anchal and I:

To acquire the transfer functions for each of the IMC mirrors, we utilized diaggui, the CDS Diagnostic Test tool. We would like to measure the open loop transfer function, which is the ratio of In1 and In2, corresponding to before and after the injection point of the excitation signal.

A sinusoidal excitation signal was swept from 0,2 Hz to 5 Hz and includes 11 data points from an average of 10 cylcles per point.

NOTE: the WFS gain must be adjusted from 1.0 to 4.0 for these measurements (this is the slider underneath the "Turn WFS ON/OFF" button in C1:IOO_WFS_MASTER.

For the three sets of data taken for Pitch in WFS1, WFS2, and MC2 Trans, the amplitude of the excitation wave was 30,000.

In each measurement, the injection point is "C1:IOO-X_EXCMON", where X is the WFS or MC2 + Pitch or Yaw.


We will be conculding our measurements tomorrow and will report the findings for YAW in WFS1, WFS2, and MC Trans2.

Attachment 1: WFS1_PIT_OLTF.pdf
Attachment 2: WFS2_PIT_OLTF.pdf
Attachment 3: MC2_TRANS_PIT_OLTF.pdf
  17500   Thu Mar 9 10:29:15 2023 AlexUpdateIMCStep response test on MC1, MC2, and MC3 YAW

Tomohiro, Anchal and I completed the following processs for acquiring a new Output Yaw matrix for the "C1IOO_WFS_OUTMATRIX".

To did this by following the same process in 17493 but instead of adding our offsets in the WFS1, WFS2 and MC Trans filter banks, offsets were added at the end of the feedback loop at the optics, MC1, MC2 and MC3 YAW.

Optimal offset values were found such that the offset change did not disrupt the output WFS transmission signal by more than about a one thousand counts. Each limit was set to come close to this limit.

Our final offset values were:


Offset Value

MC1 55
MC2 15
MC3 35

The step response was than observed in Diaggui, but the entire 800 s run was unable to be viewed at once. We then utilized our python script from the previous step response data that we took to develop the following:

The measured response from stepping the optics was:

\begin{pmatrix} 1.31\pm0.24 & 54.2\pm1.3 & -0.28\pm0.03\\ -2.13\pm0.23 & -20.7\pm1.6 & 1.11\pm0.03\\ 1.82\pm0.27 & -25.8\pm1.5 & 0.16\pm0.03\\ \end{pmatrix} \begin{pmatrix} MC_{1Y}\\ MC_{2Y}\\ MC_{3Y}\\ \end{pmatrix} = \begin{pmatrix} WFS_{1Y}\\ WFS_{2Y}\\ MC_{2Y-TRANS}\\ \end{pmatrix}

*The values in this matrix represent the number of counts/offset count. Thus all ovalues found from the step response were divided by the number of counts on each offset.

To find the new yaw matrix, we then take the inverse of the step response output matrix to get:

\begin{pmatrix} MC_{1Y}\\ MC_{2Y}\\ MC_{3Y}\\ \end{pmatrix} = \begin{pmatrix} 0.188 & -0.009 & 0.403 \\ 0.017 & 0.005 & -0.006 \\ 0.689 & 0.987 & 0.656 \end{pmatrix} \begin{pmatrix} WFS_{1Y}\\ WFS_{2Y}\\ MC_{2Y-TRANS}\\ \end{pmatrix}

The results from the step response may also be seen graphically in attachment 1. The first plot shows all 3 response signals. Then each following plot shows the individual signals and the step responses overlayed for each one.

The plots also include horizontal lines that represent the average for the stepped signals and the average of the signal at rest along with shading for their associated uncertainties.


This was then tested in C1IOO_WFS_BASIS Yaw matrix, and at first did not work well. The WFS1 Yaw output would rail toward the limits. To fix this, the sign of the gain was flipped (from 0.5 to -0.5) which seemed to solve this issue.

This was then transmitted to the matrix to give:

\begin{pmatrix} MC_{1Y}\\ MC_{2Y}\\ MC_{3Y}\\ \end{pmatrix} = \begin{pmatrix} -0.188 & -0.009 & 0.403 \\ - 0.017 & 0.005 & -0.006 \\ -0.689 & 0.987 & 0.656 \end{pmatrix} \begin{pmatrix} WFS_{1Y}\\ WFS_{2Y}\\ MC_{2Y-TRANS}\\ \end{pmatrix}

This did not solve all issues, the overall ouput signals from the WFS filters still seemed to have large fluctuations. I then began adjusting the gains of the WFS1, WFS2 and MC Trans yaw output filters and achieved much steadier signals.

The following table describes the current best gain valuse for our Yaw matrix:

Sensor Gain Value
WFS1 YAW 5.94
WFS2 YAW 6.44

The results from our found matrix and gain changes can be seen on the left of attachement 2 that displays the ouputs on the Error Signal Monitor. The original output yaw matrix signals can be seen on the right hand side. There is work to still be done on adressing these issues, but overall this may be improved by some additional changes in the gains on each channel.

Attachment 1: step_response_080323.pdf
Attachment 2: Screenshot_2023-03-08_18-17-35.png
  17501   Thu Mar 9 14:22:24 2023 AlexUpdateComputer Scripts / ProgramsUpdate to toggleWFSoffsets.py for step response testing

I have pushed changes made to the toggleWFSoffsets.py script to the git.

This file may be found in: "/opt/rtcds/caltech/c1/Git/40m/scripts/MC/WFS/"

The changes made are:

Updated the script to allow for toggling step responses on either optics or sensors (default = optics), chosen by user

The script orignally asked user to make any last changes to the offsets before hitting enter to run without displaying the new changes.

Now the script checks for changes made by the user to the offsets and displays them if detected. If no changes are made, the code starts running the steps.



  17505   Mon Mar 13 15:37:13 2023 AlexUpdateIMCStep Response of newly diagonalizing YAW output matrix

From the work that Anchal has completed for diagnolizing the YAW ouput matrix, a step response was taken of this new matrix using our previous methodolgies and the following results:

The step response can be seen plotted in attachment 1. The off diagonal terms of this new matrix sum to 1.24, which is a large decrease from the current matrix and the matrices that were tested from our previous step responses. 

Tomohiro and I are now currently working futher to configure the UGF's for YAW given this new output matrix.


