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ID Date Author Type Categorydown Subject Text Attachments
  15037   Wed Nov 20 01:07:18 2019 gautamUpdateLSCLocking - progressSummary:


CARM offset was reduced
to 0 with the PRMI locked.
TRY
 PRFPMI.png 
  15038   Wed Nov 20 12:14:17 2019 gautamUpdateLSCLocking - progressI took a look at the TRX/TRY RIN reported
in the single arm POX/POY lock, and compared
the performance of the two available PDs
 TRX_TRY_comparison.pdf 
  15039   Wed Nov 20 17:20:24 2019 YehonathanUpdateLSCQPD Investigation{Gautam, Yehonathan}

In search of the source of discrepancy
between the QPD readings in the X and Y arms,
  
  15040   Wed Nov 20 17:52:00 2019 gautamUpdateLSCQPD MEDM screen updateKoji and I had noticed that there was some
discrepancy between the switchable gain stages
of the EX and EY QPDs. Sadly, there was no
 newLookQPD.pngTRX_TRY_comparison.pdfIMG_8186.JPG 
  15041   Wed Nov 20 21:29:28 2019 gautamUpdateLSCPRG ~13After the QPD fix, both arms report consistent
buildup - see Attachment #1. The peak values
touch ~250, corresponding to a PRG of ~13.
 PRG13.pdf 
  15042   Thu Nov 21 12:46:22 2019 gautamUpdateLSCCM board studyIn preparation for trying out some high-bandwidth
Y arm cavity locking using the CM board,
I hooked up the POY11_Q_Mon channel of the
 YARM_CMslow.pdf 
  15043   Thu Nov 21 13:14:33 2019 KojiUpdateLSCCM board studyOne of the differences between the direct
POY and the CM_SLOW POY is the presence of
the CM Servo gain stages. So this might mean
  
  15044   Thu Nov 21 19:08:58 2019 gautamUpdateLSCHigh BW lock of Y arm length to PSL frequencySummary:

The Y arm cavity length was locked
to the PSL frequency with ~26kHz
 highBW_POY.pdfCM_UGF.pdfIN2_ACcoupling.pdf 
  15045   Fri Nov 22 00:54:14 2019 gautamUpdateLSClocking notes[KA, GV]

There was no shaking (that disturbed
the locking) tonight!
 ALSnoiseIncrease.pdf 
  15046   Mon Nov 25 19:11:22 2019 gautamUpdateLSCALS noise re-lookI re-checked the ALS noise in the following
configurations:


PRM is misaligned.
Michelson
 ALSnoise.pdf 
  15049   Tue Nov 26 17:07:41 2019 gautamUpdateLSCPOX / POY calibrationSummary:

Since we are using the POX and
POY photodiodes as out-of-loop sensors for
 POX_POY_sensorNoise.pdfALSnoise_20191125.pdf 
  15050   Tue Nov 26 18:16:08 2019 ranaUpdateLSCPOX / POY calibration...maybe the opto-mechanical
CARM plant
  
  15051   Wed Nov 27 12:16:52 2019 gautamUpdateLSCITMX and ITMY OSEMs with low and high circulating powerSummary:

The ITMX OSEMs report elevated
noise in the 10-100 Hz band when we have
 ITMXshadowSensors.pdfITMYshadowSensors.pdf 
  15052   Wed Nov 27 13:14:02 2019 ranaUpdateLSCITMX and ITMY OSEMs with low and high circulating powerif the RP don't fit

u must acquit

sweep the laser amplitude
  
  15053   Wed Nov 27 16:10:29 2019 gautamUpdateLSCAOM reconnectedi reconnected the AOM driver to the AOM
in the main beam path (it was hijacked for
the AOM in the AUX laser path for Anjali's
  
