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ID Dateup Author Type Category Subject Text Attachments
  2265   Mon Dec 17 22:13:03 2018 anchalDailyProgressTempCtrlProposed circuit for cavity temperature sensor Part 2The second stage of the amplifier for temperature
sensor would be subtractor circuits using
  2266   Wed Dec 19 11:01:00 2018 awadeDailyProgressTempCtrlProposed circuit for cavity temperature sensor Part 2Missing current excitation to RTD?

don't know if I'm missing it, or
if you've yet to add it, but can't
  2267   Wed Dec 19 14:00:55 2018 anchalDailyProgressTempCtrlProposed circuit for cavity temperature sensor Part 2About the current source:

current excitation circuit is there, it is
just in another page in the schematic. I'm
  2268   Wed Dec 19 17:47:02 2018 anchalDailyProgressTempCtrlCavity Temperature Sensor Circuit v1.1From the review of PSL:2266 and
the promises I made in PSL:2267,
I think I have fixed the circuit. Corrected
  2269   Mon Dec 24 16:52:26 2018 ranaDailyProgressTempCtrlCavity Temperature Sensor Circuit v1.1post a plot of the times series and noise

Here is a link on how to choose
  2270   Tue Dec 25 11:45:15 2018 anchalDailyProgressTempCtrlVacuum Can Temperature Sensors (AD590) transimpedance amplifier board testYesterday, I put two boards of LIGO-D1800304
with two pairs of circuits populated in each
of them for testing.
  2271   Wed Dec 26 14:09:29 2018 anchalNotesEPICSws1 unable to read/write on some EPICS channelsws1 is unable to read and write on some
EPICS channels while I can see these channels
in fb4 or acromag1. These channels are:
  2272   Fri Jan 4 16:42:28 2019 anchalSummaryNoiseBudgetLatest noisebudget update.
Since we are working on temperature
control of cavities, we worked out a hack
to still take beat note spectrum meanwhile.

  2273   Fri Jan 4 19:04:29 2019 awadeDailyProgressRFAMTime to look at RF AM and RINThat roll up in the HF range to 3 kHz hump
looks suspect. 


We need to check
  2274   Fri Jan 4 19:17:00 2019 anchalSummaryTempCtrlVacuum Can Temperature Sensors (AD590) transimpedance amplifier board test - RESULTSOver the break, the test of Vacuum Can
Temperature Sensors transimpedance circuit
was running and fb4 has logged the values.
  2275   Wed Jan 9 17:25:38 2019 anchalDailyProgressRFAMTime to look at RF AM and RINI measured RIN of the two paths yesterday
through taking spectrum of transmission PDs
and measured cross-correlation with the Beatnote.
  2276   Wed Jan 9 19:05:56 2019 anchalDailyProgressRFAMTime to look at RF AM and RINPreliminary testing

I hooked
up an HP8560E to RF port of the South FSS
Refl RFPD. I unlocked laser from the cavity
  2277   Thu Jan 10 10:39:27 2019 anchalDailyProgressNoiseBudgetNew noise budget code is ready, butThe new noise budget code is ready. However,
there are few discrepancies which still need
to be sorted. 
  2278   Thu Jan 10 11:38:53 2019 awadeDailyProgressRFAMTime to look at RF AM and RINIs
this the resonant EOM or a BBEOM driven with
an external circuit? The driving requirements
  2279   Thu Jan 10 14:19:46 2019 anchalDailyProgressRFAMTime to look at RF AM and RINI found this paper on OSA: Control
of residual amplitude modulation in Lithium
Niobate phase modulators. It suggests
  2280   Thu Jan 10 17:30:24 2019 anchalDailyProgressRFAMTime to look at RF AM and RINWe measured the modulation index of 0.142
rad when we installed the PMC (See PSL:2251).
I checked both PMC loops, none of them are
  2281   Thu Jan 10 18:52:20 2019 anchalDailyProgressRFAMTime to look at RF AM and RINI think I found the culprit. the polarizer
behind the EOM (PMC loop EOM) was a multi-order
one and hence was extremely sensitive to
  2282   Sat Jan 12 13:11:02 2019 awadeDailyProgressRFAMTime to look at beatnote after RF AM and RIN tuneupNice.  