Tomohiro and I have completed testing the YAW Sensor outputs with broadband noise injection and have confirmed that gains currently set on each filter module (which is 1.0 for WFS1, WFS2, and MC Trans) provides us with adequate UGF's. As seen bellow in attachment 2-3, WFS1 and WFS2 have UGF's between 2 and 3 Hz. MC Trans can be seen in attachment 4 and has been confirmed to have a UGF around 0.1 Hz.

Finally, attachment 5 displays the off diagnolized sums and uncertainties for each of our previous step response results and the newest result (labeled "new") for Anchal's OUTPUT YAW matrix. The first graph in blue displays the overall sum and uncertainty related to each step response taken. Then in the following 3 plots, the sum's and uncertaintes for each sensor are displayed individually for each step response test.

For reference:

New: corresponds to Anchal's YAW OUPUT MATRIX

D0: refers to the previously implemented matrix, prior to any testint or updates

D1: refers to the matrix that was computed based off of the first test Tomohiro and I performed

D2: refers to the matrix computed as a secondary result from D1. This matrix was thought to provide a lower off diagonal sum, but did not.

This thoroughly displays our results such that the newly computed matrix from Anchal is much more diagnolized then that of the step response matrices Tomohiro and I have computed.


Attachment 1: step_response_YAW_130323.pdf
Attachment 2: WFS1_YAW_OLTF_NI.pdf
Attachment 3: WFS2_YAW_OLTF_NI.pdf
Attachment 4: MC2_YAW_OLTF_NI.pdf
Attachment 5: Mar13_Dfactor.pdf
  17507   Tue Mar 14 11:34:05 2023 AlexHowToComputer Scripts / ProgramsSummary Pages Restart

If the summary pages go down, it could be from a break in the script or some small error. The first remedy for fixing this can be to remove the cron jobs in the que and restart the "gw_daily_summary.sub" and "gw_daily_summary_rerun.sub" scripts. 

For more information on how to do this, follow instructions found in the wiki.


  17515   Tue Mar 21 18:41:12 2023 AlexUpdateIMCDither Lines set on MC1, MC2, MC3 for the night

With Anchal's help, I have setup dither lines for Rana on MC1,2,3 that will be running overnight. The oscilations were set on MC1,2,3, oscillator screens.
The following table describes the current setup:

Mirror Frequency Amplitude
MC1 21.12 Hz 2000
MC2 25.52 Hz 1000
MC3 27.27 Hz 2500

These frequencies and amplitudes were set on LOCKIN1 for each MC1,2,3. The output filters matrix for MC1,2,3 was also updated to reflect the degree of freedom being tested: PITCH.

The frequencies were picked to avoid the dewhitening frequency: 28Hz, and the Bounce/Roll frequencies: 16 Hz & 24 Hz. Furthermore, decimal value frequencies were utilized to avoid the multiples of 1 Hz.

The oscilators were originally started at 1363480200 and will be turned off at 1363535157.

See attachment 1 for the plot of the power spectrum. This test is done to find the beam offset for pitch.

Attachment 1: 21032023_Dither_lines_plot
  17516   Wed Mar 22 15:51:44 2023 AlexUpdateIMCBeam offset calculation for MC1,2,3 from dither results

I have organized the resulting data from running dither lines on MC1,2,3. The data has been collected from diaggui as shown in attachment 1.

Mirror f_l Avg Re (+/- 1000) Avg Im (+/- 1000) Peak Power (\delta f) Cts/urad
MC1 21.12 7000 4000 8062 12.66
MC2 25.52 13000 10000 16401 6.83
MC3 27.27 4000 -600 4044 11.03

Next using the following equations we can find \Delta Y:

\Delta L = \Delta Y \cdot \theta_{AC}

Where \Delta L is the change in length in result of the dithering and \Delta Y is the overall change in beam spot position

Delta L can be calculated by:

\Delta L = \frac{\delta f}{v_{laser}} \cdot L_{IMC}

where \delta f is the peak power of the line frequency and is found by taking the square root of the magnitude of the Real and imaginary terms, v_{laser} is frequency the laser light is traveling at (281 THz) and L_{IMC} is the lenght of the IMC (13.5 meters).

\theta_{AC} can then be calculated by:

\theta_{AC} = \theta_{DC}/f_l^2

where  \theta_{AC} is the angle at which the mirror was shaken at a given frequency. We can find \theta_{DC} by converting the amplitude of the frequency that the mirror was shaken at and converting it into radians using the conversion constants found here: 17481.

\theta_{AC} is then shown to be found by this angle diveded by the line frequency.

The final values are calculated and displayed bellow:

Mirror \theta_{DC} \theta_{AC} \Delta L \Delta Y
MC1 157.9 urad 0.35 urad 0.38 nm 1.08 mm
MC2 146.4 urad 0.23 urad 0.78 nm 3.39 mm
MC3 226.7 urad 0.31 urad 0.19 nm 0.61 mm


Attachment 1: 22032023_Dither_lines_demod_MC1_21-12.pdf
22032023_Dither_lines_demod_MC1_21-12.pdf 22032023_Dither_lines_demod_MC1_21-12.pdf
  8859   Tue Jul 16 17:02:41 2013 Alex ColeConfigurationElectronicsAS Table Additions

 [Eric, Alex]

We added our reference photodetector (Newport 1611, REF DET) to the southern edge of the AS table, as pictured. The detector's power supply is located under the southwest corner of the table, as pictured. We have connected the detector to its power supply, and will connect the detector's fiber input and RF output tomorrow.

EDIT: this is about the RFPD frequency response setup...

Attachment 1: photo_1_(1).JPG
Attachment 2: photo_2_(2).JPG
  8862   Wed Jul 17 11:13:36 2013 Alex ColeConfigurationElectronicsAS Table Additions

[Eric, Alex]

For the RFPD frequency response project, we routed the fiber that will connect our REF DET (on the AS table) to our 1x16 optical splitter (in the OMC_North rack), as pictured. (The new fiber is the main one in the picture, which ends at the right edge near REF DET) Note that we secured the fiber to the table in two places to ensure the fiber would remain immobile and out of other optical paths already in place.

