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  Coating Ring-down Measurement Lab elog, Page 18 of 18  Not logged in ELOG logo
New entries since:Wed Dec 31 16:00:00 1969
ID Date Authorup Type Category Subject
  400   Wed Aug 9 15:57:28 2017 ZachElectronicsModelingTriangular Geometry


  • I compared the triangular geometry to the original geometry and the excitation was only improved in 7 of the of 20 modes. In four of those modes the improvement factors ranged from almost 2 to over 3 while the other modes where only improved by about 25%. The other 13 modes were diminished drastically, 9 of them where less than half as excited. Given more time it may have been interesting to try and optimize the geometry of a triangular drive, but that would easily take the better part of a week. 

  402   Thu Aug 10 10:47:54 2017 ZachElectronicsModelingGeometry Ratios


  • The attached plots compare the new and old geometries with .5 mm and 1 mm sample gaps. They are the same plot on linear and logarithmic axes respectively



Attachment 1: Optimization_plot_lin.pdf
Attachment 2: Optimization_plot_log.pdf
  407   Tue Aug 15 00:09:01 2017 ZachElectronicsModelingESD Improvements


  • I did my best to increase the excitation in the higher order modes. By making the ESD narrower (a 6mm electrode overlap) the higher order excitation is improved drastically, by factors of between 10 and 30 for most modes.  I also created a double ESD (see image) that excited the modes by a factor of 3 or more better than the thinner drive. The plotted ratios are relative to the original geometry, but both of these geometries do better than previous geometries by factors of 2 or 3. 
  • After a lot of experimentation, I think that there are non-trivial numerical artifacts from the force projection method. I have noticed that in the modes that are almost entirely unchanged by modifications, both the mode and its doublet have equal regions of positive and negative antinodes directly above the ESD force profile. This can be more clearly seen in the attached mode plot, the rectangle represents the region of the ESD. As a result of this, when the mode shape and force profile are multiplied and integrated the resultant force is very small. I expect this does not appear in the lab because the modes could be rotated at a different angle relative to the ESD. I am not sure how to effectively resolve this, perhaps checking other rotations of the mode shapes could be productive though I am unsure how to effectively accomplish this. 

Attachment 1: double.pdf
Attachment 2: double.jpg
Attachment 3: offset10.jpg
Attachment 5: offset10.jpg
Attachment 6: double.jpg
Attachment 9: thin.png
  411   Wed Aug 16 10:04:24 2017 ZachElectronicsModelingESD along edge


  • I placed created a very narrow ESD placed along the edge of the sample. The thought behind this is that it will not cross over into any other modes that will cancel out the force. However, it does not appear to couple force into enough of the area of the disk to cause a worthwhile improvement, as can be seen in the plot, more modes lost amplitude than gained and some were worse by as much as a factor of 1000.

Attachment 2: overlay15.jpg
  412   Wed Aug 16 11:36:13 2017 ZachElectronicsModelingMiddle ESD


  • I created a model with a drive offset in the middle. It improved one of the modes by a factor of 14 or so, but overall, it diminished the vast majority of the modes by as much as a factor of 100. 

Attachment 2: overlay23.jpg
  414   Wed Aug 16 16:05:09 2017 ZachElectronicsModelingTwo ESD First test


  • I created a model with two ESD's, essentially a combination of my previous two attempts with one ESD on the edge and one closer to the center of the disk. This test was quite successful compared to previous trials, the improvement seems to be on an average of a factor of 10. No modes are weakened by this design. I am going to run a sweep adjusting the central ESD and see what placement is best.
  • Attached is an overlay of the force profile and all of the modes. Note that this image is very large, and is useful as a digital reference or very large print only.

