Ignore:
Timestamp:
Jul 17, 2018 1:58:12 PM (4 years ago)
Author:
srkline
Message:

two significant changes:

1- in the averaging, before the data is finally written out, duplicate q-values (within 0.1%) are averaged so that duplicate q-values do not appear in the data file. This has a very bad effect on the calculation of the smearing matrix (dq=0).

2-for the data from the back (high res) detector, two steps have been added to the processing at the point where the data is converted to WORK. First, a constant read noise value of 200 cts/pixel is subtracted (found from average of multiple runs with beam off) Second, a 3x3 median filter is applied to the whole image to eliminate the stray bright pixels. Some are saturatd, some are simply outliers. Very effective.

File:
1 edited

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  • sans/Dev/trunk/NCNR_User_Procedures/Reduction/VSANS/V_Initialize.ipf

    r1109 r1111  
    7575Strconstant ksBinTrimBegDefault = "B=5;FT=3;FB=3;FL=3;FR=3;MT=3;MB=3;ML=3;MR=3;FTB=2;FLR=2;MTB=2;MLR=2;FLRTB=1;MLRTB=1;" 
    7676Strconstant ksBinTrimEndDefault = "B=10;FT=5;FB=5;FL=5;FR=5;MT=5;MB=5;ML=5;MR=5;FTB=4;FLR=4;MTB=4;MLR=4;FLRTB=3;MLRTB=3;" 
     77 
     78// the average read noise level of the back detector 
     79// taken from multiple runs with the beam off, 6-28-18 
     80// runs sans12324 - sans12353 
     81// 
     82// used in V_Raw_to_Work() 
     83// average of whole panel (tested several data files) = 208 +/- 14 
     84// 
     85// 200 appears to be a better value - (empirical, based on teflon/converging pinhole data) 
     86Constant kReadNoiseLevel = 200 
     87//Constant kReadNoiseLevel = 208 
     88Constant kReadNoiseLevel_Err = 14 
     89 
     90 
     91 
     92// Pixel shifts for the back detector to bring the three CCDs into registry 
     93// data from pinholes used to match up CCDs 
     94// 27 JUN 2018 
     95// runs 12221,12225,27,33,34,35,38,42 
     96// middle CCD is not moved 
     97// See V_ShiftBackDetImage() for implementation 
     98Constant        kShift_TopX = 7 
     99Constant                kShift_TopY = 105 
     100Constant                kShift_BottomX = 5 
     101Constant                kShift_BottomY = 35 
     102 
     103 
    77104 
    78105 
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