Calibration process is initiated, when a File/scan command with option ``s'' is executed. The first and the last entries given in this command show the range of entries, among which events for calibration will be selected. It can be used by the different ways.
One way is to execute a File/scan command with option ``s'' before the basic scanning command, and then during the basic scan the new calculated calibration constants will be used (see example below).
Another way is to include ``s'' option in the basic scanning command. In this way the calibration constants are calculated using the data of all of scanning entries and are used for the next seance of scanning of the same or another data file.
Of course, the second way allows to calculate calibration constants on the big statistics, which gives more quantity of fired shower detector blocks and hence more block constants computed. But for choosing of one of these ways one must take into account CPU time and disk free memory, which are required for calibration performance. The following table may be useful to choose one of the way for calibration and/or to choose the optimal number of entries in the calibration command.
| Entries | CPU time | Disk memory |
| 5000 | 44 sec | ~160 KB |
| 10000 | 1.45 min | ~330 KB |
| 20000 | 3.33 min | ~650 KB |
| 50000 | 8.37 min | ~1600 KB |
| 100000 | ~17 min | ~3300 KB |
According to us the optimal is approximately 5000-50000 entries.
A simple example of KUMAC file for shower detector calibration and then Shower clusters energies distribution saving, approximately looks as follows.
*****************************************************
define/batch on
*********************** Setup files *******************
set/file/header hdr_1690
set/file/output spec_1s1690.hbook
set/file/database db_coin_new
set/file/detmap detmap.config
************* Shower Detector Calibration *************
file/scan e89003_1690.dat FIRST=1 LAST=5000 -s
***************** Scanning and output ****************
spectra/save spec_e.show.cl_e
file/scan e89003_1690.dat FIRST=1 LAST=10000
spectra/write
return
*****************************************************
After the necessary files definition commands, the calibration constants calculation is started by the File/scan e89003_1690.dat FIRST=1 LAST=5000 -s command, which is performed on two stages.
On the first stage, entries from 1 to 5000 are scanned, and calibration events are selected among these entries. The calibration events are selected such, that the charged particle is electron with the biggest probability. The calibration events data (momentum of particle, fired blocks numbers and corresponding amplitudes values in these blocks) are written into the temporary file shcal_events.dat_tmp in the current directory.
On the second stage, the calibration constants of the channels of Preshower and Shower are calculated (using the calibration events data) and saved into the two disk files: shower_calib.dat and shower_calib_rXXXX.dat (where XXXX is the run number of currently data processed data file).
Each of files shower_calib.dat and shower_calib_rXXXX.dat contains the same information (Calibration constants values, mean Pedestal and its Sigma-s values for all Preshower and Shower channels) and occupies 4824 bayt of disk memory.
Two similar calibration constants files creation allows to use constants during any run data processing, by following: 1) If calibration for this run has been done previously, then use the run's own calibration constants; 2) Otherwise, one can use the latest calculated constants (see program read_show_coef).
In present it assumed, that shower_calib.dat and shower_calib_rXXXX.dat files, also file of the shower detector channels Pedestals mean values shower_peds.dat, are the current directory files (see programs read_show_coef, read_show_peds and notes to these programs).
After the shower detector calibration, KUMAC program described before saves spectrum of energy deposition in the Shower, scans the first 10000 entries of the data file, writes spectrum into the disk and exits to the Espace main menu.
Note, that the second File/scan command is executed without ``s'' option. In this case, neither calibration events selection no calibration constants calculation is made. So, user can include or no calibration command in own KUMAC program in dependence of disk quota, or cpu limit possibilities, or other reasons.
If user don't want make shower detector calibration, he can use either the already existing constants file, or built in program read_show_coef ones.
Distributions, histograms of which are shown in Fig.1, have been created for 10000 entries of data run 1690. In this distributions p is particle momentum corrected by kinematics and e is sum of energy depositions of particle in Preshower and Shower.
Calibration constants, using of which these energy depositions are computed, have been calculated by calibration events, selected among the first 100000 entries of data file.