 Tue Oct 30 16:55:40 2007, tobin, Routine, , Drag-wiping perfected
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Steve, Tobin
Steve procured an assortment of syringes from the bio storeroom and we practiced drag-wiping the SOS in the flow bench. Using a 50 microliter Hamilton |
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Thu Nov 15 18:36:48 2007, John, Summary, , PSL table work
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| I've rotated the lambda/2 plate to 340deg (from 6 deg) and blocked one arm of the Mach-Zender. Undo both if you need to. |
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Wed Nov 28 12:43:53 2007, Andrey, Bureaucracy, , Here was the PDF-file of my presentation
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I was making a report with powerpoint presentation during that Wednesday's 40-m meeting.
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Thu Dec 27 12:12:02 2007, pkp, Update, , Update on GigE Camera
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So I finally got the linux software to compile on mafalda. I got the software to dump all the information regarding the camera onto a file. I tried to take
a tiff snap and came up empty. So I looked at the configuration file and realized that the camera thinks that the frame-rate is a nan. Am reading up the
manual to fix the frame-rate manually and then will attempt to take another snap.
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Wed Jan 23 09:27:55 2008, steve, Update, , etmy sus damping restored 
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| Seismis event trips etmy |
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Fri Jun 20 02:20:33 2008, Yoichi, Update, , PMC transmittance degradation
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The PMC transmitted light power has been degrading constantly for last two weeks (see the attachment 1).
I went down to 2.55V.
The output of the MOPA is constant during this period. More strangely, the reflected power from the PMC is also constant.
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Wed Jun 25 09:46:45 2008, Sharon, Update, , Adaptive Filters
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I have been learning about different methods for applying adaptive filters to improve the Mode Cleaner lock in specific, and other LIGO systems in general.
Finding the exact number of coeffs we would like to apply for our FIR adaptive filter is very important to the efficiency of the filter. Getting this number
higher might improve the accuracy of the filter, but costs time we do not have. Another important number to find is the step size. The step size is the |
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Thu Jun 26 18:29:44 2008, Jenne, Update, , MC Back online
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Jenne, Rob, Yoichi
I was playing with the Mode Cleaner earlier today, working on measuring the effect of the new filter (see next post for loop gain measurements etc.), and |
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Wed Jul 16 11:26:47 2008, Max Jones, Update, , This Week
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Baffles.
I got a battery for the magnetometer today which is slightly too large (~2 mm) in one dimension. Not sure what I'm going to do.
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Mon Jul 21 09:52:05 2008, Sharon, Update, , Adaptive code changes
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Thanks to Alex, we now save the coefficients of the adaptive filter every cycle. When we choose ENABLE: OFF on the MEDM screen, suppressing the signal to
the MC1, we stop and save the last coefficients. When enabling it again, it starts from the last coefficients saved. I will take some measurements today
to check how this contributes to the adaptation rate. If you change the number of taps or the number of AUX channels, the coefficients are again set to |
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Mon Jul 21 19:48:57 2008, Sharon, Update, , how tp restart C1ASS
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How to restart C1ASS:
1. reboot
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Wed Jul 23 10:47:05 2008, Sharon, Update, , Weekly update
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This week I spent some time with Alex who updated the adaptive code to save the filter's coeffs all the time, stop when I open the loop, and reload the
latest coeffs. when I start it again.
The point was to minimize the adaptation rate. Unfortunately, seems it is making some filters go wild, so it is not in use yet.
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Wed Jul 23 13:52:26 2008, Sharon, Update, , MEDM changes
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There is a new MEDM screen now when you go from c1ass>top>pem.
Instead of having 12 "mini filters" screens go to 8 outputs (with the wrong correlation impression from the table), we have a 24X8 matrix.
This matrix is there so you could choose which noise signals you want to send to the adaptive code. When you indicate the number of noise channels you |
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Fri Jul 25 13:30:53 2008, Sharon, Update, , Changes in ASS computer
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I editted the simulink diagram of the ASS computer so it now has 2 more channels reading 2 sets of the FIR coefficients to match Alex's changes in the C
code.
