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Entry  Fri Feb 8 18:23:32 2013, Jamie, Summary, General, arbcav of half PRC with flipped PR2 prm23t-modes.pdfprm23t-geometry.pdf
    Reply  Fri Feb 8 19:29:44 2013, yuta, Summary, General, arbcav of half PRC with flipped PR2 
       Reply  Mon Feb 11 17:17:30 2013, Jamie, Summary, General, more analysis of half PRC with flipped PR2 foo.pdf
          Reply  Tue Feb 12 18:25:43 2013, Jamie, Summary, General, half PRC with astigmatic PR2/3 
Message ID: 8068     Entry time: Tue Feb 12 18:25:43 2013     In reply to: 8059
Author: Jamie 
Type: Summary 
Category: General 
Subject: half PRC with astigmatic PR2/3 

Quote:
  arbcav a la mode measurement
g tangential 0.9754 0.9753 0.986 +/- 0.001
g sagital 0.9686 0.9685 0.968 +/- 0.001

Given that we're measuring different g parameters in the tangential and sagittal planes, I went back to alamode to see what astigmatism I could put into PR2 and/or PR3 to match what we're measuring.  I looked at three cases: only PR2 is astigmatic, only PR3 is, or where we split the difference.  Since the sagittal measurement matches, I left all the sagittal curvatures the same in

case 1: PR3 only

  PR2 RoC (m) PR3 RoC (m) g (half PRC)
tangential 706 -420 0.986
sagittal 706 -700 0.969

case 2: PR3 only

  PR2 RoC (m) PR3 RoC (m) g (half PRC)
tangential 5000 -700 0.986
sagittal 706 -700 0.969

case 3: PR2 and PR3

  PR2 RoC (m) PR3 RoC (m) g parameter
tangential 2000 -600 0.986
sagittal 706 -700 0.969

From Koji's post about the scans of the G&H mirrors, it looks entirely reasonable that we could have these levels of astigmatism in the optics.

What this means for full PRC

These all make the same full PRC situation:

     g (tangential):  0.966

     g (sagittal):  0.939

     ARM mode matching:  0.988

 

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