  415   Thu Aug 17 14:19:04 2017 ZachElectronicsModelingTwo ESD Optimization


  • I ran a sweep of the position of the middle ESD to determine the optimal arrangement. From the original geometry I offset the central ESD between -2 mm and 11 mm. From the plots below I conclude that the optimal geometry is the one that is shifted 2 mm to the right of the original design. 
  • The first plot is the sweep data as a ratio to the data of the current geometry for all modes. The second plot is the root mean square of the eight high frequency modes that change the most over the course of the sweep, those are modes 9, 11, 13, 14, and 17-20. The frequencies of those modes in order are 9.5kHz, 11 kHz, 14 kHz, 16 kHz, 19 kHz, 20 kHz, 21 kHz, and 23 kHz. There is a very apparent peak at 2 mm which is the driving force behind my conclusion that it is the optimal design. The next two plots are the 2mm shifted design and the original design as ratios to the original geometry. The 2mm shifted geometry is much more consistent than the original design, there is a very noticeable minimum in the original design (improvement by a factor of 2) for the 23 kHz mode that is resolved in the shifted design to a factor of 9.
  • The final plot are ratios of the two designs relative to each other. I found this plot useful to convince myself that the 2 mm shifted design was better than the original, particularly in the region above 1.5 kHz.

Attachment 1: Two.jpg
Attachment 2: Two.jpg
Attachment 3: RMS.jpg
Attachment 4: 2mm_shifted.jpg
Attachment 5: Sweep_Ratio.jpg
Attachment 6: Dynamic_Modes.jpg
Attachment 7: Sweep_Ratio.jpg
Attachment 8: Comparing.jpg
Attachment 9: 0mm_shifted.jpg
Attachment 10: Comparing.jpg
Attachment 11: 0mm_shifted.jpg
Attachment 13: 2.Dynamic_Modes.jpg
  416   Thu Aug 17 23:34:51 2017 ZachElectronicsModelingOptimized ESD Drawing


  • I made a drawing of the Optimal ESD design. The bottom combs (right hand in the rotated image) are set to ground and the 5 arm comb is set to a positive voltage and the 2 arm comb is set to a negative voltage. 

Attachment 1: OptimizedESD.pdf
  417   Fri Aug 18 10:50:53 2017 ZachElectronicsModelingESD's with positive voltage


  • With both electrodes driven at a positive voltage, the results are still an improvement over the original design, but by smaller factors, particularly in 3 of the higher frequency modes at around 2 and 3 kHz. With another parametric sweep I may be able to find a better design. The opposite voltage was useful because it could couple force in opposite directions to adjacent anti-nodes with opposing signs. An adjusted configuration could probably be found to interact with anti nodes with the same signs. An alternative option would be to leave the radial position of the more central ESD constant but rotate it relative to the sample by some amount, though this would also require an additional parametric sweep as well as a much larger ESD. 

  419   Fri Aug 18 14:15:47 2017 ZachElectronicsModelingSame Voltage ESD Sweep


  • I ran a sweep of the central position in the two ESD setup with both set at the same voltage. There were two designs that maximized excitation by different metrics, the design with a 3 mm shift from the original design maximized excitation overall, but the 20 kHz mode was worse by a bout a factor of 5. The design with a -2 mm shift maximized the high frequency modes, particularly the modes most affected by the shift.
  • MATLAB crashed shortly after the sweep so I will have to recreate the RMS plots of the dynamic modes later.


Attachment 1: two_positive_ratio_sweep.pdf
Attachment 2: -2mm_two_positive.jpg
  420   Fri Aug 18 15:10:23 2017 Zach, GabrieleElectronicsModelingESD prototype


  • We created a prototype of PCB for the ESD design. Unfortunately the orientation of the two combs was flipped, so it will require some creative mounting to get right. The final design had a 6 mm offset between the two combs, .5 mm traces and 1 mm gaps between them The vertical traces are 12 mm long and there is a 3.75 mm gap between the end of the vertical traces and the opposite horizontal one. The ESD will arrive on Tuesday to be installed Wednesday and we will see how the new design works out.


