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Entry  Sat May 9 17:01:08 2020, Yehonathan, Update, Loss Measurement, 40m Phase maps loss estimation ITMX_Loss_Map.pdfETMX_Loss_Map.pdfITMX_Phase_Map_(nm).pdfETMX_Phase_Map_(nm).pdf
    Reply  Wed May 13 15:13:11 2020, Yehonathan, Update, Loss Measurement, 40m Phase maps loss estimation ITMX_Loss_Map.pdfETMX_Loss_Map.pdf
       Reply  Thu May 14 12:21:56 2020, Yehonathan, Update, Loss Measurement, 40m Phase maps loss estimation ITMX_Loss_Map_Perturbation_Theory.pdfETMX_Loss_Map_Perturbation_Theory(1).pdf
          Reply  Thu May 14 19:00:43 2020, Yehonathan, Update, Loss Measurement, 40m Phase maps loss estimation 
             Reply  Tue May 19 15:39:04 2020, Yehonathan, Update, Loss Measurement, 40m Phase maps loss estimation Mode_power_fraction1.pdf
Message ID: 15329     Entry time: Wed May 13 15:13:11 2020     In reply to: 15323     Reply to this: 15332
Author: Yehonathan 
Type: Update 
Category: Loss Measurement 
Subject: 40m Phase maps loss estimation 

Koji pointed out during the group meeting that I should compensate for local tilt when I move the beam around the mirror for calculating the loss map.

So I did.

Also, I made a mistake earlier by calculating the loss map for a much bigger (X7) area than what I thought.

Both these mistakes made it seem like the loss is very inhomogeneous across the mirror.

Attachment 1 and 2 show the corrected loss maps for ITMX and ETMX respectively.

The loss now seems much more reasonable and homogeneous and the average total arm loss sums up to ~ 22ppm which is consistent with the after-cleaning arm loss measurements.

Attachment 1: ITMX_Loss_Map.pdf  20 kB  Uploaded Wed May 13 16:24:34 2020  | Hide | Hide all
ITMX_Loss_Map.pdf
Attachment 2: ETMX_Loss_Map.pdf  20 kB  Uploaded Wed May 13 16:24:45 2020  | Hide | Hide all
ETMX_Loss_Map.pdf
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