This note describes raw intensity correction algorithms in the method Detector.calib and their variation on detector type.
LCLS Detector Interface
Method calib
arr = det.calib(evt, cmpars=None, **kwargs)
Regular sequence of applied algorithms
- dark correction - pedestals subtraction using calib/.../pedestals
- common mode correction depending on cmpars or calib/.../common_mode or default from PSCalib.CalibParsBase*V1.py
- gain correction factors from calib/.../pixel_gain. Depending on detector pixel_gain calibration array may contain per-pixel gain in ADU/keV or gain correction factor gfactor in keV/ADU, where gfactor=1/gain.
- apply mask depending on **kwargs
Correction formula
(common_mode(raw - peds))/gain * mask(**kwargs)
or for gain factors in pixel_gain:
(common_mode(raw - peds))*gfactor * mask(**kwargs)
Mask
To construct the mask use **kwargs and algorithms from method mask_v2 from AreaDetector.
TURN OFF common mode correction
For cmpars = None - default constants are used
For regular detectors: cmpars = 0 or cmpars[0] = 0 - OFF
For epix10ka and Jungfrau cmpars[1] = 0 - OFF
See also Common mode correction algorithms.
Detector dependent algorithms
Spreadsheet below contains comments on detector specific application
| Detector type | pedestal subtraction | common mode correction | pixel_gain content, by default gain factor | gain | mask | formula | comments |
|---|---|---|---|---|---|---|---|
| LCLS (1) | |||||||
| CSPAD | + | default cmpars = (1, 25, 25, 100) cmpars = 0 or cmpars[0] = 0 | gain factor, keV/ADU | *gainmask det.set_gain_mask_factor(gfactor=6.85) | + | gain map extracted from detector configuration data and applied with gfactor gainmask is applied before regular gain factor | |
| CSPAD2x2 | + | shape=(185, 388, 2) → common_mode shape=(2, 185, 388) → back to (185, 388, 2) default cmpars = (1,25,25,100) | gain factor, keV/ADU | + | + | shape is converted before common mode correction in order to apply regular CSPAD algorithm then it is converted back to daq shape. | |
| epix100a | + | default cmpars =(4,6,30,30) | gain factor, keV/ADU | + | + | ||
| pnCCD | + | default cmpars =(3,350,350,128) or alg #8 (8,5,500) | + | + | |||
| Andor3d | + | default cmpars =(2,10,10,cols) | + | + | |||
| Princeton | + | default cmpars =(1,50,50,100,1,size,1) | + | + | |||
| Camera | + | other Cameras default cmpars = (0,0,0,0), cmpars = 0 or cmpars[0] = 0 - OFF | + | + | |||
| epix10ka | + |
| gain, ADU/keV | pixel_gain constants are used and per event depending on gain range | + | (common_mode(raw - peds)/gain * mask | UtilsEpix10ka.calib_epix10ka_any(det, evt, cmpars=None, **kwa) offsets are already accounted at deployment of pedestals in calib/.../pedestals |
| Jungfrau | + | applied for pixels in high gain mode only in combination with mask
| gain, ADU/keV | pixel_gain and pixel_offset are used and per event depend on gain range | + | (common_mode(raw - peds - offset))/gain * mask | UtilsJungfrau.calib_jungfrau(det, evt, cmpars=(7,3,200,10), **kwa) |
LCLS-II Detector Interface
Method calib
arr = det.raw.calib(evt, **kwa)
Regular sequence of applied algorithms
- dark correction - pedestals subtraction using constants of ctype
pedestalsfrom DB - common mode correction depending on cmpars or constants of ctype
common_modefrom DB - gain correction with constants from DB for ctype pixel_gain. In LCLS-II we intend to always use in pixel_gain constants the gains in ADU/keV.
- mask is not applied by default (see below)
Correction formula
common_mode(raw-peds)/gain
Mask
In lcls2 mask is derived and applied separately as explained in Area detector mask examples or Detector interfase in LCLS-II.
TURN OFF common mode correction
cmpars=None - use constants from DBcmpars[1] = 0 - OFFboth cmpars=None and common_mode constants are missing in DB - common mode correction is OFF
Detector dependent algorithms
Spreadsheet below contains comments on detector specific application
| Detector type | pedestal subtraction | common mode correction | gain | mask | formula | comments |
|---|---|---|---|---|---|---|
| LCLS-II | ||||||
| epix10ka | + | default cmpars=None - search common_mode pars in DB. Correction is OFF if constants missing in DB. ex. (7,2,100,10) | + | - | (common_mode(raw - peds)/gain | calib_epix10ka_any(det.raw, evt, cmpars=None, **kwa) mask defined by **kwa is used in common_mode_correction see UtilsEpix10ka |
| epixhr2x2 | + | + the same as epix10ka | + | - | the same as epix10ka | |
| epix100a | + | + the same as epix10ka ex. (7,7,100,10) | + | - | calib_epix100(det.raw, evt, cmpars=None, **kwa) | |
| opal | + | - | + | - | (raw-peds)/gain | opal_base |
| piranha4 | + | - | + | - | (raw-peds)/gain | piranha4_base |
References
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