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Entry  Mon Sep 11 23:31:50 2017, johannes, Update, Cameras, post-vent camera capture comparison 13x
    Reply  Tue Sep 26 22:11:08 2017, johannes, Update, Cameras, post-vent camera capture comparison lens_distance.pdfImage__2017-09-26__18-54-29.jpgIMG_20170926_190157222_HDR.jpgIMG_20170926_185649325.jpg
       Reply  Mon Oct 2 12:44:45 2017, johannes, Update, Cameras, Basler 120gm calibration calib_20170930_152.pdfcalib_20170930_153.pdf
          Reply  Mon Oct 2 23:16:05 2017, gautam, HowTo, Cameras, CCD calibration 
             Reply  Tue Oct 3 01:58:32 2017, johannes, HowTo, Cameras, CCD calibration gige_calibration.pdf
                Reply  Thu Oct 12 01:03:49 2017, johannes, HowTo, Cameras, ETMX GigE side view IMG_20171011_164549698.jpgImage__2017-10-11__16-52-01.pngGigE_lens_position_helper.py.zip
                   Reply  Thu Oct 12 07:56:33 2017, Steve, HowTo, Cameras, ETMX GigE side view at 50 deg of IR scattering Image__2017-10-11__15-29-52_15k400g.pngImage__2017-10-12__15-50-18wipedRefocud2.pngcamCan16cm.jpg
                      Reply  Wed Oct 18 11:37:58 2017, johannes, HowTo, Cameras, ETMX GigE side view at 50 deg 
                Reply  Wed Oct 18 15:26:58 2017, johannes, HowTo, Cameras, Revision: CCD calibration calib_20170930_152.pdfcalib_20170930_153.pdf
Message ID: 13391     Entry time: Wed Oct 18 15:26:58 2017     In reply to: 13354
Author: johannes 
Type: HowTo 
Category: Cameras 
Subject: Revision: CCD calibration 

The units were still off in my previous post. Here's the corrected, sanity-checked version:

Camera IP Calibration Factor 85.8 +/- 4.3 pW*μs 78.3 +/- 3.9 pW*μs

I estimated the uncertainties based on a linear fit to the data I recorded with 75nW incident on the CCD and assumed a 5% uncertainty in that number. This is just an upper limit, to be safe. I had calibrated the power reading placing the Ophir power meter where the CCD would otherwise be and comparing it to the PD voltage of a picked off beam. In my previous figures the axes were mislabeled, so I reproduce them here:

Using the current camera position I recorded 50 exposures both with and without beam (XARM locked vs PSL shutter closed) and averaged the images to see how much the reading fluctuates. The exposure time was 10 ms, which left the maximum reported pixel value in all exposures below 3800 out of 4096. The gain setting was 100, which is what I used to calibrate the CCDs.

Counts with XARM locked 2.799 +/- 0.027 x107
Counts with shutter closed 3.220 +/- 0.047 x106
Power on CCD 193.9 +/- 2.2 nW
Power scattered into 2π (*) 254 +/- 39 μW
ETMX scatter loss (**) 25.4 +/- 3.9 ppm

(*) I calculated the lens positions to focus at a plane 65cm from the front lens. We're pretty close to that, but I can't confirm the actual distance easily, so I assumed a 5cm error on the distance, which is where most of the error is coming from. This is also assuming uniform scatter.

(**) This is assuming 10W of circulating power

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