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Entry  Wed Nov 25 16:40:32 2015, yutaro, Update, LSC, round trip loss of Y arm 
    Reply  Wed Nov 25 23:34:52 2015, yutaro, Update, LSC, round trip loss of Y arm 14.png
       Reply  Fri Nov 27 03:38:23 2015, yutaro, Summary, LSC, round trip loss of Y arm image1.png
          Reply  Fri Nov 27 22:20:24 2015, yutaro, Update, LSC, round trip loss of Y arm log.txt.zip17.png
          Reply  Sat Nov 28 11:46:40 2015, yutaro, Update, LSC, possible error source of loss map measurement 
          Reply  Mon Nov 30 10:41:45 2015, yutaro, Update, LSC, Does a baffle in front of ETMY have effect on loss map measurement? 
             Reply  Mon Nov 30 17:17:30 2015, yutaro, Update, LSC, Does a baffle in front of ETMY have effect on loss map measurement? element2-2.pngelement0-0.pngelement4-4.png
          Reply  Mon Dec 7 11:11:25 2015, yutaro, Summary, LSC, round trip loss of X arm image1-2.JPGsymmetry.png
Message ID: 11828     Entry time: Mon Nov 30 17:17:30 2015     In reply to: 11823
Author: yutaro 
Type: Update 
Category: LSC 
Subject: Does a baffle in front of ETMY have effect on loss map measurement? 

With captured images of ETMYF, I measured the shift of the beam spot on ETMY.

The conclusions are:

the baffle would have almost no effect on loss map measurement and

the calibration of beam spot shift is confirmed to be not so bad.

 

What I did:

I captured ETMYF images in the cases that (i)beam spot is centered on ETMY, beam spot is at the rightest and lowest point of my loss map measurement (corresponding to [0,0] component of the matrix shown in elog 11818), and beam spot is at the leftest and highest point of my loss map measurement ([4,4] component). Each captured image is attached.

Then using ImageJ, I measured the shift of the beam spot. I calibrated lengh in horizontal direction and vertical direction with the diameter of the mirror. 

Results:

The amount of the beam shift was 7.2 mm and 8.0 mm for each case.

These values indicate that clapping loss due to the baffle is less than 10 ppm in a round trip.

Today's results support the previous calibration with oplev, which says the amount of the beam shift is 7.0 mm. Two values derived by different calibrations coincide within ~10 % though they are totally different methods. This also support the calibration of the oplev for ETMY (elog 11785) indirectly. 

 

 

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