thr - Tcl/Tk script help
please note: this file was generate by make_tcl
from the file: thr.hlp. Please update that file
and regenerate the thr.html. Do not update the thr.html file directly!
intro
The bgocal.tcl Tcl/Tk script is used to find and set the germanium and BGO detector thresholds. In addition, the script allows for a manual setting of thresholds on the BGO and germanium detectors and for a manual setting of walks on the germaniums. The script also allows the user to store threshold and walk parameters in files and later recover and re-load these parameters.
enabled
A list of event filter formatters and germanium detectors can be specified using the 'sunken' windows at the top of the script. This allows for a selected calibration of detectors (and bad detectors can be avoided). The format is the usual Bob Belshe format. For instance, to specify all germanium detectors from 1 to 30 except detectors 2, 13, 14, 15 and 21 use the following string: '1,3-12,16-20,22-30. The same rule applies to the event filter formatters - although mostly this string would just be '1-6'. All parameters in this script are stored in a file that is read when the script is invoked (by selecting the threshold entry in the CALibration openwin menu of the gs account). The current parameters are stored in this file when the 'store basic parameters as default selection' is pushed.
threshold
The thresholds on the germanium and BGO detectors are set by specifying a DAC value between 0 and 255 (8 bits) in the GE-BGO cards. The procedure in this script for setting the correct dac value is as follows: i) the dac value is set to a high value ( = 'start reg val 0..255' input), ii) the spectra in the EFFs are zapped. iii) the threshold DAC value is now lowered until counts are seen in the channel that is specified in the 'threshold chan val no'. This procedure is very simple and does not require any knowledge of the calibration of the DAC in the GE-BGO board! However, he detectors must be energy calibrated for the threshold channel to have a meaning of a specific energy threshold. The drawback of the method is that the procedure does take some time to do since the dac's are lowered one unit at a time. However, it is not expected that the thresholds are changed too often and, moreover, all the germanium detectors are processed in parallel. While one detectors dac is changed, data is accumulated in the other detectors.
Note and warning: This procedure has not been checked online yet!
set_thr_walk
COMMON thresholds and walk DAC values can be loaded into the GE_BGO boards by specifying the DAC values (0...255) in the sunken window and pushing the appropriate 'set...' button. Only the germaniums that are selected are affected by this operation
save_restore
The current threshold and walk DAC values in the GE_BGO boards can be read out and stored in the files specified in the lower part of the script. Likewise the values in these files can be recovered and stored in the Ge_BGO boards. The blue buttons are for 'get' functions and the red buttons are for 'put' operations.