Attachment 1: Crime_ESD_Zach_prototype.pdf
  421   Wed Aug 23 14:11:13 2017 Zach, GabrieleElectronicsMeasurementsInstalling ESD Prototype


  • Installed ESD Prototype design by taping it to the older design, we then lowered the mount until it was as close as we could reasonably get it. The new PCB lines up when the top of the new PCB is lined up with the last electrode on the old one. The new PCB was slightly too narrow, the mounting holes are very close to the edge of the PCB, this can easily be corrected in later models.
  • Installed sample S1600541 into the single sample apparatus
  • Roughing pump on at 12:32
  • Turbo pump on at 2:28pm

Link to image1.JPG Link to image2.JPG

Attachment 1: image1.JPG
Attachment 2: image2.JPG
  401   Wed Aug 9 17:07:57 2017 ZacharyElectronicsModelingOptimization Summary


  • From the data I have gathered from a variety of MATLAB sweeps, I think that the optimal geometry I can produce has the parameters in the attached image. Neither the original or optimized drawing is to scale. The gap between the arms of the electrodes should be 1.25 mm, the arm width 0.55 mm, the arm length 16 mm, and the offset of the arms 3.5 mm.

  • It is also optimal to place the ESD as close to the sample disk as can reasonably be achieved, at around 0.5 mm away. Since the force on the disk scales exponentially with the distance from the ESD, decreasing that gap is the most substantial way to impact the excitation. Decreasing the gap from 1 mm to .5 mm increases the excitation of the modes by approximately a factor of 8.

  • From my simulations, the shift in geometry alone still has a useful impact on the excitation. Modes 1 and 3 are the only two modes that are less excited by the new geometry, mode 1 is 10% weaker  and mode 5 is 5% weaker. Modes 5 and 6 are nearly unaffected by the shift, mode 5 is 2% stronger and mode 6 is 5% stronger.  Modes 7, 18 and 19 are outliers, 7 is excited by a factor of 7, 18 by a factor of 4 and 19 by a factor of 17. The rest of the modes are improved by between a factor of 1.5 and 3. For mode numbers, shapes, and frequencies a plot is included.

Attachment 1: resonantmodes.pdf
  689   Mon May 13 18:37:47 2019 aaronCleanGeneralClean room gear

Mon May 13 18:37:37 2019

Entered CRIME lab to borrow 4x hair nets and face masks. Can you please advise on what I should order for clean lab equipment? There are more options on techmart than I anticipated. We're in the process of increasing the cleanliness of the SiQ experiment.

  696   Mon May 20 10:35:45 2019 aaronCleanGeneralClean room gear


There is a buy list of approved clean room supplies posted here https://dcc.ligo.org/LIGO-E1300399. This list is used by designated people to keep clean rooms supplies stock at each site including LIGO labs in Downs, 40m and the CRIME lab. Not sure what lab you are working in and what regulations you have there. Typically we study the list of the approved supplies, figure out what budget can be used for supplies for a particular experiment. Depending on what your project is, you may be able to just take what you need from the existing LIGO stock (I believe there is one for Downs and one for Bridge and 40m) or work with Liz, Bob or Chub on ordering it for your via approved channels.


Mon May 13 18:37:37 2019

Entered CRIME lab to borrow 4x hair nets and face masks. Can you please advise on what I should order for clean lab equipment? There are more options on techmart than I anticipated. We're in the process of increasing the cleanliness of the SiQ experiment.


  702   Fri May 24 15:08:19 2019 alenaGeneralMeasurementsS1600713 S1600714 S1600715 S1600716


  • 15:00 in chamber
    • S1600713 in CR1
    • S1600714 in CR2
    • S1600715in CR3
    • S1600716 in CR4
  • 15:08 roughing pump on
  • 15:22 turbo pump on

Low pressure gauge glitching again. Tried restarting the gauge a few times - no result. Vented the chamber.

15:50 restarted the rouging pump, then the tubbo - no result. Aborted the measurement


  40   Thu Jul 14 15:30:48 2016 ericqElectronicsConfigurationCymac RTS configuration

We played around a bit with the cymac, in efforts to make things better.

