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ID Date Author Type Categoryup Subject Text Attachments
  13635   Fri Feb 16 01:09:55 2018 gautamUpdateALSEX green locking duty cycleI have been puzzled as to why the duty
cycle of the EX
green locks are much
 GreenLock8hrs.png 
  13636   Fri Feb 16 01:34:40 2018 gautamUpdateALSD0902745 in-situ testingHaving implemented the changes to the audio
amplifier stage, I re-installed this unit
at the LSC rack, and did some testing. 
 BeatMouthX_20180216.pdfIMG_5134.JPG 
  13644   Tue Feb 20 23:08:27 2018 gautamUpdateALSD0902745 in-situ testingAttachment #1 shows
the ALS noise measurement today. Main differences
from the spectrum posted last week is that
 BeatMouthX_20180220_diffOut.pdf 
  13648   Thu Feb 22 00:09:11 2018 gautamUpdateALSD0902745 in-situ testingI thought a little bit about the design
of the preamp we want for the demodulated
ALS signals today. The requirements are:
 daughterBoard_TF.pdfdaughterBoard_noise.pdfIMG_6906.JPG 
  13655   Sun Feb 25 00:03:12 2018 gautamUpdateALSDaughter board prototypingUsing one of the prototype  schematic.pdfdaughterBoard_TF.pdfdaughterBoard_noise.pdfTEK00000.PNGdaughterBoard_noise.pdf 
  13657   Mon Feb 26 20:55:56 2018 ranaUpdateALSDaughter board prototypingLooks good.

* for bypass type applications,
you don't have to use Wima caps (which
  
  13658   Tue Feb 27 21:10:45 2018 gautamUpdateALSDaughter board testingI thought a little bit about the next steps
in testing the daughter board. The idea is
to install this into the existing 1U chassis
 IMG_6912.JPGIMG_6913.JPGIMG_6914.JPG 
  13661   Wed Feb 28 19:13:25 2018 gautamUpdateALSADC test for differential receiving in c1lsc[koji,
gautam]

we did a bunch of tests to figure
 c1lsc_ADCtest.png 
  13663   Fri Mar 2 01:45:06 2018 gautamUpdateALSnew look ALS electronicsI spent today making another daughter board
(so that we can use the new scheme for I
and Q for one arm), testing it (i.e. measuring
 IMG_6916.JPG 
  13666   Mon Mar 5 17:27:34 2018 gautamUpdateALSnew look ALS electronics - characterizationI did a quick test of the noise of the
new ALS electronics with the X arm ALS. Attachment
#1 shows the results - but something looks
 BeatMouthX_20180305_diffOut.pdf 
  13668   Thu Mar 8 00:40:25 2018 gautamUpdateALSnew look ALS electronics - characterizationI am almost ready for a digital test of
the new ALS electronics. Today, Koji and
I spent some time tapping new +/-24VDC DIN
 BeatMouthX_20180305_diffOut.pdf 
  13673   Thu Mar 8 19:38:37 2018 gautamUpdateALSdigital unwhitening of daughter boardI made a LISO fit of the measured TF of
the daughter board, so that I can digitally
invert the daughter board whitening. Results
 TFfit.pdf 
  13674   Thu Mar 8 23:50:27 2018 gautamUpdateALSFirst look at new ALS electronics
Locked single arms, dither aligned,
and saved offsets to EPICS (slow) sliders
in anticipation of having to reboot all vertex
 BeatMouth_OOL.pdf 
  13675   Fri Mar 9 01:07:01 2018 gautamUpdateALSFirst look at new ALS electronics[koji,
gautam]
 ALS_vs_POXnoise.pdf 
  13679   Mon Mar 12 22:08:31 2018 gautamUpdateALSNoisy POX[kevin, gautam]

we tested my noisy POX hypothesis
tonight. By locking the single arm with POX,
 NoisyPOX_20180312.pdf 
  13680   Mon Mar 12 23:57:31 2018 gautamUpdateALSNoisy POX[kevin,
gautam]
 NoisyPOXandPOY_20180312.pdfnoisyPOX_Jan2018.pdf 
  13688   Mon Mar 19 15:02:29 2018 gautamUpdateALSNoisy MC sensingThe working hypothesis, since the excess
noise in single arm locks is coherent between
both arms, the excess sensing noise is frequency
  