  15056   Wed Nov 27 23:24:01 2019 gautamUpdateLSCNo shaking but no inspiration eitherSummary:

I tried the following minor changes
to the locking procedure to see if there
  
  15057   Sun Dec 1 13:38:48 2019 ranaUpdateLSCNo shaking but no inspiration eitheryes, reasonable   
  15062   Tue Dec 3 00:03:57 2019 gautamUpdateLSCGreen ALS also shows elevated noise with high arm buildupSummary:  ALSnoiseIncrease_greenBeat.pdf 
  15073   Wed Dec 4 19:54:27 2019 gautamUpdateLSCA look to the pastTrawling
through some past elogs, I saw that the ALS
noise increase as a function of CARM offset
 DRFPMI_2016March.pdf 
  15075   Thu Dec 5 01:54:39 2019 gautamUpdateLSCPartial CM board path engaged
The arm powers could be stabilized
somewhat once the CM_SLOW path to MC2 was
engaged.
However, I was never
 AOengaged.pdf 
  15080   Fri Dec 6 00:02:48 2019 gautamUpdateLSCWhat is the correct way to set the 3f offsets?Summary:

I made it to 0 CARM offset, PRMI
locked a bunch of times today. However, I
  
  15081   Fri Dec 6 15:22:01 2019 gautamFrogsLSCDAFI system revived[Jordan, gautam]

We did the following:
  
  15172   Wed Jan 29 00:29:43 2020 gautamUpdateLSClocking 2020The goal tonight was to go through the
locking scripts to see if I could recover
the state from November 2019, when I could
 PRFPMI_2020Jan.png 
  15185   Tue Feb 4 02:13:02 2020 gautamUpdateLSCLocking updatesSummary:

The CARM-->RF transition remains
out of reach. No systematic diagnosis scheme
 modifiedOutMat.pngOLTFs.pdf 
  15188   Wed Feb 5 16:35:12 2020 gautamUpdateLSCDiagnosis planThe goal is to try and identify the source
of the excess ALS noise as the CARM offset
is reduced. The idea is to look at the MC_F
 ALSnoise.pdf 
  15191   Thu Feb 6 01:16:58 2020 gautamUpdateLSCDiagnosis resultsSummary:

I did some more detailed tests
to see if I could isolate where the excess
 IMCspec_ALS.pdfIMCspec_ALS_smallSpan.pdf 
  15192   Thu Feb 6 01:25:50 2020 gautamUpdateLSCLocking updatesSummary:

I managed to partially stabilize
the arm citculating powers - they stay in
 semiStableArms.pngarmAngStability.png 
  15195   Fri Feb 7 02:24:24 2020 gautamUpdateLSCSome short notes[koji, gautam] 

Plots + interpretation tomorrow.


CM_Slow path can be used
  
  15199   Fri Feb 7 15:00:16 2020 gautamUpdateLSCMore high BW POY experimentsTo study the evilution of the AO path TFs
a bit more, I've hooked up POY11_Q Mon
to IN1 of the CM board. I will revert the
 AO_TFs.pdf 
  15200   Fri Feb 7 19:39:10 2020 KojiUpdateLSCMore high BW POY experimentsThis measurement tells you how the gain
balance between the SLOW_CM and AO paths
should be. Basically, what you need is to
  
  15208   Wed Feb 12 12:13:37 2020 gautamUpdateLSCAO path attemptsSummary:


​The
PRFPMI can be controlled by a mix of ALS
 CARM_OLTF.pdfPRFPMI_errSigs.pdf 
  15210   Thu Feb 13 02:07:26 2020 gautamUpdateLSCAO path transfer function measurementSummary:

I measured the transfer function
of the AO path, and think that there are
 AOpathTF.pdfIMCinLoop.pdf 
  15232   Thu Feb 27 17:59:02 2020 gautamUpdateLSCSome AO thoughtsWhile my checks of the AO signal path have
thrown up some unanswered questions, I don't
think there's any evidence in those measurements
  