At 2:00 we plan to run fiber from our laser module (in rack 1Y1) to our 1x16 optical splitter (in the OMC_North rack) and measure the power output at one of the splitter's output ports. We plan to keep the output power limited to less than 0.5 mW per optical splitter output.

Attachment 1: photo_(1).JPG
  8863   Wed Jul 17 16:15:42 2013 Alex ColeConfigurationElectronicsAS Table Additions

[Eric, Alex]

We decided that the POY Table would be a better home for our REF DET (Newport 1611 FC-AC) than the AS Table. We moved the PD to the POY Table (1st attachment) and routed a fiber from our 1x16 Optical Splitter in the OMC_North rack to the POY Table. REF DET's power supply is now located under the POY table (2nd attachment). We left the fiber described in the previous post on the AS Table.

Afterwards, we hooked a fiber up to our laser module to test it (3rd attachment). The laser was not being distributed, just going to one fiber with a power meter at its end. Everything turns out, but we realized we need to read the power supply's manual before continuing. 



Attachment 1: photo_1_(3).JPG
Attachment 2: photo_2_(3).JPG
Attachment 3: photo_3.JPG
  8870   Thu Jul 18 15:34:15 2013 Alex ColeUpdateElectronicsPD Frequency Response Update

 [Eric, Alex]

Our RF Switch arrived today, and we mounted it in rack 1Y1 (1st attachment). 

We connect our input fiber and all of our output fibers to our 1x16 optical splitter (2nd attachment). Note that the 75 meter fiber we are using for the splitter's input is in a very temporary position (3rd attachment - it's the spool).

We successfully turned our laser on and tested the optical splitter by measuring output power at each fiber using our Thorlabs PM20 power meter. Data was taken with the laser running at 67.5 mA and 24 degrees Celsius:

Detector name                  Power

REF DET 192 µW
AS55 146 µW
REFL55 180 µW
REFL11 172 µW
REFL33 146 µW
REFL165 180 µW
POP22/POP110 182 µW
POP55 193 µW
POX11 123 µW



Attachment 1: photo_3_(1).JPG
Attachment 2: photo_1_(4).JPG
Attachment 3: photo_2_(4).JPG
  8940   Tue Jul 30 16:21:46 2013 Alex ColeUpdateElectronicsPhotodetector Input Modulation

 [Eric, Alex]

We successfully used our system to modulate the input to a single photodetector. The RF Out of the network analyzer went to the Mod In of our laser, which was operating at 98 mA. The laser's output was sent to our 1x16 optical splitter. This provided input signals for both our reference detector and AS55. Our reference detector's output was sent to the network analyzer's R input, while the AS55's output was sent to the network analyzer's A input. 

We still need to work out the specifics of how the modulation works. Specifically, we want to look at the amplitude of the network analyzer's output. Additionally, we may have been saturating our reference detector, causing noise problems.

  8947   Wed Jul 31 17:02:17 2013 Alex ColeUpdateElectronicsPreliminary Photodetector Frequency Reponse Measurements

[Eric, Alex]

We used our setup from yesterday (elog #8940) to measure transimpedance measurements for AS55, REFL11, REFL33, and REFL55, using our Newport 1611 FC-AC as reference. We connected the fibers to their respective telescopes such that the beams focused on their photodetectors, using a multimeter to maximize photodetector DC output. Plots are attached. At first glance, the poles seem to be where they're supposed to be.

Note that the procedure used today is similar to what the eventual automated procedure will be. The main differences are (1) The RF Switch will be used rather than manual switching (2) NWAG4395A will be used to collect data rather than netgpibdata (3) Data will be fit using vectfit4.m and compared to some canonical set.

Attachment 1: REFL11.jpg
Attachment 2: REFL33.jpg
Attachment 3: REFL55.jpg
Attachment 4: AS55.jpg
  8955   Thu Aug 1 18:55:20 2013 Alex ColeUpdateElectronicsPreliminary Photodetector Frequency Reponse Measurements


[Eric, Alex]

We used our setup from yesterday (elog #8940) to measure transimpedance measurements for AS55, REFL11, REFL33, and REFL55, using our Newport 1611 FC-AC as reference. We connected the fibers to their respective telescopes such that the beams focused on their photodetectors, using a multimeter to maximize photodetector DC output. Plots are attached. At first glance, the poles seem to be where they're supposed to be.

Note that the procedure used today is similar to what the eventual automated procedure will be. The main differences are (1) The RF Switch will be used rather than manual switching (2) NWAG4395A will be used to collect data rather than netgpibdata (3) Data will be fit using vectfit4.m and compared to some canonical set.

 [Alex, Eric]

Today I spent some time mounting the launcher and performing the same data collection for POX11. I think I still need to focus the launcher so the photodetector gets a good signal, but the data from today wasn't too bad.  Additionally, I worked on matlab scripts to improve PDFR data analysis.

This time I collected data from the network analyzer using NWAG4395A in the netgpibdata directory. The advantage of this is that the computer tells the network analyzer to perform the sweep as well as retrieving the data.

For analysis, I improved my implementation of vectfit4.m so that it focuses in on the particular photodetector's predicted peaks and thus ignores much of the noise, giving a better fit. The raw data is the red circles in the 2nd attachment, while the fit is the blue line. I also had the program return the frequency value of the peak. For POX11, this was 1.106e+07 Hz.

I also finagled copies of existing programs to enable one to plot multiple transfer functions on the same axes. This function is /users/alex.cole/plottwo.m. I will eventually use this to compare new data to some canonical data so that we may monitor photodetector performance over time.

The eventual plan is to generate two plots per photodetector, one of which will compare new data to the canonical set, the other of which will show the fit of the data. Both will have subplots that zoom in around regions of interest (known peaks and notches), and the plot which displays the canonical set will also have Q's of peaks and their locations.

Attachment 1: POX11.jpg
Attachment 2: POX11fit.jpg
  8971   Tue Aug 6 12:43:23 2013 Alex ColeConfigurationElectronicsAS Table and Rack 1Y1 Additions

For the photodetector frequency response project, I finished the construction of our baluns chassis and mounted it in rack 1Y1 (1st picture).

After consulting with Jenne, I mounted the fiber launcher for REFL165 on the AS table such that it would not cause an obstruction. I aligned the launcher using a multimeter to monitor the DC output of REFL165, but looking at the data I got, it seems I need to do a better alignment/focusing job to get rid of a bunch of noise.