  • We disabled some more fancy-sounding options in the machine's BIOS
  • I created safe.snap files for the x3iop and x3tst models 
    • x3iop's was created by booting the model while mashing the EPICS command to set the burt restore bit, and then saving the EPICS database to file via the SDF screen
    • x3tst's was created by copying an existing .snap file 
  • I gave the controls user ownership of /frames via sudo chown controls:controls /frames
  • I then created the following folders (which the daqd log was complaining about not finding_
    • /frames/full
    • /frames/trend/minute
    • /frames/trend/minute_raw
    • /frames/trend/second
  • I also created the folder /opt/rtcds/tst/x3/target/fb, since that is listed in the daqd config as the nds job dir. (However nds does not seem to be running. Is it needed? I couldn't compile it in the rtbuild directory)

As I see it, the main problems that persist are:

  • daqd crashes over and over again every few seconds
    • The logs seem to be complaining about EPICS server problems. Is the related to whatever situation made the epics-env script neccessary?
  • The IOP seems to be taking too much time: 8-9 usec
    • This is especially problematic as Gabriele actually wants to run the IOP at an even faster rate than the current 64k, which isn't possible with the current timing
  173   Thu Nov 10 14:13:34 2016 gabrieleElectronicsConfigurationMATLAB code to control Thorlabs stages

To be used to automate the laser polishing.

Attachment 1: move_complete.m
function move_complete(varargin)
    global moving;
    moving = false;
Attachment 2: throlabs_activex.m
%% init the controllers
f1 = figure();
f2 = figure();
tstage = actxcontrol('MGMOTOR.MGMotorCtrl.1', [20 20 600 400], f1);
rstage = actxcontrol('MGMOTOR.MGMotorCtrl.1', [20 20 600 400], f2);
set(tstage, 'HWSerialNum', 27001029);
set(rstage, 'HWSerialNum', 27501183);

... 119 more lines ...
Attachment 3: animation.m
% try a sequence of movements


% laser position
a0 = acos(36/(75/2));  
laser = [-75/2*sin(a0), 75/2*cos(a0)];

% initial position
t = 0;
... 59 more lines ...
Attachment 4: draw_wafer.m
function draw_wafer(translation, angle, laser)
    d = 75; % diameter
    f = 36; % distance of flat from center
    a = acos(f/(d/2));  % half angle opening of the flat
    % build wafer in reference position and orientation
    phi = [linspace(a, pi-a, 100), linspace(pi+a, 2*pi-a, 100)];
    coordinates = [-d/2*cos(phi); d/2*sin(phi)]';
    coordinates(end+1,:) = coordinates(1,:);
... 25 more lines ...
  1   Wed Jul 11 23:01:01 2012 janoschOpticsCharacterizationstarting the multi-color scatter experiment

Steve Maloney, a visiting highschool teacher, and I have started to set up a new scattering experiment in the Richter lab. The idea is to take images of large-angle scattered light using different lasers. We have one 633nm laser, and 532nm and 405nm laser pointers. The goal is to uniformly illuminate the same disk of about 1cm diameter on a silver-coated mirror with all three colors. We use a silver-coated mirror to make sure that the light is reflected from the same layer so that all colors are scattered from the same abberations.


The image shows one of the laser pointers and the HeNe laser. The first step is to widen the beam with a f=5cm broadband, AR coated lens (Newport PAC15AR.15). The diverging beam is then aligned through an iris to give it the right size on the mirror. In this way, illumination is almost uniform on the mirror surface.


The mirror is mounted over the rotation axis of a unipolar stepper motor. For the moment we only took images from fixed direction (initially with a commercial digital camera, later with a monochromatic Sony XT-ST50 CCD camera. The problem with the commercial camera was that you cannot completely control what the camera is doing. Also it would have been very difficult to calibrate the image once you start comparing scattering with different colors. A f=7.5cm lens is used to image the illuminated disk on the CCD chip to make maximal use of its resolution. The CCD signal is read out on a Windows machine with an EasyCap video capture device connected to a USB port. Standard software can then be used to take images or record videos. For some reason the capture device reduces the image size to 640x480 pixels (a little less than the size of the CCD chip).