It would be a good time to retake
the BN + cross spectrum with RIN to see if
  2283   Wed Jan 16 11:07:41 2019 anchalDailyProgressNoiseBudgetBeatnote after RF AM and RIN tuneupIntensity noise to the beatnote transfer

I resurrected
the AEOM power control lines with SMA cables
  2284   Wed Jan 16 22:07:44 2019 awade, anchalDailyProgressPLLPLL noise from the Marconi 2023A FG[awade, anchal]

This is not a detailed post as
I didn't collect data.  We need
  2285   Thu Jan 17 11:55:12 2019 anchalSummaryTempCtrlVacuum Can Temperature Sensors (AD590) transimpedance amplifier board noise testI wanted to take a direct spectrum noise
measurement of the circuit. However, if I
have simply hooked the output of the circuit
  2286   Fri Jan 18 13:10:02 2019 anchalDailyProgressPLLPLL noise from the Marconi 2023A FGI took the noise spectrum of beat note
in PLL when it is fed with a low noise Wenzel
Crystal Oscillator of frequency 24.483 MHz
  2287   Mon Jan 21 19:01:11 2019 anchalNotesPLLPLL Transfer Function and Noise StudyI see that we were lacking in complete
documentation of PLL transfer function and
noise analysis. I made this document for
  2288   Tue Jan 22 19:04:51 2019 anchalDailyProgressPLLNew Focus 1811-FC Dark noise MeasurementWe suspected if the wideband RF detector
Focus 1811-FC could be the source of
  2289   Tue Jan 22 20:26:18 2019 awadeDailyProgressTempCtrlRunning relay controller overnight on refcavsBeat note is still not under control. Its
drifting at 10 kHz/min, too much for a lower
range marconi measurement.
  2290   Wed Jan 23 11:28:53 2019 awadeDailyProgressTempCtrlCorrecting BN after running relay controller overnight on refcavsThis test relay test was a failure. 
I got impatient late last night and
downed the midpoint diff heating to 0.5732
  2291   Wed Jan 23 11:43:02 2019 awade, anchalDailyProgressPLLNew Focus 1811-FC Dark noise MeasurementThe first measurement here seems like a
smoking gun for limiting noise.  A mixer
down converted noise of 1.3 µV/rtHz (directly
  2292   Wed Jan 23 18:13:48 2019 anchal and awadeDailyProgressFSSFSS Gain and Offset tuningToday we checked FSS Common path and Fast
path transfer functions to see unity gain
frequencies and any possible optimizations.
  2293   Thu Jan 24 12:38:47 2019 anchalDailyProgressNoiseBudgetBeat Note Noise Spectrum after tuning FSS LoopPLL Readout Noise and Open-Loop
Transfer Function:

remeasured dark noise of wideband photodetector
  2294   Thu Jan 24 14:24:10 2019 awadeDailyProgressTempCtrlCustom implementation of PIDLocker script for finer control of intergration on cav heatersProbably a lot of our problems of the PID
tuning of the cavity temperature controls
(for controlling BN freq) come back back
  2295   Fri Jan 25 10:46:24 2019 awadeDailyProgressTempCtrlPID locking of cavity heaters to BNTesting of this seems to confirm that lower
intergrator values are the way to go. 
We had excellent locking with <1.2 kHz/min
  2296   Fri Jan 25 15:45:48 2019 anchalDailyProgressTempCtrlPID locking of cavity heaters to BNAbout BN slope detector: I
just made few extra EPICS channels to do
this. But acromag1 hasn't rebooted since
  2297   Mon Jan 28 10:56:49 2019 awade and anchalDailyProgressNoiseBudgetNoisebudget with Resonant Beat Note Photo Detector - Touching new lowsShot Noise of Photocurrent:

