Dectris PILATUS - Loading Trim Files and Setting the Threshold Automatically

User_Manual-PILATUS-V1_2.doc 45/57
10.6 Loading trim files and setting the threshold
automatically
In order set the trimfiles for an arbitrary treshold between 6 and 12 keV the
camserver command setthreshold is used.
This simplifies the operation and makes sure that the detector is allways used
trimmed.
For the target threshold T, the closest available trim_file is loaded and vcmp is
calculated to match the target threshold T. In normal operation, the threshold
should always be set to 50% of the energy of the incoming X-rays.
In cases where fluorescence radiation from a sample should be suppressed
the threshold should be set about 0.5 keV above the energy of the emitted X-
rays.
Command Description
SetThreshold gain
threshold
SetThreshold - set gain (energy range) and threshold
energy T
Usage:
setthreshold [[gain] threshold]
1) if parameters are omitted, the current settings are
shown
2) gain is 'uhighG', 'highG', 'midG' (standard) or 'lowG'
3) if gain is omitted, the previous setting is retained
4) threshold is in eV
5) this command builds a script in
"/tmp/setthreshold.dat" and then loads it. The data for
building the script are read, e.g., from
p2_det/config/cam_data/m169_calibration.def.
gain Vrf Description Tau [ns]
Uhighg
-0.1 Very slow settings with ultra high gain
for best resolution at low energies: 2 –
5 keV
~2000
Highg
-0.15 Slow settings with high gain for best
resolution at low energies: 3 – 6 keV
384
Midg -0.2 Standard settings for energies between
5 – 18 keV
200
lowg -0.3 Fast setting with low gain for best
performance at high energies and high
rates: 7 – 30 keV
125