  15245   Tue Mar 3 19:11:48 2020 gautamUpdateLSCSome locking prep
Re-aligned and locked the arm cavities
for IR and green.
Re-set trans
normalization because after the c1iscex
  
  15268   Thu Mar 12 01:33:21 2020 gautamUpdateLSCResuming locking activitiesIt's been a while since I've attempted
any locking, so tonight was mostly getting
the various subsystems back together.
 ExcessFreqNoise_LSC.pdf 
  15273   Fri Mar 13 00:32:38 2020 gautamUpdateLSCSome progressFinally, some RF only CARM, see Attachment
#1. During this time,
 RFonly_CARM.pngCARMTF.pdf 
  15278   Tue Mar 17 01:22:03 2020 gautamUpdateLSCLocking updatesSummary:

No real progress tonight - I made
it a bunch of times to the point where CARM
  
  15281   Thu Mar 19 03:33:28 2020 gautamUpdateLSCMore locking updatesSome short notes, more details tomorrow.


I was able to make it to
CARM on RF only ~10 times tonight.
Highest
 PRFPMI_lock.pngCARMTF.pdfDARM_AvB.pdflockLoss.png 
  15324   Mon May 11 00:12:34 2020 gautamUpdateLSCRF only PRFPMIFinally - Attachment
#1. This plot uses
 PRFPMIlock.pdfIMG_8549.JPGIMG_8548.JPGDARM_OLTF.pdf 
  15326   Tue May 12 18:16:17 2020 gautamUpdateLSCRelative importance of losses in the arm and PRCAttachment
#1 is meant to show
 armLossVSPRCloss.pdf 
  15327   Tue May 12 20:16:31 2020 KojiUpdateLSCRelative importance of losses in the arm and PRCIs \eta_A the roundtrip loss for an arm?

Thinking about the PRG=10 you saw:
- What's the current PR2/3 AR?
  
  15328   Tue May 12 22:47:49 2020 gautamUpdateLSCRelative importance of losses in the arm and PRCYes, \eta_A is the (average) round-trip
loss for an arm cavity. I'd estimate
this is ~100ppm currently. I edited the original
  
  15330   Thu May 14 00:21:03 2020 gautamUpdateLSCCM board boostsSummary:

I think the boosts that are currently
stuffed on the CM board are too
 boosts.pdfboosts_noise.pdf 
  15348   Tue May 26 02:15:36 2020 gautamUpdateLSCLock acquisition portal entrySummary:

Provided the IMC
is cooperative, the input pointing isn't
  
  15349   Tue May 26 02:31:00 2020 gautamUpdateLSCLock acquisition sequenceHere, I provide some details of the sequence.
Obviously, I am presenting one of the quickest
transitions to the fully locked state, I
 PRFPMIlock_1274418200_1274418550.pdf 
  15350   Tue May 26 02:37:19 2020 gautamUpdateLSCDARM loop measurement and fittingSummary:

In order to estimate the free-running
DARM displacement noise, I measured the DARM
 DARM_TF.pdfDARM_TF_breakdown.pdf 
  15351   Tue May 26 03:01:35 2020 gautamUpdateLSCCARM loop Summary:

I am able to realize ~8
kHz UGF with ~60 degrees
 CARM_OLTF.pdf 
  15352   Tue May 26 03:06:59 2020 gautamUpdateLSCPRFPMI sensing matrixSummary:

The response of the PRFPMI length
degrees of freedom as measured in the LSC
 PRFPMI_20200524sensMat.pdfPRFPMI_20200524sensMatHistograms.pdf 
  15353   Tue May 26 03:26:58 2020 gautamUpdateLSCPreliminary noise budgetSummary:

This isn't meant to be a serious
budget, mainly it was to force myself to
 PRFPMI_NB.pdf 
  15355   Tue May 26 14:32:44 2020 gautamUpdateLSCArm transmission RINSummary:

The measured RIN of the arm cavity
transmission when the PRFPMI is locked is
 armRIN.pdf 
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