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Entry  Sat Dec 8 04:12:38 2012, Den, Update, LSC, prcl IMG_0118.JPG
    Reply  Sun Dec 9 01:21:51 2012, Den, Update, LSC, beam inside DRMI is clipping on PR3 Tip-Tilt 6x
       Reply  Sun Dec 9 17:51:53 2012, rana, Update, LSC, beam inside DRMI is clipping on PR3 Tip-Tilt 
          Reply  Mon Dec 10 03:02:03 2012, Den, Update, LSC, beam inside DRMI is clipping on PR3 Tip-Tilt PRCL_LOCK.png
             Reply  Mon Dec 10 10:13:41 2012, Den, Update, LSC, beam inside DRMI is clipping on PR3 Tip-Tilt 
                Reply  Mon Dec 10 22:34:34 2012, Den, Update, LSC, beam inside DRMI is clipping on PR3 Tip-Tilt PR2.bmpPRM_LOCK.bmpITMY.pngITMX.png
                   Reply  Thu Dec 13 03:20:48 2012, Den, Update, LSC, beam inside DRMI is clipping on PR3 Tip-Tilt PR2_ITMX.pngPR2_ITMY.pngPR3_LOCK.png
Message ID: 7820     Entry time: Thu Dec 13 03:20:48 2012     In reply to: 7806
Author: Den 
Type: Update 
Category: LSC 
Subject: beam inside DRMI is clipping on PR3 Tip-Tilt 

Quote:

 

 I've made snapshots of PR2, PRM, ITMY and ITMX mirrors. Power buildup recycling gain (POWER BS / POWER PRM) was equal to 3-4.

           

 We've looked at PR2 face camera when PRM, BS and one of the ITMs were aligned. We saw an extra beam at PR2 when ITMX was aligned (right plot). This spot stays on the PR2 when prcl is locked.

PR2_ITMX.png   PR2_ITMY.png

Then we looked at PR3 transmission mirror and saw that the main beam is not on the edge of the mirror. Secondary beam is clipping on the mirror mount of PR3 that we see on BS_PRM camera.

PR3_LOCK.png

Measured beam spot positions:

Optics Pitch, mm Yaw, mm
ITMX 5.6 1.5
ETMX -1.5 1.5
ITMY 4.8 -1.5
ETMY -1.4 5.6
PRM 2.7 4.1

"+" for pitch means that the beam is too high, "-" too low

"+" for yaw means that the beam is left if you look from the back, "-" is right

Beam spots were measured using x, y arm and prcl locking to the carrier.

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