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Entry  Mon Mar 26 23:47:54 2012, Suresh, Update, IOO, Beam Profile measurement: IPPOS beam BeamProfile_IPPOS.pngBeamProfile_IPPOS.pdfBeamProfileData_IPPOS.xlsx
    Reply  Tue Mar 27 02:05:40 2012, Suresh, Update, IOO, Beam Profile measurement: IPPOS beam BeamProfile_IPPOS.pngBeamProfile_IPPOS.png
       Reply  Tue Mar 27 11:54:18 2012, Jenne, Update, IOO, Beam Profile measurement: IPPOS beam IPPOS_distances.pdf
          Reply  Tue Mar 27 18:03:46 2012, Jenne, Update, IOO, Beam Profile measurement: IPPOS beam BeamProp_usingMeas2012MMTnumbersLowRes.png
             Reply  Tue Mar 27 21:20:32 2012, Jenne, Update, IOO, Beam Profile measurement: IPPOS beam BeamProp_usingMeas2012MMTnumbersLowRes.png
                Reply  Tue Mar 27 23:37:35 2012, Suresh, Update, IOO, Beam Profile measurement: IPPOS beam Beam-Profile_IPPOS_wError.png
                Reply  Wed Mar 28 01:17:29 2012, Jenne, Update, IOO, Beam Profile measurement: IPPOS beam BetterDistances_IPPOSLowRes.pngBetterDistances_MainIFO_PRMnormalLowRes.pngBetterDistances_MainIFO_PRMflippedLowRes.png
                   Reply  Wed Mar 28 18:26:47 2012, Jenne, Update, IOO, Beam Profile measurement: IPPOS beam OptimizedMMT_halfMeterChange_IPPOSviewLowRes.pngOptimizedMMT_halfMeterChange_IFOviewLowRes.pngOptimizedMMT_pt2cMeterChange_IPPOSviewLowRes.pngOptimizedMMT_pt2cMeterChange_IFOviewLowRes.png
                      Reply  Wed Mar 28 20:54:02 2012, Jenne, Update, IOO, Beam Profile measurement: IPPOS beam MMT_moved_by_1pt3meters_MMT1th_25_MMT2th_12_LowRes.pngMMT_moved_by_1pt3meters_MMT1th_25_MMT2th_12_LowRes.png
                         Reply  Mon Apr 2 18:58:32 2012, Jenne, Update, IOO, Beam Profile measurement: IPPOS beam NonOptimized_propagatedWaistPlotted_LowRes.png
                         Reply  Mon Apr 2 23:06:38 2012, Suresh, Update, IOO, Beam Profile measurement: IPPOS beam: Mystery deepens 40mOpticsLocations.pdfBeam-Profile_IPPOS_wError.pdfBeam-Profile_PRM_1_wError.pdf
       Reply  Tue Mar 27 17:19:02 2012, Koji, Update, IOO, Beam Profile measurement: IPPOS beam 
    Reply  Tue Mar 27 02:18:31 2012, keiko, Update, IOO, Beam Profile measurement: IPPOS beam text9149.pngfirst_cap.pngsecond_cap.pngtext9149.png
       Reply  Tue Mar 27 16:06:59 2012, keiko, Update, IOO, Beam Profile measurement: IPPOS beam 
Message ID: 6449     Entry time: Tue Mar 27 02:18:31 2012     In reply to: 6447     Reply to this: 6452
Author: keiko 
Type: Update 
Category: IOO 
Subject: Beam Profile measurement: IPPOS beam 

Keiko, Rana, Suresh

Related to the beam profile of IPPOS today, we tried to measure the beam size at the ETMY point in order to estimate the input beam mode. We measured the beam size hitting at the suspension frame by a camera image, with two situations to see two "z" for beam profile.

(1) Input beam is slightly misaligned and the injected beam hits the end mirror frame. Assuming z=0 at the input mirror, this should be z=40m.

(2) Input beam hits the centre of the end mirror, and ITMY is slightly misaligned and the beam hits the end mirror frame after the one-round trip. Assuming z=0 at the ITM, this position should be z=120m.

text9149.png

The injected beam at the end point and the one round trip ligt at the end point should be the same size, if the input mode matches to the cavity mode. You can see if your injected light is good for the cavity or not. We compared and assumed the above two beam sizes by looking at the photo of the beam spot.

(1) first_cap.png (2) second_cap.png

 Assuming the zoom factor difference by the part below the beam (shown with allow in the photos. Arbitrary unit.), the beam in (2) is smaller than expected (roughly 40%?).

However this is a very rough estimation of the beam sizes! It is difficult to assume the beam size shown on the photos! It looks smaller only because the power of (2) is smaller than of (1). I don't think we can say anything from this rough estimation. One may be able to estimate better with CCD camera instead of this normal camera. 

 

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