Attachment 1: photo_1_(5).JPG
Attachment 2: photo_2_(5).JPG
  8979   Wed Aug 7 15:51:53 2013 Alex ColeConfigurationElectronicsRF Switch Change

For the photodetector frequency response project, our new RF Switch Chassis (NI pxie-1071) arrived today. I took the switches out of the old chassis (Note for future generations: you have to yank pretty darn hard) and put them in the new chassis, which I mounted in rack 1Y1 as pictured. 

The point of this new chassis is that its controller is compatible with our control room computer setup. We will be able to switch the chassis using TCP/IP or telnet, aiding in our automation of the measurement of photodetector frequency response.

Attachment 1: photo_(2).JPG
  9004   Tue Aug 13 11:40:19 2013 Alex ColeSummaryElectronicsRFPD Demod Filter Frequency Response Measurement

 For the RF PD Frequency Response Measurement project, we get each PD signal from the "PD RF Mon" output of each demodulator board corresponding to our PD under test. Therefore we can't neglect the frequency response of various filters inside the demodulator board. I used our Agilent 4395 Network Analyzer to gather frequency response data for each demodulator board being considered for the RFPD frequency response project (AS55, REFL11, REFL33, REFL55, REFL165, POX11, POP22, POP110).

The NA swept over a frequency range of 1-500 MHz. Data was collected using NWAG4395A (from the netgpibdata directory). It should be noted that the command line options -a 16 -x 15 (averaging=16 and excitation amplitude=15 dBm[the max]), in addition to the usual command line options described in the help file, were used to minimize noise. 

The data is located in /users/alex.cole. The file names are in the format [PDNAME]DemodFilt_1000000.dat (e.g. REFL11DemodFilt_1000000.dat). Results for POP110 are shown below.

Attachment 1: photo_(3).JPG
Attachment 2: test.jpg
  9005   Tue Aug 13 11:54:40 2013 Alex ColeHowToElectronicsRF PD Fiber-Coupled Laser Operation

This post pertains to the fiber-coupled diode laser mounted in rack 1Y1.

To turn the laser on, first turn the power supply's key (red) to the clockwise. Then make sure that the laser is in "current" mode by checking that the LED next to "I" in the "Laser Mode" box in lit up. If the light is not on, press the button to the right of the "I" light until it is. Now press the output button (green). This is like removing the safety for the laser. Then turn the dial (blue) until you have your desired current. Presently, the current limit is set to around 92 mA.

To turn the laser off, dial the current back down to 0mA and turn the key (red) counterclockwise.

Attachment 1: photo_(4).pdf
  9006   Tue Aug 13 13:30:41 2013 Alex ColeConfigurationElectronicsCable Routing

 I routed cables (RG405 SMA-SMA) from several demodulator boards in rack 1Y2 to the RF Switch in rack 1Y1 using the overhead track. Our switch chassis contains two 8x1 switches. The COM of the "right" switch goes to channel 7 of the "left" switch to effectively form a 16x1 switch. The following is a table of correspondences between PD and RF Switch input.


PD Left/Right Switch Channel Number


POX11 L 0
AS55 R 1
REFL55 R 7
POP22 R 6
REFL165 R 5
REFL33 L 7


ThePOP110 demod board has not yet had a cable routed from it to the switch because I ran out of RG405.

We should also consider how important it is to include MCREFL in our setup. Doing so would require fabrication of a ~70 ft RG405 cable. 

Attachment 1: photo_(6).JPG
  9059   Fri Aug 23 21:01:38 2013 Alex ColeHowToElectronicsAutomated Photodetector Frequency Response System

 This post describes how to use the Automated Photodetector Frequency Response System.

On the mechanical side, turn on:

-the diode laser (in rack 1Y1)

-the RF Switch (in rack 1Y1)

-the reference PD (under the POY table)

-the AG4395A Network Analyzer

The NA’s RF output should go to the laser’s modulation input, the reference PD’s output should go to the NA’s R input, and the RF Switch Chassis’s output (which is the combination of the two switches’ COM channels using a splitter) should go to the NA’s A input.

Once this is done, navigate into /users/alex.cole and run PDFR.sh. This script collects data for each photodetector under consideration by switching using a python script and communicating with the NA via GPIB. It then sends all the data to RF.m, which fits the functions, plots the latest data against canonical data, and saves the plots to file.

The fitting function, fit.m, also outputs peak frequency to the command line. This function uses PD name data (e.g. ‘REFL33’) to choose an interval with minimal noise to fit.

The main script prompts the user to press enter after each NA sweep to make sure that measurements don’t get interrupted/put out of order by RF switching.

Once you're done, you should turn off the laser, NA, RF Switch, and reference PD.


Sometimes, the NA throws up and doesn’t feel like running a particular sweep. If this happens, it’s a good idea to keep the matlab script from trying to analyze this PD’s data. Do this by opening up RF.m and commenting out the calls to ‘fit’ and ‘canonical’ for that PD.

If fit.m complains about a particular set of data, it is often the case that the N/P ratio (where N is order of approximation and P is number of points in the interval) is too high. You can fix this by reducing N or making the PD’s frequency range (chosen in the fnew_idx line) larger.

Choosing a single PD

If you only want to grab the transfer function for one PD, first look up which switch input it belongs to. This information is contained in /users/alex.cole/switchList. To turn the switch to a particular input, type something like:

python rf.py “ch7”

This command uses TCP/IP to tell the switch to look at channel 7. Switch input numbers range from 1 to 16, though not all of them are in use.

Once the switch is looking at the correct input, you can run a sweep and download the data by typing /opt/rtcds/caltech/c1/scripts/general/netgpibdata/NWAG4395A -s 1000000 -e 500000000 -c 499000000 -f [filestem for output] -d [path of directory for output] -i -g 10 -x 15. 

  2075   Fri Oct 9 14:23:53 2009 Alex IvanovConfigurationDAQtpchn mystery

"Yes. This master file is used."