The new simulink has already been compiled and can be found in /cvs/cds/caltech/users/alex/cds/advLigo/src/epics/simLink/ass.mdl
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Fri Jul 25 17:32:46 2008, Sharon, Update, , ASS computer
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So, it seems a bit too complicated getting the coefficients the way I wanted it to happen (simulink-.ini...).
I returned everything to the way it was and it's all working. The new plan is to choose the specific channel I want to find its instantanous coefficients,
let the adaptive code run for a while, setting mu and tau to zero (freezing the coefficients), and exciting the noise signal channel taking the transfer |
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Mon Jul 28 12:02:32 2008, Sharon, Update, , accelerometers settings
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Jenne, Sharon
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Mon Jul 28 17:58:05 2008, Sharon, Update, , TOP screen changes
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I wanted to test the adaptive code with a downsampling rate of 32 instead of 16. To do this I entered a 32 Hz ((2048/32)/2 - match Nyquist Freq.) low pass
filter on the ERROR EMPH, MC1 and the relevant PEM channels. |
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Tue Jul 29 21:04:55 2008, Sharon, Update, , OSEM's Power Spectrum 8x
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| From 16:30 this afternoon |
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Wed Jul 30 12:36:19 2008, Sharon, Update, , Weekly update
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This week included many computer's issues. I tested Alex's new C code (the one that saves the FIR coefficients and restores them when you start running
the code again). Seems there is an improvement in the adaptation time, but not a significant one (more details on the coming report). I had to recompile
simulink and the FB whenever I wanted to find a solution for taking the record of those coefficients. This is so I could simulate the adaptive filter with |
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Fri Aug 8 11:04:34 2008, Sharon, Update, , MCL Wiener filter
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I took some old data from Rana and converted the units of the Weiner filter to m/m so to make the effect of the seismometer and accelerometers more obvious.
The data is in counts, and so to convert to m this is what I did:
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Fri Aug 15 16:45:43 2008, Sharon, Update, , Converting from FIR to IIR
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I have been looking into different techniques to convert from FIR to IIR. This is so we can see how effective the adaptive FIR filter is in comparison to
an IIR one with fewer taps.
For now I tried 2 matlab functions: Prony and stmcb (which works on LMS method).
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Tue Aug 19 10:36:34 2008, Sharon, Update, , Calibrating accelerometers
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I took apart the accelerometers near MC1 and MC2.
The 2 sets of 3 accelerometers are now covered by a box on the floor. Please try not to move them... I will place it all back once I am done calibrating. |
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Tue Aug 19 17:00:19 2008, Sharon, Update, , Wiener TF calibration - update
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[I]This is an update for post 814[/I]
I added the calibration gains I got for the accelerometers (I realize I am just calibrating the accelerometers to themselves and this is not m/m exactly |
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Tue Aug 19 17:15:34 2008, Sharon, Update, , MEDM
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| I plugged in the gains I got for the accelerometers in the accelerometers' filters in the PEM screen of the adaptive filter |
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Wed Aug 20 17:02:01 2008, Sharon, Update, , More FIR to IIR
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I tested another method for converting from FIR to IIR other than the 2 mentioned in post 841.
I got this one from Yoichi, called poles fitting, you can read about it more if you want at: http://www.rssd.esa.int/SP/LISAPATHFINDER/docs/Data_Analysis/DA_Six/Heinzel.pdf.
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Fri Aug 22 13:58:39 2008, Sharon, Summary, , Trend of the Wiener TF
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In order to understand if we really need an adaptive filter, I used old data of MC_L and the accelerometers and seismometer to see if the Wiener (ideal)
TF between MC_L and the others really changes all the time.
Two tests I made:
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Wed Sep 3 18:45:01 2008, Alberto, Configuration, , PD3 gain
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Alberto, Yoichi,
We found that the PD3 servo was unstable with a gain of 1, so we switched it to 0.5 |
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Mon Mar 30 12:29:17 2009, Yoichi, Configuration, , MC1 glitches not seen during the weekend
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The attached is the MC trend for the past 12 hours.
There is no MC1 glitches in the OSEM signals. Moreover, the total amplitude of the drift is smaller than it used to be (now the amplitude is less than
100 but it used to be a few hundreds).
