Issue
Xiaozhe complains that too many pixels outside signal region in ueddaq02 r401 shows up in selection of intensities between 100 and 500 keV.
Research
Issue demo
det.raw.calib(evt) for ueddaq02 r401, selection of intensities between 100 and 500 keV
Check correctness of loaded calibration constants
metadata consistent with last dark run ueddaq02 r398 for pedestals, pixel_gaim, pixel_rms, pixel_status:
metadata for pedestals
pedestal metadata: {'_id': '6049c3c1baf79f747df38a05', 'experiment': 'ueddaq02', 'run': 398, 'run_end': 'end', 'detector': 'epix10ka_000001', 'ctype': 'pedestals', 'dtype': 'ndarray', 'time_sec': '1615182592', 'time_stamp': '2021-03-07T21:49:52-0800', 'version': 'V2021-03-04', 'comment': 'no comment', 'uid': 'xshen', 'host': 'psanagpu102', 'cwd': '/cds/home/x/xshen', 'id_data': '6049c3c1c88c56b170aaf7b3', 'id_doc_exp': 0, 'id_data_exp': 0, 'detname': 'epixquad', 'longname': 'epix10ka_3926196238-0175152897-1157627926-0000000000-0000000000-0000000000-0000000000_3926196238-0174824449-0268435478-0000000000-0000000000-0000000000-0000000000_3926196238-0175552257-3456106518-0000000000-0000000000-0000000000-0000000000_3926196238-0176373505-4043309078-0000000000-0000000000-0000000000-0000000000', 'shortname': 'epix10ka_000001', 'dettype': 'epix10ka', 'run_orig': 398, 'tstamp_orig': '2021-03-07T21:49:52-0800', 'extpars': '{"content": "extended parameters dict->json->str", "command": "/cds/home/opr/uedopr/git/lcls2_210310/install/bin/epix10ka_deploy_constants -e ueddaq02 -d epixquad -r398 -D -L INFO"}', 'data_type': 'ndarray', 'data_dtype': 'float32', 'data_size': '3784704', 'data_ndim': '4', 'data_shape': '(7, 4, 352, 384)'}
Basic plots
Panel index 0-3, gain range index for event 5 is 2 (FL), Gain factor(for grind=2) 0.164
RMS(FL), pedestals(FL), raw for event 5,
Event 5: raw-peds (ADU), (raw-peds)/gain (keV), calib (keV)
Event 5 (raw-peds)/gain (keV) for hot and cold ASICs
Summary
- constants for ueddaq02 r401 are loaded correctly from the latest dark run r398
- default gain factor for FL is 0.164 ADU/keV (or ~6 keV/ADU)
- numeration of panels is defined in geometry looks correct
- per-pixel gain range index is defined correctly =2 for FL.
- pedestal subtraction works as expected: raw-peds has mean=0.6 ADU, raw RMS shrinks from 170 ADU to ~3 ADU raw-peds.
- there may be a minor common mode offset ~0.6ADU, but common mode is not corrected for FL. Even if it is corrected, this would not resolve this issue.
- default gain factor is defined correctly for FL is 0.164 ADU/keV
- rms defined in dark r398 shows that panel/banks have significant spread/noise variation of factor 2-3 between panels.
- plots of calib for "hot" and "cold" ASICs show that RMS is significantly different.
- in this case application of the common threshold is a bad idea
Recommendations
- Check if hardware could be set to perform more uniformly in terms of noise/rms spread
- At analysis level use per-pixel thresholds defined in terms of "number of dark RMS".
References
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