Does anyone know if this master file is the real thing that's in use now? Are we really using a file called tpchn_C1_new.par? If anyone sees Alex, please get to the bottom of this.

allegra:daq>more master


  4779   Thu Jun 2 10:19:37 2011 Alex IvanovSummaryDAQinstalled new daqd (frame builder) program on fb (target/fb/daqd)

I hope that new daqd code will fix the problem with non-aligned at 16 seconds frame file GPS times.

I have compiled new daqd program under /opt/rtcds/caltech/c1/core/release/build/mx and installed it under

target/fb/daqd, then restarted daqd process on "fb" computer. It was installed with the ownership of user root

and I did chmod +s on it (set UID on execution bit). This was done in order to turn on some code to renice daqd process

to the value of -20 on the startup. Currently it runs as the lowest nice value (high priority).


controls@fb /opt/rtcds/caltech/c1/target/fb $ ls -alt daqd
-rwsr-sr-x 1 root controls 6592694 Jun  2 10:00 daqd


Backup daqd is here:


controls@fb /opt/rtcds/caltech/c1/target/fb $ ls -alt daqd.02jun11
-rwxr-xr-x 1 controls controls 6768158 Feb 21 11:30 daqd.02jun11



  6094   Fri Dec 9 14:33:16 2011 Alex IvanovUpdateAdaptive FilteringC1OAF


I tried to figure out why red NO SYNC label became present in the C1OAF_GDS_TP screen after I added AA filters to the C1OAF model.

C1OAF model contains 8 libraries C1OAF_ADAPT for 8 DOF. I changed C1OAF_ADAPT library to C1OAF_ADAPT_AA library where I added 28 AA filters for 28 witness channels. It turns out that if I use this library for all 8 DOF then I see NO SYNC label, if only for one DOF (MCL) then I see green IOP label. This means that using AA filters for each DOF too much channels of filters are created for online system to operate. I think there is some number inside the code that one can not exceed. Analyzing compilation output after "make c1oaf" I figured out that without using AA filters we have 632 filters and using AA we have 856 filters.

For now I'll use AA filters for MCL only.

 I have a feeling we are not fitting into pre-allocated memory space in the shared memory between the front-end process and the epics process. Filter module data is overwriting some other data and that's why we are not getting a sync light. I suggest we upgrade to 2.4 code first and then we will figure out a way to expand memory areas to fit 856 filters.

  7146   Fri Aug 10 17:17:41 2012 Alex Masha DenUpdatePEMclassify seismic c code

Den and I installed a module in the c1pem model which has a feedforward neural network to classify seismic disturbance (10 means quiet, 20 truck, 30 earthquake). There is a channel SEIS_CLASS which should specify the class of the seismic signal. The code works for signals sampled at 256 Hz, so an anti-aliasing filter must be installed in order to decimate from the 2048 model.

The models were compiling slowly, so Alex removed the archiving feature (gzip and tar were taking a lot of time).

Den and I also had trouble with a simple for loop in our model, so we talked to Alex who noted that the -O3 compiler unravels for loops in a buggy way. Thus, we have compiled c1pem using the -O compiler.

PS: the Trilium seismometer now has legs.

  17513   Fri Mar 17 17:27:58 2023 Alex, TomohiroUpdateIMCArm Cavity Noise injection with WFS1/2 PIT and YAW

Tomohiro and I performed some tests under Rana's guidance to find cross corelations between WFS1 and WFS2 output signals in both pitch and yaw. We performed this test to further understand the degree to which our output matrices have been diagonolized.

Seen in attachment 1 is our base level with no injected noise source. In each figure, we also have inlcuded the coherence plot which compares each control signal to the overalll YARM power signal.

Attachments 2-5 display our results for injecting noise into each control signal individually.

We found the following corelations for each respective test:

Control Signal with Noise Corelated signals (order)
WFS1 PIT WFS1 YAW, WFS2PIT, WFS2 YAW (all equally corelated)
WFS1 YAW WFS1 PIT, WFS2 YAW, WFS2 PIT (most to least)
WFS2 PIT WFS1 PIT, WFS2 YAW, WFS1 YAW (most to least)
WFS2 YAW WFS2 PIT, WFS1 YAW (all equally corelated)

We judged our corelated signals by the peaks seen from out noise injection on the power spectrum as well as by their coherence at the same frequencies of our noise (20Hz-30Hz) compared to the overall power spectrum of YARM.


Performing this measurement was done using diaggui and awggui. The diaggui files for each test are saved at: "users/Templates/singleArmCal/ArmCavityNoise_230317_2_WFS1_PIT"

To properly fix each of the control signals to the same magnitude plotted for YARM output, we callibrated each plot using the settings seen in Attachment 7. First the units were changed on the plots to represent the true scale of each measurement:

We found that the ETMY actuation strength is 10.843e-9 / f^2 (from 17376) and used this to clibrate the plots to the nanometer scale. Next the gain was adjusted such that each plot would align over the YARM output when noise was injected onto it, setting a basis for all four measurements.

Finally, some filtering poles were added to the callibration for each plot such that it resembled that of the filters seen by the YARM ouput signal. (RXA: this is the 28 Hz ELP filter to simulate the dewhitening filters)

The measurements were taken with the settings seen in Attachment 8, and noise injected using the parameters seen in attachment 9.

RXA: Some edits/comments:

The noise was injected as band-limited random noise with a Normal distribution. We used noise rather than lines so as to capture the linear and bilinear noise contributions. In the case where the coupling is mostly bilinear, we would not expect to see much coherence.

The first attachment is a ASC noise budget for the single arm - in the high gain mode, the noise does not limit the noise as seen by the arm. Next is to see if its due to the MC dewhitening filters being on/off?

Attachment 1: ArmCavityNoise_230317_2.pdf
Attachment 2: ArmCavityNoise_230317_2_WFS1_PIT.pdf
Attachment 3: ArmCavityNoise_230317_2_WFS2_PIT.pdf
Attachment 4: ArmCavityNoise_230317_2_WFS1_YAW.pdf
Attachment 5: ArmCavityNoise_230317_2_WFS2_YAW.pdf
Attachment 6: Screenshot_2023-03-17_17-23-34.png
Attachment 7: Screenshot_2023-03-17_17-24-47.png
Attachment 8: Screenshot_2023-03-17_17-24-00.png
  5249   Tue Aug 16 16:59:20 2011 AnamariaUpdateRF SystemAM in the PM

Kiwamu, Keiko, Anamaria

Looking at the I and Q signals coming from REFL11 and REFL55 we saw large offsets, which would mean we have amplitude modulation, especially at 11MHz. We checked the PD themselves with RF spectrum analyzer, and at their frequencies we see stationary peaks (even if we look only at direct reflection from PRM). We changed the attenuation of the PSL EOM, and saw the peak go down. So first check is beam out of PSL EOM, to make sure the input beam is aligned to the crystal axis and is not giving AM modulation in adition to PM.

