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ID Date Author Type Category Subjectdown Text Attachments
  9213   Mon Oct 7 13:55:26 2013 JenneUpdateLSCArms locked in IR for many hoursSomeone left the arms aligned, and the
LSC engaged, so the arms have been locked
almost continuously for several days
 BothArmsLocked3Days_7Oct2013.png 
  2605   Tue Feb 16 10:01:16 2010 AlbertoConfigurationLSCArms and PRC not lockingSince last Friday either the arms or the
PRC can't lock.
The montors show the beam flashing
  
  2607   Tue Feb 16 14:10:06 2010 josephb, rob, kojiConfigurationLSCArms and PRC not locking

    
        
  
  2608   Tue Feb 16 15:25:00 2010 AlbertoConfigurationLSCArms and PRC not locking 
 
 shock.jpg 
  10558   Wed Oct 1 19:40:46 2014 ericqUpdateLSCArms IR alignedSummary:

    Beamsplitter
was put into MC refl path.
    HWP
was rotated to maximize power into PMC. 
  
  15225   Wed Feb 26 17:17:17 2020 YehonathanUpdate Arms DC loss measurements{Yehonathan, Gautam}

In order to measure the loss in
the arm cavities in reflection, we use the
 6x 
  2611   Wed Feb 17 19:36:05 2010 KojiUpdateCOCArm visibilityI
have measured the arm visibilities.
I did not see any change since the
  
  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 
  15359   Wed May 27 19:36:33 2020 KojiUpdateLSCArm transmission RINMy speculation for the worse RIN is:

- Unoptimized alignment -> Larger
linear coupling of the RIN with the misalignment
  
  15361   Thu May 28 18:36:45 2020 gautamUpdateLSCArm transmission RINI agree, I think the PRC excess angular
motion, PIT
in particular, is a dominant
 PRFPMIcorner_ASC_PIT_1274419354_1274419654.pdfPRFPMIcorner_ASC_YAW_1274419354_1274419654.pdfPRFPMIcorner_ASC_coherence_1274419354_1274419654.pdf 
  15362   Fri May 29 00:34:57 2020 ranaUpdateLSCArm transmission RINhow bout corner plot with power signals
and oplevs? I think that would show not just
linear couplings (like your coherence), but
  
  15264   Tue Mar 10 19:59:09 2020 YehonathanUpdateLoss MeasurementArm transfer function measurementI want to measure the transfer function
of the arm cavities to extract the pole frequencies
and get more insight into what is going
 YArmFrequencyResponse.pdf 
  15269   Thu Mar 12 10:43:50 2020 ranaUpdateLoss MeasurementArm transfer function measurement 
           
  
  15277   Mon Mar 16 15:23:03 2020 YehonathanUpdateLoss MeasurementArm transfer function measurementI measured the cross-calibration of the
two PDs on the PSL table.

I used the existing flip mounted
 Cross_calibration_setup.jpgPDA520overPDA255_Response.pdfYArmFrequencyResponse.pdf 
  15307   Sat Apr 18 14:57:44 2020 YehonathanUpdateLoss MeasurementArm transfer function measurementOk, now I understand my foolishness. It
should definitely be 1/sqrt(f^2+fp^2)
.
  
  10248   Mon Jul 21 17:32:43 2014 ericqSummaryLSCArm losses

    

       
            
  
  12533   Wed Oct 5 19:10:04 2016 gautamUpdateGeneralArm loss measurement review[ericq,gautam]

There are multiple methods by which
the arm loss can be measured, including,
  
  1576   Tue May 12 01:22:51 2009 YoichiUpdateLSCArm lossUsing the armLoss script (/cvs/cds/caltech/scripts/LSC/armLoss),
I measured the round trip loss (RTL) of the
arms.
  
  11524   Sat Aug 22 15:48:32 2015 KojiSummaryLSCArm locking recoveryAs per Ignacio's request, I restored
the arm locking.

- MC WFS relief
  
  3001   Thu May 27 12:52:02 2010 AlbertoUpdate40m UpgradingArm lengths
For both sidebands to be antiresonant
in the arms, the first modulation frequency
  
  11098   Wed Mar 4 19:03:19 2015 ericqUpdateLSCArm length remeasurementAs discussed at today's meeting, we
would like to (re)measure the Arm cavity
lengths to ~mm precision, and their g-factors.
 Xscan.pngYscan.png 
  11107   Fri Mar 6 02:10:35 2015 ranaUpdateLSCArm length remeasurementThis has been done before:

http://nodus.ligo.caltech.edu:8080/40m/6938

Arm length measurements and g-factor
  
  5079   Mon Aug 1 04:08:24 2011 kiwamuUpdateABSLArm length measurement : cavity kick techniqueI made some
attempts to measure the current length of
 ETMY_kick.png 
  5095   Tue Aug 2 16:55:21 2011 ranaUpdateABSLArm length measurement : cavity kick technique

    

       
            
 L.png 
  14944   Sun Oct 6 15:23:27 2019 gautamUpdateALSArm control using error signals achievedSummary:

I
 ALSY_20191006.pdftransitionIRALS.pngarms_ALS.pdf 
  8844   Sun Jul 14 18:19:00 2013 AnnalisaUpdateGreen LockingArm cavity scanYesterday evening Nic and me were in the
lab. The Mode Cleaner was unlocked, but after
many attempt we could fix it and we did many
  
  15860   Wed Mar 3 23:23:58 2021 gautamUpdateALSArm cavity scanI see no evidence of anything radically
different from my PSL table optical
characterization in the IMC transmitted
 armScan.pdf 
  2416   Mon Dec 14 22:32:56 2009 KojiUpdateGeneralArm cavity loss ~ resultI like to ask someone to review the calculation
on the wiki.
  
