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Entry  Tue Apr 24 11:31:59 2018, gautam, Configuration, ALS, Proposed changes to EX fiber coupling EX_fiber_MM.pdfEX_fiber_changes.png
    Reply  Tue Apr 24 18:54:15 2018, gautam, Configuration, ALS, Proposed changes to EX fiber coupling 
       Reply  Wed Apr 25 19:09:37 2018, gautam, Configuration, ALS, New look EX Fiber coupling EX_fiber_MM.pdfIMG_6977.JPGIMG_6972.JPGIMG_6974.JPGIMG_6976.JPG
          Reply  Thu Apr 26 11:24:50 2018, gautam, Configuration, ALS, New look EX Fiber coupling - pol stability polStab.pdf
             Reply  Thu Apr 26 18:58:21 2018, Bruce, Configuration, ALS, New look EX Fiber coupling - pol stability 
             Reply  Fri Apr 27 01:36:02 2018, gautam, Configuration, ALS, IR ALS noise performance 2018_04_BeatMouth_POX.pdf2018_04_BeatMouth.pdfALSSpecgram.pdfALS_ASD.pdfALSstab.pdf
                Reply  Wed May 2 21:39:33 2018, gautam, Configuration, ALS, IR ALS for EY 
                   Reply  Fri May 4 21:17:57 2018, gautam, Configuration, ALS, BeathMouth pulled out of PSL table 
                      Reply  Tue May 8 00:40:51 2018, gautam, Configuration, ALS, BeathMouth pulled out of PSL table IMG_6986.JPGIMG_6987.JPG
                         Reply  Thu May 24 19:41:28 2018, gautam, Configuration, ALS, BeathMouth reinstalled on PSL table 
                      Reply  Thu May 24 13:06:17 2018, gautam, Configuration, ALS, DFD noises DFDcalib.pdfDFD_NB.pdf
                         Reply  Thu May 24 20:31:03 2018, gautam, Configuration, ALS, DFD noises TF_X_mag.pdfTF_X_phase.pdf
Message ID: 13791     Entry time: Thu Apr 26 11:24:50 2018     In reply to: 13789     Reply to this: 13792   13796
Author: gautam 
Type: Configuration 
Category: ALS 
Subject: New look EX Fiber coupling - pol stability 

Here is a first look at the overnight stability. For the temperature, I used the calibration I found in the old psl database file, seems to give sensible results. It's only 15 hours of data plotted, so we don't see the full 24 hour temperature swing, but I think it is safe to say that for the EX fiber, the dominant cause of the "waveplate effect" is not in fact temperature drift. The polarization extinction is still better than 10dB in the entire period of observation though... I'm going to push ahead with a beat spectrum measurement, though there is room for improvement in the input coupling alignment to fiber special axes.

The apparent increase in these plots towards the end of the 15 hour period is because the lights on the PSL table were switched on.


Annoyingly, it seems like the PSL NPRO channels (which I have hijacked to do this test) do not have minute trend data directly accessible from NDS2. Not sure whether this is an NDS2 problem, or something missing in the way the channels are setup with Acromag. Probably the former, as I am able to generate minute trend plots with dataviewer. I forget whether this is the same as the infamous minute trend problem. Second trend data is available though, and is what I used to make these plots...

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