  5255   Wed Aug 17 15:47:18 2011 AnamariaUpdateSUSETMX Side Sensor slow channel down for a long time

Jenne, Anamaria

We aligned the ETMX OSEMs and ran into this issue. Looking at the SENSOR_SIDE channel, we pulled out the OSEM and determined that the open light voltage is 874 counts, so we centered it around 440 as well as we could. This is same channel as its slow counterpart SDSEN_OUTPUT (grey number immediately to the right on SUS medms).




The slow signal from the side sensor on ETMX was last seen in action sometime in May 2010!  And then the frame builder has no data for a while on this channel.  After that the channel shows some bistability starting Sept 2010 but has not been working.  The fast channel of this sensor  (C1:SUS-ETMX_SDSEN_OUTPUT) does work so the sensor is working.  Probably is a loose contact... needs to be fixed.



  5278   Mon Aug 22 20:37:43 2011 AnamariaConfigurationRF SystemPlan for install of 3f PDs

I made a quick sketch of how to include two more RF PDs on the REFL beam, given the space we have on the table. We want to install REFL33 and REFL165, 3f signals for the the two modulation frequencies we are using. The point is to make the distance from first beam splitter the same to all PDs so that we can use only one lens before this BS to make the beam the right size. Currently there are 2 PDs on the refl beam, REFL11 and REFL55, predictably. So the drawing shows 4 PDs. Drawing is to scale but is a bit coarse. Hopefully we'll take pictures once we're done.

Reference from current BS splitting beam to the existing PDs.

Attachment 1: 40m3fReflPdLayout.pdf
  5284   Tue Aug 23 06:49:24 2011 AnamariaUpdateGeneralmore in-vac work : AS clipping fixed and OSEM/oplev adjustment

Where was the AS clipping?! Ah, the suspense...


  + fixed the AS clipping issue


Quote from #5275

We need to check/fix the AS beam clipping and once it's done we will readjust the OSEM mid range and the oplevs.




  5389   Mon Sep 12 18:45:04 2011 AnamariaConfigurationLSCAP table current layout

Before we install the REFL 3f PDs I made a drawing of the current table layout, since there has been no update lately. Once I've incorporated the two extra PDs (now seen sitting bottom left), I will update the drawing and post in the wiki as well.

Attachment 1: 40mAPtable.pdf
  5401   Wed Sep 14 01:19:20 2011 AnamariaConfigurationLSC3f PD Install in Progress

I have reconfigured the refl beam path on the AP table to include REFL33 and REFL165. Would be done if we hadn't prepared P BSs instead of S, which required some serious digging to find two others. And if someone hadn't stolen our two 3m SMA cables that Keiko and I made on our previous visit and I had left with the 3f PDs. I don't expect them to reappear but if they do, it would be grand.

Note: Refl beam from ifo looks a bit high, ~1cm on the lens 20'' from output port. Not sure what that means about ifo alignment change, I've left it as is. When we know we have a good alignment, we should be able to easily realign the beam path if necessary. If it remains the same, we might want to change the lens height.


1) REFL11 and REFL55 are now hooked up and aligned in a low power beam. (I set the power as low as I could by eye to not risk burning the PDs during alignment)

2) The required BSs and REFL33 and REFL165 are in place, powered.

3) I have set them in a configuration such that the beam is the same distance from the main beam, to adjust beam size easily for all 4.

4) Camera has been moved from main beam to behind a steering mirror, ND filters removed, centered on camera.

To Do:

1) Find one more longish SMA cable.

2) Align beam on REFL33 and REFL165.

3) Check beam size carefully. (I get a plateau on the scope, and I can "hide" the beam on the PD, but it could be better. The path has become longer by ~5-8inches.)

4) Adjust power.

5) Redo layout diagram, post in wiki.

  5414   Thu Sep 15 02:18:19 2011 AnamariaUpdateLSCMICH locked and attempt to lock PRCL

Kiwamu, Keiko, Anamaria


We were able to lock PRC using REFL11I after improving the MICH dark fringe a bit (moving BS) and rotating AS55 and REFL11 such that the signal was maximized in the phases we were using. The dark port is not so dark... but the lock is stable.

I had finished the whole REFL path alignment, but I didn't have a good input beam reference at the time, which is why we had to realign the PDs and the camera. We only had strength to realign 11 and 55. Otherwise, we just need to tweak and center beam on 33 and 165, figure out what's up with 55 and be done with the AP table mods. I hope.



 Anamaria, Keiko

- We aligned MICH and were successfully locked MICH using AS55Q. The other mirrors were misaligned so that the other degrees of freedom didn't exist. AS55 was fed back to BS. The f2a filters on BS suspension were required to lock, because the pos feedback was unbalanced to angle degrees of freedom.

- We tried to lock PRCL next, however, because we aligned the MICH and the REFL beam paths were changed, REFL PDs didn't have the light anymore. The REFL paths were modified now, so we will try the PRCL locking next.

- We couldn't confirm REFL55 signals although we alined the REFL paths to REFL55 PD.


  5430   Fri Sep 16 03:22:11 2011 AnamariaUpdateLSCMore Refl PDs Work and Attempt at DRMI

Kiwamu, Keiko, Anamaria

I started today with a different input beam, so I had to realign the REFL path again. Then we measured the RF signal out of the 4 REFL PDs and found them to be too low. We increased the power to around 10mA for each diode, and we can see the right modulation frequency on each diode, though REFL165 is way too weak so we might need an RF amplifier on it. We will measure demod board noise tomorrow.

We had an issue with REFL165 not giving the right DC level, low by a factor of 10, even though it was receiving the same optical power as the others. We fifteen-checked clipping and alignment, then pulled it out and measured it on the test stand - found it to be ok. So I uplugged its power cable at the rack and connected it to the AS165 slot. Problem sloved. Not sure what was wrong with the other power slot.