Eventually the camera and lens will be mounted on a metal arm whose orientation is controlled by the stepper motor. The stepper motor was part of the Silicon Motor Reference Design (Silicon Laboratories). It comes with all kinds of cables and a motor control board. Software is provided to upload compiled C code to the board, but for our purposes it is easiest to use primitive communication methods between the PC and the board. We are working with HyperTerminal that used to be part of Windows installations, but now it has to be downloaded from the web. This program can send simple commands through TCP/IP and COM ports. These commands allow us to position the motor and define its rotation speed. Since our PC does not have a serial port, we purchased a Belkin USB Serial Adapter. You will have to search the web to find suitable drivers for Windows 7 x64. Luckily, Magic Control Technology has similar products and the driver for their U232-P9 USB/serial adapter also works for the Belkin product.

So our goal for the remaining weeks is to take many images from various angles and to set up the experiment in a way that we can VNC into our lab PC and control everything from the Red Door Cafe.



  2   Fri Jul 13 10:34:35 2012 janoschOpticsCharacterizationcamera image

We were confused a bit about how the camera image changes when you move the arm that holds the camera and lens around the mirror. It seems that scattering centers move in ways that cannot be explained by a misaligned rotation axis. So we wanted to make sure that the mirror surface is actually imaged as we intended to. We generated a white grid with 0.7cm spacing and black background on a monitor. The image that we saw is exactly how we expected it to be. So the image mystery has other reasons.

  3   Fri Jul 13 20:53:35 2012 janoschOpticsCharacterizationtwo images

The following two pictures were taken from the same angle with green (left) and red (right) incident laser at an angle of 15deg from the incident beam (reflected to about -5deg). Some scattering centers are collocated. The green laser power is about 5 times as high as the red laser power, but this factor does not seem to calibrate the image well (the green image becomes too dark dividing all pixel values by 5). So there seems to be a significant difference in the divergence of the two lasers. We will have to use a photodiode to get the calibration factor. These images were taken after cleaning the mirror. Before cleaning, there was way too much scattering and the images were mostly saturated.


  4   Tue Jul 17 18:32:11 2012 janoschOpticsCharacterizationpurple images

We have the new 405nm laser pointer.  The image to the left shows the scattered light from the red laser, the image to the right scattered light from the purple laser. Both images were taken 30deg with respect to the normal of the mirror surface. Also, we got a new gallon of Methanol. After cleaning the mirror multiple times, the scattered light became significantly weaker. So the purple images look very different from red and green. It could be that the lens that we use to image the mirror surface is the problem since it is specified for the wavelength range 1000nm-1550nm. Could it also be the CCD camera? Anyway, to be sure I will order another broadband lens.



  5   Wed Jul 18 18:43:34 2012 janoschOpticsCharacterizationgone with the wind

Here a little purple video. It starts with scattering angle around 15deg and stops at about 80deg.
There are some clear point defects visible especially at small angles.
I will not start to think about some other interesting details of this video before I got the new lens.

Ed: The AVI did not run on Mac. I posted it on youtube. Koji

Attachment 1: Purple.avi
  6   Fri Jul 20 18:35:42 2012 janoschOpticsCharacterizationpurple improvements and first uncalibrated BSDF curves

Today we improved alignment of the lens-camera arm. We discovered earlier that this alignment affects the amount of "snowfall" on the scattering images. Looking at the latest 405nm video (see attachment), one can still see snowfall, but it is considerably weaker now and the true scatter image is clearly visible. We took a set of scatter images at certain scattering angles and produced BSDF curves. The shape of these curves has partially to do with the snowfall contribution, but one also has to keep in mind that the mirror quality is much worse than what has been used in the Fullerton measurement. We still need to calibrate these curves. The calibration factor is different for the two images so that you cannot even compare them at the moment except for their shape.


Today we also got the new broadband lens for the camera arm. First measurements show that image quality is better. Playing a bit around with distances between object mirror, lens and image plane, we also found that image quality becomes better when the lens and camera get closer to the mirror (which is only an issue for the 405nm measurement since 633nm and 532nm look very good anyway). So we are thinking to change the camera arm setup to make it much shorter.