0.5 mW power is falling on the wideband beat
note photodetector New
  2298   Tue Jan 29 17:47:14 2019 anchalDailyProgressTempCtrlCavity Temperature Sensor Breadboard Circuit Noise AnalysisHere are the noise spectrum and time series
plots that were asked of me ages ago. Apologies
for the delay. I've also attached the
  2299   Wed Jan 30 12:17:05 2019 ranaDailyProgressTempCtrlCavity Temperature Sensor Breadboard Circuit Noise Analysisthat's a good start, but we don't
care about the noise above 10 Hz. So
you should re-take the data and plot
  2300   Wed Jan 30 15:07:32 2019 awade, anchalHowToFSSShot noise in FSS loops?The FSS at some point is going to be limited
by shot noise. I understand that the apparent
frequency noise should go as [1]:
  2301   Fri Feb 1 14:59:01 2019 awade, anchalHowToFSSNoise talliesWe've hit a flat (white) noise floor
at around 70 mHz/rtHz.  Time to tally
all the unaccounted for noises.
  2302   Fri Feb 1 20:20:11 2019 awadeHowToFSSModifying North FSS EOM pathI'm implementing the suggested cap
and resistor updates in the last post (PSL:2301).  
  2303   Tue Feb 5 11:40:02 2019 awadeHowToFSSModifying South FSS boostShortening the capacitor leads on U7 boost

checked the boost stage on U7 of LIGO-D040105-C on
the south path box (37 MHz).  It appears
  2304   Tue Feb 5 20:39:52 2019 anchalSummaryFSSComplete model of TTFSS box with TF and crossover analysisI'm attaching the first results of
the transfer function from liso model
of complete TTFSS box. I've also attached
  2305   Wed Feb 6 19:13:06 2019 anchalSummaryFSSComplete model of TTFSS box with TF and crossover analysisI added some more graphs to our FSS

I modeled AD602 variable
  2306   Wed Feb 6 21:30:24 2019 awadeSummaryFSSComplete model of TTFSS box with TF and crossover analysisHmm... Last estimate of V_rms applied to
EOM can't be true.  

If laser frequency noise is 
  2307   Thu Feb 7 10:33:27 2019 anchalSummaryFSSComplete model of TTFSS box with TF and crossover analysis


  2308   Tue Feb 26 02:45:20 2019 anchalNotesComputersMigrating epics channels from acromag1 to c3iocserverWe have been thinking for a while to migrate
all epics channels from acromag1 ( to
c3iocserver ( which is rack mount
  2309   Tue Mar 12 17:04:03 2019 anchal and awadeSummaryComputersMigrating epics channels from acromag1 to c3iocserver
The migration of all EPICS channel
hosting and all python programmes has been
done from Acromag1 to C3IOCServer. Now Acromag1
  2310   Sun Mar 17 18:28:06 2019 awade and anchalSummaryComputersMigrating epics channels from acromag1 to c3iocserver: killing acromag1 servicesWandered into the PSL just now.  Slow
controls were going wild.  Traced it
back to the fact that acromag1 and its auto-restarting
  2311   Tue Mar 19 16:39:20 2019 anchalDailyProgressFSSNeed to track down 60 Hz spike source in FSSThe bad news...

were curious on actual actuation signal being
sent to EOM by the TTFSS boxes.
  2312   Sat Mar 23 21:50:40 2019 anchalSummaryElectronics EquipmentPower tripping incident and follow-upThis week on 19th March in the evening,
I was working on replacing the GND connections
of the power supply with thicker wires and
  2313   Wed Apr 3 16:23:26 2019 anchalDailyProgressPMCRehabilitation of PMCsSince the last incident of power
supply tripping, I tested all photodiodes
and electronics in the lab one by one. During
  2314   Thu Apr 4 15:33:34 2019 anchalDailyProgressPMCRehabilitation of PMCsToday, I tried to replace the Reflection
Photodiode on South PMC with another 14.75
MHz Resonant (which from test port analysis
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