Page History

...

Common mode correction is applied in the Detector interface method calib described in AreaDetector:<PATH>

arr = det.calib(evt, cmpars=None)

...

Each algorithm may load file with parameters from calibration directory, which by default accounts for experimnet, calibration version, data source, calibration type and run range, for example

/reg/d/psdm/<PATH>/<INS>/<experiment>/calib/<calib-version>/<data-source>/<calibration-type>/<run-range>.data

For example: 
<PATH>/reg/d/psdm/XPP/xppi0614/calib/Epix100a::CalibV1/NoDetector.0:Epix100a.0/pedestals/0-end.data
<PATH>/reg/d/psdm/XPP/xppi0614/calib/Epix100a::CalibV1/NoDetector.0:Epix100a.0/common_mode/0-end.data

...

• par[0] - algorithm #
• par[1] - maximal threshold on intensity to evaluate mean for low intensities
• par[2] - maximal allowed common mode correction

• par[3] - length of consecutive pixel array for common mode evaluation
  For example, for pnCCD one can evaluate common-mode for one came chip (128 channels).

  Control file:  

<PATH>/reg/d/psdm/amo/<exp-name>/calib/PNCCD::CalibV1/Camp.0:pnCCD.0/calib/PNCCD::CalibV1/Camp.0:pnCCD.0/common_mode/0-end.data

2 1000 1000 128

• The algorithm loops over the data and evaluates consecutive arrays of specified length (which might represent for example a row of pixels in a readout chip) and finds the mean value for values below a threshold, ignoring masked pixels.  It corrects all the data if the calculated common mode is less than the maximal allowed correction.  The median algorithm is more stable in many cases and is recommended.

...

• AreaDetector - Detector Interface is described in the head of this file.
• 2014-03-25-Ankush-CommonModeNoise.pdf - stand-alone test of common mode correction for pnCCD
• psana - Module Catalog - Module ImgAlgos::NDArrCalib
• Epix100a
• Fccd960-Detector
• numpy.median
• <PATH>