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Thu May 7 17:59:23 2009, Alberto, Configuration, , MC WFS
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This afternoon the MC could not get locked.
I first checked the Osems values at the MC mirrors and compared them to the trend of the last
few hours. That showed that the alignment of the mirrors had slightly changed. I then brought each mirror back to its old alignment state.
That
let the LSC loop lock the MC, although the reflected power was still high (1.5V) and the WFS control wouldn't engage.
Since |
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Mon Jul 13 16:59:10 2009, Zach, Update, , GigE Phase Camera
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Today, I moved the router from on top of the PSL into the control room in order to perform dark field tests on the GC650 (which I also moved).
The GC750 along with the lens that was on it and the mount it was on has been lent to Ricardo's lab for the time being. I successfully triggered
the GC650 externally and I also characterized the average electronic noise. For exposure times less than 1 microsecond, the average noise contribution |
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Mon Jul 27 14:43:34 2009, Chris, Update, , Photodetectors
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I found two ThorLabs PDA55 Si photodetectors that says detect visible light from DC to 10MHz that I'm going to use from now on. I don't know how
low of a frequency they will actually be good to. |
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Fri Aug 14 18:33:02 2009, Clara, Update, , Record of Accelerometer and Seismometer Movements
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Rather than make a new elog post every time I move something, I'm going to just keep updating this Google spreadsheet, which ought to republish every
time I change it. It's already got everything I've done for the past week-ish. The spreadsheet can be accessed here,
as a website, or here, as a pdf. I will still post something |
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Tue May 25 17:04:37 2010, Kevin, Update, , Beam Profile After Mode Cleaner
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I fit the data from the beam profile that Jenne measured on 5/21/2010. The distances are measured from halfway between MC1 and MC3 to the beam scanner.
The fits give the following where w0 is the waist size and z0 is the distance from the waist to halfway between MC1 and MC3.
For the horizontal profile: |
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Tue Jun 1 18:39:59 2010, Nancy, Update, , Lead spheres for the seismographs
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the lead spheres that were placed below the granite slab have been flattened by hammering to have lesser degree of wobbling of the slab.
the height of each piece, and the flatness of their surfaces was checked by placing another slab over them and checking by the spirit level. |
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Wed Jul 7 12:45:00 2010, nancy, Update, , Weekly Update
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Wednesday after the meeting - Started report, learnt mode cleaner locking from Kiwamu and Rana, saw how to move optics on the tables with Rana and kiwamu.
Thursday - Made the report
Tuesday - report. |
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Sun Sep 12 23:02:53 2010, valera, Update, , PMC mode matching
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Kiwamu and I found that the first lens in the PMC mode matching telescope was mislabeled. It is supposed to be PLCX-25.4-77.3-C and was labeled as such
but in fact it was PLCX-25.4-103.0-C. This is why the PMC mode matching was bad. We swapped the lens for the correct one and got the PMC visibility of
82%. The attached plot shows the beam scans before and after the PMC. The data were taken with the wrong lens. The ABCD model shown in the plot uses the |
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Sun Sep 12 23:16:52 2010, valera, Update, , FSS mode matching
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The attached plot shows the beam scans of the beam leaking from the back mirror of the PMC to the BS cube that first turns the S-pol beam 90 deg to the
AOM and then transmits the AOM double passed and polarization rotated P-pol beam to the reference cavity. The beam from the PMC is mode matched to the
AOM using a single lens f=229 mm. The ABCD file is attached. The data were taken with VCO control voltage at 5 V. We then reduced the voltage to 4 V to |
 Mon Sep 13 00:19:32 2010, rana, Update, , VCO Driver Output power v. slider control voltage
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I measured the RF power output of the VCO Driver box as a function of slider value. I measured using the Gigatronics Handheld power meter and connected
to the AOM side of the cable after the white Pasternak DC block.