  2070   Thu Oct 8 20:18:56 2009 KojiSummaryGeneralArm cavity lossLast night (Oct 07), I ran armLoss script
in order to obtain the latest numbers for
the arm cavity loss.
  
  2996   Wed May 26 22:22:03 2010 AlbertoConfiguration40m UpgradingArm cavity lengthThe second sideband is resonant in the
arms for a cavity length of 37.9299m.
The nearest antiresonant arm lengths
 reflRFpowerVsArmLength_3658m.pngreflRFpowerVsArmLength_3750m.png 
  728   Wed Jul 23 22:34:07 2008 YoichiUpdateLSCArm cavity g-factor measurementI tried the same thing as the X-arm to the
Y-arm.
I'm puzzled. I found exactly the same behavior
  
  730   Thu Jul 24 01:27:00 2008 KojiUpdateLSCArm cavity g-factor measurement[quote]I locked the Y-arm and mis-aligned
the end mirror in Yaw until the transmission
power gets half.
  
  731   Thu Jul 24 02:57:26 2008 robUpdateLSCArm cavity g-factor measurement[quote]
So, now I feel that the method for the TEM01
quest should be reconsidered.
  
  733   Thu Jul 24 08:09:26 2008 YoichiUpdateLSCArm cavity g-factor measurement[quote]
A-ha! Do you always expect the 30Hz signal,
don't you?
  
  5653   Tue Oct 11 21:23:51 2011 JenneUpdateLSCArm absl lengths

    

       
            
  
  5626   Thu Oct 6 15:40:57 2011 JenneUpdateLSCArm absl length data taken[Katrin, Jenne]
We took the data for the new absolute
length measurement of both arms, after the
  
  10414   Wed Aug 20 15:31:27 2014 ericqUpdateCOCArm Loss Investigations Continue [ericq, Gabriele] 
Summary: After today's meeting, Gabriele
and I looked into the arm loss situation,
  
  2247   Thu Nov 12 02:02:18 2009 ranaSummaryLSCArm Locking with no feedback to the ETM or ITMSteps:
1) Turn off feedback to ETMY (the
ETMY button on the LSC screen).
 nohands-2.pdf 
  1456   Mon Apr 6 21:50:43 2009 ranaUpdateLSCArm Locking via pushing MC2Inspired by our 'No Refcav' scheme here, I
was inspired to re-explore the idea of locking
the
 mc2-xarm.pdfUntitled.pngnohands.pdf 
  11430   Mon Jul 20 11:57:17 2015 ericqUpdateGeneralArm Locking recoveredThe interferometer is warming up!

I had some issues locking the IMC
at first. It turned out that the MC3 side
  
  1577   Tue May 12 15:22:09 2009 YoichiUpdateLSCArm Finesse[quote]
It looks as if the measured DARM response
is skewed by an extra low pass filter at
  
  8741   Tue Jun 25 00:28:52 2013 rana, manasaUpdateLSCArm Cavity scan with X-ALS after ALS servo upgrade[Rana, Manasa]
ALS noise suppressed to 
 6x 
  8742   Tue Jun 25 10:18:34 2013 Mystery ManUpdateLSCArm Cavity scan with X-ALS after ALS servo upgrade

    

       
            
  
  8744   Tue Jun 25 11:39:13 2013 KojiUpdateLSCArm Cavity scan with X-ALS after ALS servo upgradeMy understanding is that that number is
an in-loop evaluation of the loop so far
(as the first step of the loop evaluation).
  
  2415   Mon Dec 14 19:33:04 2009 AlbertoUpdateGeneralArm Cavity Poles measured again after cleaning the optics last weekLast week we vented and we cleaned the
main optics of the arm cavities.
I measured the frequency of the cavity
 XarmTF01_fit.pdfYarmTF01_fit.pdfArmCavityFinesseMeasurment.tar.gz 
  2418   Tue Dec 15 05:29:31 2009 AlbertoUpdateGeneralArm Cavity Poles measured again after cleaning the optics last week 
 The Y arm cavity pole moved
down by 130 Hz, whereas the X arm moved by
  
  555   Mon Jun 23 21:51:19 2008 AlbertoUpdateGeneralArm Cavity Length MeasurementWe measured the arm cavity lengths sweeping
the ETM mirror position and looking at the
reflected demodulated output. We excited
 40mLengthMeasure.pdf 
  469   Thu May 8 01:50:25 2008 ranaSummaryASCArm Cavity HOM ResonancesNothing new, but I calculated the frequencies
of the first 22 higher order transverse modes
and thought I might as well list them here.
  
  2174   Wed Nov 4 16:49:32 2009 AlbertoUpdateLSCArm Cavity Finesse MeasurementI'm going to work on the X arm to measure
the arm cavity finesse.
The idea is to measure the cavity
 DSC_0952.JPG 
  2175   Wed Nov 4 18:35:19 2009 AlbertoUpdateLSCArm Cavity Finesse Measurement

    
        
  
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