Attachment 1: Purple.mp4
Attachment 2: Red.mp4
  7   Tue Jul 24 10:59:59 2012 janoschOpticsCharacterizationsum of purple and red

We played around with Matlab today. The first step was to convert light wavelengths into RGB colors. In this way we can combine images taken at different colors. The picture shows the purple and red images (stored in gray scale) in heat colormap. Then the sum of these two images is calculated in their natural RGB colors.



  8   Fri Oct 12 16:23:20 2012 janoschOpticsDaily Progressreassembled setup

Nothing has happened since Steve, the visiting highschool teacher, has left. Meanwhile, some parts of the multi-color BRDF setup were delivered. I assembled everything today and realigned the lasers. Everything is ready now for a three-color BRDF measurement (the previous Richter record was 2 colors). I will claim back my video capture device as soon as possible from my neighbors and then take new images.

  12   Sun May 8 13:35:04 2016 ranaElectronicsDesignDesign of optical lever electronics

Koji, Rich, and I recently came up with a new QPD design which is better for general lab use than the aLIGO ones (which have a high-noise preamp copied from iLIGO). 


This page has the mechanical drawing only, but perhaps Rich can tell us if he's ready to make the first version for you or not. I think you can get by with the old design, but this new one should be lower noise for low light levels.

  131   Wed Sep 28 10:26:58 2016 ranaGeneralGeneralreferences on ideal glasses

Some easy to read reviews on thin films and ideal glass for people getting started in this Q measuring game.

  1. M. D. Ediger, in PNAS  (2014), pp. 11232–11233.

  2. A. J. Leggett and D. C. Vural, arXiv cond-mat.dis-nn, arXiv:1310.3387 (2013).

  3. L. Berthier and M. D. Ediger, arXiv cond-mat.mtrl-sci, 40 (2015). Phys. Today.

  4. G. Parisi and F. Sciortino, Nature Materials 12, 94 (2013).

  5. S. Singh, M. D. Ediger, and J. J. de Pablo, Nature Materials 12, 139 (2013).

  244   Sat Dec 17 06:29:15 2016 ranaElectronicsConfigurationTiming issue: is it a DAC issue?

I find sometimes that the probe configuration can give these distorted signals. For the Tektronix probes, its best to use a 500 MHz probe instead of the BNC clip leads. The probe also should be compensated by attaching to the gold fingers square wave generator on the scope front and adjusting the capacitor in the probe with a little screwdriver until the square wave becomes perfect.

  137   Wed Oct 19 16:40:24 2016 sults:GeneralMeasurementsS1600349

S1600439, not annealed, as received from Mark Optics


  • installed and balanced, pump down started at 4:38pm (roughing pump), turbo started at 4:51pm
  • removed from the chamber on 10/20 at about 11:00am



  • QPD centered at 9:25pm, excited (2000 V, 10 s) at 9:27pm, measurement ongoing.

The spectrum was noise than usual due to the roughing pump. I already found out in the past that I can reduce the noise by tweaking the position of the pump. This time however I wasn't successful.

Here are the results:

% Freq        Q                 Qlow (C.I. 95%)   Qhi (C.I. 95%)
1111.5        6.0958e+06        6.0641e+06        6.1279e+06
2549.6        3.6416e+06        3.6305e+06        3.6528e+06
4441.7        2.6916e+06        2.6879e+06        2.6953e+06
4512.9        2.1090e+05        2.0993e+05        2.1188e+05
6777.5        1.1797e+06        1.1790e+06        1.1803e+06
6790.9        3.8621e+06        3.8540e+06        3.8701e+06
6858.4        1.2434e+06        1.2295e+06        1.2577e+06
9548.0        1.2177e+05        1.1878e+05        1.2491e+05
10234.6       3.9934e+05        3.9351e+05        4.0535e+05
10399.0       2.8135e+05        2.7455e+05        2.8849e+05
12744.2       1.3145e+06        1.3115e+06        1.3174e+06
14211.3       3.8414e+06        3.8136e+06        3.8696e+06
16123.3       2.0276e+06        2.0181e+06        2.0372e+06
16135.8       5.2811e+06        5.2770e+06        5.2852e+06
16370.0       1.4976e+06        1.4922e+06        1.5031e+06
18689.3       4.2954e+06        4.2738e+06        4.3172e+06
23632.0       2.2796e+06        2.2528e+06        2.3070e+06
24797.4       8.7545e+05        8.5819e+05        8.9341e+05
27214.5       1.2566e+06        1.2374e+06        1.2764e+06
28947.5       1.7367e+06        1.7130e+06        1.7611e+06
29144.0       3.2148e+06        3.1213e+06        3.3142e+06