Then we found REFL55 to be clipping on its black glass, we fixed that. But the REFL55 DC power still changes a lot with seemingly not huge motions of the PRM. We'll investigate more tomorrow.

We added a lens in the path to REFL165 because unlike the others it is a 1mm diode. All diodes have about half a turn to a full turn flatness of maximum (on tiny steering mirror).

We set the whitening gain on all four diodes to 21 db.

Not sure if we should set the power to be different on these diodes since their sensitivity is different to RF, and now REFL11 sees huge signal.

We continued the DRMI locking attempt and brought in the SRC, using AS55I to control it. It kind of works/stays locked. We did manage to get MICH and PRC better controlled than last night, but with SRC in the mix, something is wrong. We have to redo f2a filters on SRM and hopefully things will be better after Jenne's suspension work tomorrow. Oplevs not optimized yet either.

We intend to realign POY beam path so we can monitor power in cavities.

  5475   Tue Sep 20 03:12:14 2011 AnamariaUpdateSUSJenne's Scripts started

I followed Jenne's instructions, ran the matrix filler script and then set the optics to freeswing. Someone has to burt resture and damp them in the morning.

  5489   Tue Sep 20 20:58:35 2011 AnamariaConfigurationLSCNew AP Table Drawing

As promised, I have made a final AP table drawing, including the MC camera relocation changes by Kiwamu. I have posted it in the wiki on the tables list, and on the AP table page I've attached the inkscape .svg I used to make it, if someone needs to do small modifications.

Attached is a pdf version of it.

Big changes:

1) REFL beam has been split into 4, to go in equal powers and equal beam size to the now 4 REFL RFPDs, 11, 33, 55 and 165. A lens had to be added for REFL165 because it's a 1mm PD instead of 2mm like the other 3.

2) MC camera has moved.

3) I've cleaned up most of the random components on the table, put them away, and tidied up the cabling.


Attachment 1: APtableSep20th.pdf
  5513   Thu Sep 22 04:49:14 2011 AnamariaUpdateLSCLocking status update - Some Scripts, No Louck

The scripts I wrote can be found in /users/anamaria/scripts/sensemat/

]There are two of them:

- one that sets all the switches, gains, frequencies, etc, then cycles through the various RFPDs I and Q into the LOCKIN signal, so as to see the sensing matrix.

- the second one is a matlab script that takes the crappy file tdsavg outputs and makes it into a cute mag/phase matrix.

They're quite primitive at this point, I've forgotten a lot of tcsh... may improve later. But could be useful later to someone else at least.

I don't think it's particularly the fault of the script that we can't measure the sensing matrix. We can slam on the excitation by hand, and it holds for a little while. I set a wait time for lock to adjust, and most times it just oscillates a bit for a few seconds. Also, the script turns on the excitation and it's done, the rest is just measurement, then turns it off at the end. So during the script, there's not much to deal with, except keeping the lowpass filters quiet when switching the signal to demod; but that doesn't go anywhere, so it definitely doesn't disturb the ifo. Turns out pressing the RSET clear history button needs a 2 to make it happen.

I think I might prefer to set the excitation to run, and then do the old retrieve-data-later-nds-matlab thing. I do not trust these measurements without coherence and a bit of variance study, given instabilities.

Point is... Even on carrier, the PRC lock is not stable by any means. Can barely turn on low freq boosts, every other lock. Until we fix the lock stability issue, there's not much to measure I guess.

Unfortunately, I don't know how to make that happen. Before we leave on Friday we could do a few sanity checks such as measuring the noise of the RFPDs vs ADC+whitening, which I may have said I would do; and perhaps setting up a couple OSAs, one on REFL, one on AS, to make sure we know what the sidebands are doing. Both of which Rana suggested at some point.

(There used to be a quote here from Keiko here but I got mad when it reformated my entire log to be one cluster- hence the look)

  5525   Thu Sep 22 22:55:01 2011 AnamariaUpdateLSCPOX channel = POY PD connected + Bad Rack

Keiko, Anamaria

We decided we needed a DC channel to sense the gain in the PRC, so we set to align POY55. It took a while because the beam was very weak, and it comes in upwards, so we used a couple of mirrors to bring to a reasonable flat level, and put it on the PD. Then we went to read the DC out and we got 1.3V stationary! Nonsense. We also realized there is no LO for this PD, or any other 55MHz PD, aside from REFL55. Oh well, we only wanted the DC for now. POY55 is aligned (decently).

Koji told me to try swapping the power cable, so I unplugged it at the rack and plugged it in another power card. And it worked! I then moved the DC out (back of rack) to follow the front, and it turns out POY55 diode is read on the POXDC channel. I plugged and unplugged it in disbelief, but it is what it is. At least we have a readout on the power level in PRC.

I attach a picture of the power cards for the LSC RFPDs, with the 3 I found to be bad, and showing current config. I had to move REFL11 and POY55 from their assigned spot.

The two on the lower left are bad in the sense that they put an offset on the PD and make the DC readout be 1.3V for no reason (when working, for example, POY55 read 60mV). The one on the lower right I had trouble with some time ago, it made the PD not read any voltage at all (when working it would read at least 100mV). Beyond that I have not investigated what is up, since I could find working plugins.

Attachment 1: RFPDpowerRack2.pdf
  5545   Mon Sep 26 15:15:45 2011 AnamariaUpdateLSCRealignment of REFL / Some 3f PRMI locking / Recycling Gain

A few comments on REFL table alignment and REFL165.

Last time we realigned the table was after the PZT work by Koji/Kiwamu; we made sure that the beam was going through optics satisfactorily and that we were reading reasonable numbers. I did use primarily a viewer to align onto PD, after which we used the voltage reading to center better around that spot. As desired, I could not see the beam once it was centered on the PD. I never touched the PBS unfortunately, so I never noticed it was not fixed. Sad.

I am very surprised to hear the reading from REFL165, since I was reading around 400mV from it a few days before. Something strange happened in the mean time. I hope not when I was plugging and unplugging at the power rack for the POY work. But I would not have needed to touch REFL165. Those cables should get some strain relief at the rack, by the way.