  13749   Thu Apr 12 18:12:49 2018 gautamUpdateALSNPRO channels hijackedSummary:


Today,
the measured IR ALS noise for the X arm was
dramatically improved. The main change was
 IR_ALS_20180412.pdfBeatMouthDrift.pngETMX_20180416.jpg 
  13751   Fri Apr 13 11:02:41 2018 gautamUpdateALSEX fiber polarization driftAttachment #1  EX_pol_drift.png 
  13752   Fri Apr 13 16:59:12 2018 gautamUpdateALSEX green mode-matchingTHIS CALCULATION   
  13753   Fri Apr 13 17:56:26 2018 gautamUpdateALSFibers switched outI swapped the EX fiber for the PSL fiber
in the polarization monitoring setup. There
is a lot more power in this fiber, and one
  
  13754   Sat Apr 14 14:42:09 2018 gautamUpdateALSFibers switched outIt looks like the drift in polarization
content in the PSL pickoff is actually much
higher than that in the EX pickoff. Note
 PSLdrift.png 
  13757   Tue Apr 17 14:08:29 2018 gautamUpdateALSFibers switched outA follow-up on the discussion from today's
lunch meeting - Rana pointed out that rotation
of the fiber in the mount by ~5degrees cannot
 PSL_fluctuations.png 
  13773   Fri Apr 20 00:26:34 2018 gautamUpdateALSFibers switched outSummary:

  
  13779   Sat Apr 21 20:25:12 2018 gautamUpdateALSPSL fiber pickoff statusSeems like there is still a bit of variation
in the power in the two polarizations, though
it is much smaller now, at the ~5% level
 PSL-beatMouthPickoff.png 
  13784   Tue Apr 24 11:31:59 2018 gautamConfigurationALSProposed changes to EX fiber couplingMotivation:
I want to make another measurement of the
 EX_fiber_MM.pdfEX_fiber_changes.png 
  13786   Tue Apr 24 18:54:15 2018 gautamConfigurationALSProposed changes to EX fiber couplingI started working on the EX table. Work
is ongoing so I will finish this up later
in the evening, but in case anyone is wondering
  
  13789   Wed Apr 25 19:09:37 2018 gautamConfigurationALSNew look EX Fiber couplingSummary:

I implemented most of the things
outlined in my previous elog.
 EX_fiber_MM.pdfIMG_6977.JPGIMG_6972.JPGIMG_6974.JPGIMG_6976.JPG 
  13791   Thu Apr 26 11:24:50 2018 gautamConfigurationALSNew look EX Fiber coupling - pol stabilityHere is a first look at the overnight stability.
For the temperature, I used the calibration
I found in the old psl database file, seems
 polStab.pdf 
  13792   Thu Apr 26 18:58:21 2018 BruceConfigurationALSNew look EX Fiber coupling - pol stability    
  13796   Fri Apr 27 01:36:02 2018 gautamConfigurationALSIR ALS noise performanceSummary:

My goal was to do some further
characterization of the IR ALS system tonight.
 2018_04_BeatMouth_POX.pdf2018_04_BeatMouth.pdfALSSpecgram.pdfALS_ASD.pdfALSstab.pdf 
  13807   Wed May 2 21:39:33 2018 gautamConfigurationALSIR ALS for EYThe new K6XS mounts I ordered have arrived.
I want to install one of them at the Y-end.
I can't find a picture of the current
  
  13817   Fri May 4 21:17:57 2018 gautamConfigurationALSBeathMouth pulled out of PSL tableI have been puzzled about the beat note
level we get out of the BeatMouth for some
time.
  