  • Roughing pump was creating too much noise, switched it off at 8:30am
  • Excitation at 8:35am (2000 V, 30 s)

Here are the results:

And the measured Q values:

% Freq        Q                 Qlow (C.I. 95%)   Qhi (C.I. 95%)
1111.4        6.2206e+06        6.2061e+06        6.2351e+06
2549.6        4.1538e+06        4.1498e+06        4.1579e+06
2592.9        1.0952e+06        1.0887e+06        1.1017e+06
4441.7        2.8521e+06        2.8513e+06        2.8529e+06
4513.0        2.0592e+05        2.0455e+05        2.0730e+05
6777.5        1.1013e+06        1.1006e+06        1.1020e+06
6790.9        3.9913e+06        3.9879e+06        3.9947e+06
6858.2        1.3100e+06        1.3078e+06        1.3122e+06
9547.8        1.2492e+06        1.2469e+06        1.2514e+06
10234.7       3.4336e+06        3.4209e+06        3.4463e+06
10398.7       4.3217e+05        3.2860e+05        6.3104e+05
12744.2       4.5274e+05        4.5177e+05        4.5371e+05
14211.3       2.0254e+06        2.0081e+06        2.0430e+06
16123.0       2.1225e+06        2.1173e+06        2.1276e+06
16135.8       4.6547e+06        4.6529e+06        4.6564e+06
16370.3       1.4781e+06        1.4762e+06        1.4800e+06
18689.2       4.5978e+06        4.5891e+06        4.6064e+06
20299.5       4.1859e+05        4.1375e+05        4.2353e+05
20364.6       1.1099e+06        1.0630e+06        1.1612e+06
21418.2       4.5814e+06        4.5718e+06        4.5911e+06
23631.9       2.8907e+06        2.8700e+06        2.9116e+06
24797.4       1.1241e+06        1.1121e+06        1.1363e+06
27214.5       2.1015e+06        2.0752e+06        2.1285e+06
28947.3       2.1285e+06        2.1162e+06        2.1410e+06
29054.7       1.4873e+06        1.4631e+06        1.5124e+06
29143.8       4.1250e+06        4.1050e+06        4.1453e+06
29647.5       4.5456e+05        4.4215e+05        4.6768e+05
31135.4       7.5136e+05        7.3331e+05        7.7033e+05
32013.4       1.1846e+06        1.1565e+06        1.2140e+06
Attachment 9: ringdown_rawdata_2016_10_19.m
%% Parameters
prefix = '2016_10_19';  % name of the folder where result will be saved
gps0 = 1160972805;      % GPS time of clean data before excitation
gps1 = 1160972852;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 6;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement

... 274 more lines ...
Attachment 10: ringdown_rawdata_2016_10_20.m
%% Parameters
prefix = '2016_10_20';  % name of the folder where result will be saved
gps0 = 1161012900;      % GPS time of clean data before excitation
gps1 = 1161012972;      % GPS time right after excitation
dt = 30;                % how much data to be used to search peaks

minsnr = 6;             % minimum peak SNR
minfr = 1000;           % minimum peak frequency
Dt = 3600;              % total amount of time for the ringdown measurement

... 274 more lines ...
ELOG V3.1.3-