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Entry  Tue Jun 4 00:17:15 2019, gautam, Update, BHD, Preliminary BHD calculations LOreqs.pdf
    Reply  Thu Jun 6 18:49:22 2019, gautam, Update, BHD, Preliminary BHD calculations darkPortScatter.pdfOMCbackscatter.pdfdirectScatter.pdf
       Reply  Wed Jul 3 11:47:36 2019, gautam, Update, BHD, PRC filtering PRCfiltering.pdf
          Reply  Wed Jul 31 09:41:12 2019, gautam, Update, BHD, OMC cavity geometry paramSpaceHeatMap.pdf
             Reply  Wed Jul 31 17:57:35 2019, Koji, Update, BHD, OMC cavity geometry 
             Reply  Fri Aug 23 10:01:14 2019, gautam, Update, BHD, OMC cavity geometry - some more modeling modeContentComparison.pdfOMCtransComparison.pdf
       Reply  Tue Aug 6 15:52:06 2019, gautam, Update, BHD, Preliminary BHD calculations OMCbackscatter.pdf
Message ID: 14821     Entry time: Wed Jul 31 17:57:35 2019     In reply to: 14819
Author: Koji 
Type: Update 
Category: BHD 
Subject: OMC cavity geometry 

4 deg is not an optimized number optimized for criteria, but to keep the cavity short width to 0.1m. But the justification of 4deg is found in Section 3 and 4 of T1000276 on Page 4.

Quote:

Question for Koji: how is the aLIGO OMC angle of incidence of ~4 degrees chosen? Presumably we want it to be as small as possible to minimize astigmatism, and also, we want the geometric layout on the OMC breadboard to be easy to work with, but was there a quantitative metric? Koji points out that the backscatter is also expected to get worse with smaller angles of incidence.

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