  13824   Tue May 8 00:40:51 2018 gautamConfigurationALSBeathMouth pulled out of PSL tableSummary:

I did some more BeatMouth characterization.
My primary objective was to do a power budget.
 IMG_6986.JPGIMG_6987.JPG 
  13886   Thu May 24 13:06:17 2018 gautamConfigurationALSDFD noisesSummary:


The DFD noise floor is
~0.5Hz/rtHz
 DFDcalib.pdfDFD_NB.pdf 
  13889   Thu May 24 19:41:28 2018 gautamConfigurationALSBeathMouth reinstalled on PSL tableSummary:


DC light power incident
on beat PD is 
  
  13890   Thu May 24 20:31:03 2018 gautamConfigurationALSDFD noisesA
couple of months ago, I took 21 measurements
of the delay line transfer function. As shown
 TF_X_mag.pdfTF_X_phase.pdf 
  13955   Wed Jun 13 12:21:09 2018 gautamUpdateALSPDFR laser checkoutI want to use the Fiber Coupled laser from
the PDFR
system to characterize the response of
  
  13957   Wed Jun 13 22:07:31 2018 gautamUpdateALSBeatMouth PDFR measurementSummary:

Neither
 IMG_7056.JPGBeatMouthPDFR.pdfBeatMouth_PDFRdata.tgz 
  13973   Fri Jun 15 14:22:05 2018 gautamUpdateALSBeatMouth PDFR measurementI did the measurement with the BeatMouth
open today. Main changes:


Directly pipe the RF output
 BeatMouthPDFR.pdfBeatMouth_PDFRdata.tgz 
  14468   Wed Feb 20 23:55:51 2019 gautamUpdateALSALS delay line electronicsSummary:

Last year, I worked
on the ALS delay line electronics, thinking
 delayLineDemod.pdf.zip 
  14475   Thu Mar 7 01:06:38 2019 gautamUpdateALSALS delay line electronicsSummary:

The restoration of the delay-line
electronics is complete. The chassis has
  
  14477   Tue Mar 12 22:51:25 2019 gautamUpdateALSALS delay line electronicsThis
Hanford alog may be of relevance as we
are using the aLIGO AA chassis for the IR
  
  14478   Wed Mar 13 01:27:30 2019 gautamUpdateALSALS delay line electronicsThis test was done, and I determine the
frequency discriminant to be 
 DFDcal.pdfDFDnoise.pdf 
  14479   Thu Mar 14 23:26:47 2019 AnjaliUpdateALSALS delay line electronicsAttachment #1 shows the schematic of the
test setup. Signal generator (Marconi) was
used to supply the RF input. We observed
 test_setup_ALS_delay_line_electronics.pdf 
  14480   Sun Mar 17 00:42:20 2019 gautamUpdateALSNF1611 cannot be shot-noise limited?Summary:

Per the manual (pg12)
of the NF 1611 photodiode, the "Input
 PDnoise.pdf 
  14481   Sun Mar 17 13:35:39 2019 AnjaliUpdateALSPower splitter characterizationWe characterized the power splitter ( Minicircuit-
ZAPD-2-252-S+). The schematic of the measurement
setup is shown in attachment #1. The network/spectrum/impedance
 Measurement_setup.pdfTotal_loss.pdfAmplitude_unbalance.pdfPhase_unbalance.pdf 
  14482   Sun Mar 17 21:06:17 2019 AnjaliUpdateALSAmplifier characterisationThe goal was to characterise the new amplifier
(AP1053). For a practice, I did the characterisation
of the old amplifier.This test is similar
 Gain_measurement.pdfAmplifier_gain.pdfnoise_measurement.pdfnoise_characterisation.pdf 
  14486   Mon Mar 18 20:22:28 2019 gautamUpdateALSALS stability testI'm running a test to see how stable
the EX green lock is. For this purpose, I've
left the slow temperature tuning servo on
  
  14498   Thu Mar 28 19:40:02 2019 gautamUpdateALSBeatMouth with NF1611s assembledSummary:

The parts I was waiting for arrived.
I finished the beat mouth assembly, and did
 IMG_7381.JPGIMG_7382.JPGrelTF_schem.pdfdarkNoise.pdf 
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