* at low power levels, I believe the waveform is too crappy to get an accurate reading - that's probably why it looks non-monotonic. |
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Wed Sep 15 19:29:13 2010, valera, Summary, , PSL power budget
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Location
Power (mW)
NPRO - after HWP
252
Rejected by input FI polarizer
38
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Fri Sep 17 01:36:14 2010, valera, Update, , PMC line width
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The attached plots show the PMC cavity line width measurement with 1 mW and 160 mW into the PMC. The two curves on each plot are the PMC transmitted
power and the ramp of the fast input of the NPRO. The two measurements are consistent within errors - a few %. The PMC line width 3.5 ms (FWHM)
x 4 V / 20 ms (slope of the ramp) x 1.1 MHz / V (NPRO fast actuator calibration from Innolight spec sheet) = 0.77 MHz. |
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Thu Nov 11 15:27:43 2010, valera, steve, Configuration, , ISS AOM installed
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We installed the ISS AOM in the PSL. The AOM was placed right after the EOM. The beam diameter is ~600 um at the AOM. The AOM aperture is 3 mm.
We monitored the beam size by scanning the leakage beam through the turning mirror after the AOM. The beam diameter changed from 525 um to 515
um at a fixed point. We decided that the AOM thermal lensing is not large enough to require a new scan of the mode going into the PMC and we can |
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Thu Feb 17 22:51:04 2011, josephb, valera, Summary, , dither alignment model
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We made a model for the dither angular stabilization system c1ass.mdl. The attached file shows the diagram.
The idea is to dither a combination of 6 optics (ETMs, ITMs, PZTs) at different frequencies and demodulate three PDs (TRX, TRY, REFL11I). Then
form the DOFs from demodulted signals, filter, and send each DOF to a combination of optics. |
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Tue Feb 22 00:18:47 2011, valera, Configuration, , c1ioo and c1ass work and related fb crashes/restarts
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I have been editing and reloading the c1ioo model last two days. I have restarted the frame builder several times. After one of the restarts on Sunday
evening the fb started having problems which initially showed up as dtt reporting synchronization error. This morning Kiwamu and I tried to restart the
fb again and it stopped working all together. We called Joe and he fixed the fb problem by fixing the time stamps (Joe will add details to describe the |
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Tue Feb 22 23:11:42 2011, valera, Update, , new medm screens: C1ASS.adl and C1MCASS.adl
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Wed Feb 23 16:34:42 2011, valera, Configuration, , pmc lens staged
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I put the PMC last mode matching lens (one between the steering mirrors) on a translation stage to facilitate the PMC mode matching.
Currently 4% of incident power is reflected by the PMC. But the reflected beam does not look
"very professional" on the camera to Rana - meaning there is too much |
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Wed May 4 13:51:51 2011, valera, Configuration, , Intermittent MC3 UL PD signal
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The attached plot shows the 30 day trend of the MC3 UL PD signal. The signal dropped to zero at some point but now it is close to the level it was a
few weeks ago. There still could be a problem with the cable.
The rest of the MC1,2,3 PD signals looked ok. |
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Wed May 4 15:22:39 2011, kiwamu, Update, , Re: Intermittent MC3 UL PD signal
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I went push all the possible connectors for the MC3 shadow sensors including the SCSIs, flat cables and satellite
box.
Also I put screws on them so that they won't become loose any more. |
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Mon Jul 11 10:10:31 2011, Ishwita, Configuration, , AA board
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The AA board shown in attachment 1 will be used in the seismometer hardware setup. A cartoon of this setup is shown in attachment 2.
BNC connectors are required for the seismometer breakout boxes. So the four-pin LEMO connectors present in the AA board were removed and panel
mount BNC connectors were soldered to it. Red and blue colored wires were used to connect the BNC connectors to the board. Red wire connects the center |
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Wed Jul 20 11:42:47 2011, Ishwita, Manuel, Update, , Weekly summary
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We gave a white-board presentation on derivation of formula for optimum Wiener filter coefficients and wrote a latex document for the same.
relevant elog entry
We enjoyed drilling the cover of the AA board and fixing it.
The AA board was fixed on rack 1X7 with Jenne's help. relevant elog entry
We |
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Thu Jul 21 23:36:51 2011, Jenny, Update, , Fitting beam waist with MATLAB
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I am starting work on the PSL table at the 40m. My goal is to lock the laser coming from the nearby table to the FP cavity and get a measurement of
the response to a temperature step on the surrounding can.
I have to mode match the beam to the cavity. Specifically, I have to mode match to the beam coming from the PMC through the EOM to the polarizing |