I thought about it, and I must admit that after we centered camera on REFL (paired with an alignment), we did not check the beam path later, even after we saw that the REFL beam had moved. We only did a quick by-viewer check that the beams were not off of the PDs.


[Koji Suresh]

- The REFL path has been thoroughly aligned
Many optics had the spots not on the middle of the optic, including the PBS whose post was not fixed on the post holder.
We aligned the optical paths, the RF PDs, and the CCD. The alignment of the PD required the use of the IR viewer.
One should not trust the DC output as a reference of the PD alignment as it is not enough sensitive to the clipping.

We aligned the optical paths again after the reasonable alignment of PRM is established with the interferometer.
"Next time when you see REFL spot is not at the center of the camera, think what is moved!"

- The REFL165 PD is disconnected from the power supply
I found that the REFL165 PD is producing 7.5V output at the DC monitor no matter how the beam is blocked.
As I could not recover this issue by swapping the power connector at the LSC rack, I disconnected the cable
at the RFL165 PD side. I need to go through the PD power supply circuit next week.


  5243   Mon Aug 15 21:43:29 2011 Anamaria and KeikoSummaryLockingcentral part ifo locking project

 REFL33 and REFL165 cables were connected from the AP table to the rack.  Cables on the rack for REFL33I, 33Q, 165I, 165Q ports were connected, too. Connections were confirmed by the data viewer. Two SMA cables which will be used for the two PDs on the AP tabl were built. We will be able to place the two PDs tomorrow. The beamsplitters to split the laser to REFL33 and REFL165 ports were mounted and ready to be placed.

  15762   Wed Jan 13 16:09:29 2021 AnchalHowToCDSAcromag wiring investigation

I'm working on a better wiring diagram that takes into account multiple power supplies, how their GND is passed forward to the circuits or sensors using those power supplies and what possible wiring configurations on Acromag would give low noise. I think I have two configurations in mind which I will test and update here with data and better diagrams.

I took some striptool images earlier yesterday. So I'm dumping them here for further comments or inferences.

Attachment 1: SimpleTestsStriptoolImages.pdf
SimpleTestsStriptoolImages.pdf SimpleTestsStriptoolImages.pdf SimpleTestsStriptoolImages.pdf SimpleTestsStriptoolImages.pdf SimpleTestsStriptoolImages.pdf SimpleTestsStriptoolImages.pdf SimpleTestsStriptoolImages.pdf
  15774   Wed Jan 20 18:07:09 2021 AnchalSummaryBHDHAM-A Coil Driver measurements before modifications

I have taken transfer functions and noise measurements of the two HAM-A coil driver boxes D1100687 #S2100027 and #S2100028. All transfer functions look as expected. I'm not sure about the noise measurements. If anyone sees flaw in my measurement method, please let me know. I'm not sure why in some channels I got 10Hz harmoni peaks in the noise. That was very strange. Also let me know if my current noise estimate is wrong.

Transfer Function Measurement details

  • SR785 source out was connected to the differential amplifier input of D1900068.
  • The one pair of two BNC outputs of this differential amplifier goes directly to the SR785 Input 1 A and B.
  • The DB9 output of the differential amplifier goes to the Coil Input DB9 connector J3.
  • Header W2 was shorted to provide ground to the incoming signal.
  • Header P4 was shorted to enable all the channels manually.
  • Normal operation is the Acquisition mode (Acq) while when pins of header P3 are shorted, we go into the Run mode for respective channel.
  • The “To Satellite Box” DB25 port at the read side was conencted to a DB25 breakout circuit and pins 1-9, 3-11, 5-13 and 7-15 were connected to 36 Ohm resistor to simulate Coil load.
  • The “Output Monitor” on the rear side is then connected to the test switch DB9 port on D1900068.
  • The the pair of BNCs from the test switch is connected to SR785 Input 2 A and B.
  • Measurements are taken with file D1100687_TF.yml and D1100687_TF_LF.yml.
  • A measurement of just cables without the DUT is taken as well.
  • Commands.txt list all the commands used.
  • All data is compiled and plotted in Plotting.ipynb
  • D1100117_S2100027_TF.pdf and D1100117_S2100028_TF.pdf shows all the transfer functions measured.

Spectrum Measurements

  • All channels were kept in disabled mode (Not shorting P4) to ensure their inputs are grounded on the board.
  • I ran two BNC cables with their centers connected to output monitors V2+ and V2- and one of their shields connected to board GND.
  • in SR785, A-B differential mode always runs with grounded shields mode, so effectively the board GND got grounded to SR785 GND through internal 50 Ohm resistor. But all ground loops have been evaded.
  • The two BNC cables were twisted together to minimize the area between the two center cores of the cables as that is the remaining pickoff possible in this measurement.
  • Instrument noise with cables was measured first but shorting the clips of the center cores and one of the shields of the two BNC cables together.
  • Measurements were taken with file D1100687_SP.yml and D1100687_SP_LF.yml.
  • D1100117_S2100027_Voltage_Noise_Spectrum.pdf and D1100117_S2100028_Voltage_Noise_Spectrum.pdf shows the measured voltage noise spectrum at the output monitors when loaded with 36 Ohms.
  • D1100117_S2100027_Current_Noise_Spectrum.pdf and D1100117_S2100028_Current_Noise_Spectrum.pdf shows the esitmate current noise through the coil calculated by dividing the measured voltage noise by 2436 Ohms.
Attachment 1: MeasurementData.zip
Attachment 2: D1100117_S2100027_TF.pdf
D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf D1100117_S2100027_TF.pdf
Attachment 3: D1100117_S2100028_TF.pdf
D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf D1100117_S2100028_TF.pdf
Attachment 4: D1100117_S2100027_Voltage_Noise_Spectrum.pdf
D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf D1100117_S2100027_Voltage_Noise_Spectrum.pdf
Attachment 5: D1100117_S2100028_Voltage_Noise_Spectrum.pdf
D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf D1100117_S2100028_Voltage_Noise_Spectrum.pdf
Attachment 6: D1100117_S2100027_Current_Noise_Spectrum.pdf
D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf D1100117_S2100027_Current_Noise_Spectrum.pdf
Attachment 7: D1100117_S2100028_Current_Noise_Spectrum.pdf
D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf D1100117_S2100028_Current_Noise_Spectrum.pdf
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