Grinnell-ISU Simulation Package
How to do everything in the instruction typing mode?
The simulation of an Air-Cherenkov Experiment can be subdivided in three steps:
-Simulating the Cherenkov light arriving on the detector.
-Simulating the response of the detector to the Cherenkov light. The output should look exactly the same as real data.
-Analyzing the simulated detector output as well as analyzing real data.
This operation involves two programs: The kascade program simulates the development of the shower and the cherenkf7 program simulates the Cherenkov light produced by the shower and drops the photons on the telescope. Note that all versions of kascade have the same "kascade" executable code name.
- Simulating the Cherenkov light arriving on the detector.
In order to start the shower simulation type:
The program kascade will then read by default, kascade.pilot, which contains the number of showers to be simulated, the energy spectrum and other things (see our kascade section). The output of kascade consists of particle track records. The output is made directly on the standard output or to a file (see kascade.pilot).
Should you wish to use a kascade.pilot file with a different name, you may enter this name on the kascade command line:
Simulation/Shower/kascade <new pilot filename>
A problem that often occurs is that the program attempts to create an output file, such as a log file or a segment file, which already exists. In such case, you have to move the file or change the file name you want to use for the output and then rerun kascade.
Then you may want to generate the Cherenkov light that these shower are producing over the detector. Stay in /GrISU and edit the file cherenkov.pilot which controls the operation of cherenkf7. For help on this pilot file look at our cherenkf section. The you can type
Simulation/Cherenk/cherenkf7 < Dump/myshowers.seg
or if you prefer to avoid generating the particles tracks segments file just type:
Simulation/Shower/kascade | Simulation/Cherenk/cherenkf7
Once again, you may use a pilot file with a name different from cherenkov.pilot by placing this name on the cherenkf7 command line.
cherenkf7 will then read the particle track segments and write the Cherenkov photons in the output file specified in cherenkov.pilot (or the file specified on the command line). The output from cherenkf7 overwrites existing files.
Stay in the ./GrISU directory. You can edit the detector.pilot file to control the operation of grisudet. For help, see our grisudet section. In short, you should set the configuration file to be the same as used by cherenkf7, set a file name for the output (e.g.: Data/Raw/myshowers.rec), specify the Cherenkov photons file(s) for cherenkf7 to read. Then you simply type
Once again, you may use a pilot file with a name different from detector.pilot by placing this name on the above grisudet command line.
The analysis works in the same way as grisudet. You stay in ./GrISU where you can edit analysis.pilot in which you can specify the input and output file names, the configuration file to be used, etc. Then, since analysis.c can also be used with real data, there are OPTIONAL command-line options that override the analysis.pilot filenames to make it easier to use analysis.c with a script calling analysis separately for each data file. To run the code, just use the following:
Analysis/analysis [-d <pilot filename> -g <gain filename> -p <pedestal filename>]
When the program finishes, you should find the output file (.par) along with an other file with the same name but with the extension .kumac. This is a kumac program which can be used in PAW to load the ntuple of your analysis parameters. (for more information on the analysis program, see our analysis section). If you elect to produce a .kumac file for a large number of simulated showers, you will create a very large file; of course, you can elect not to produce a .kumac file by not specifying the kumac line in analysis.pilot.
Once again, you may use a pilot file with a name different from analysis.pilot by placing this name on the above analysis command line.
In order to measure the blur spot size used in the simulation, one can use make_photons to generate photons all coming from the same direction as follows:
The number of photons, the radius over which the photons will arrive on the ground (the telescope is assumed to be centered on 0,0) or on the camera, and other parameters are specified in the pilot file, make_photons.pilot. For further documentation on make_photons, see the make_photons documentation; use the Utilities documentation link.
The file can be read by grisudet,possibly with the option * OPTIC activated in detector.pilot and pointing to a file Data/TestOptics/mytest.opt which can be explored from PAW using optics.kumac.