Requires

• Geant4
• yaml-cpp (version >0.5)
• Boost (headers required by yaml-cpp)
• HDF5 C library

Compiling

The software uses CMake to manage the building process.

For Geant4 you need to source the Geant4 environment beforehand. This is necessary for running the simulation as well, because Geant4 uses the environment variables to find the data files.

If the other necessary libraries are installed at custom locations, you can specify the paths when configuring the build using -D flags (YAMLCPP_DIR for yaml-cpp and BOOST_ROOT for Boost). Since the FindBoost.cmake module seems to be a bit crappy, a Boost_NO_BOOST_CMAKE=ON is also probably necessary if there is an older Boost installed on the system as well (otherwise the module may find a wrong version).

The FindHDF5.cmake script is a bit stupid and you have to specify the HDF5_ROOT as an environment variable (e.g. HDF5_ROOT=path cmake ...).

In order to have a debug build you can use the standard CMAKE_BUILD_TYPE.

Usage

$ ./fgamma --help
Usage: fgamma [OPTION...] [EVENT...]
Simulation of gamma-rays produced in the atmosphere by cosmic rays.

 General options:
  -f, --eventfile=FILE       file with event parameters (each line with
                             eventconf syntax)
  -o, --prefix=PREFIX        set the prefix of the output files
      --seed=SEED            set the seed for the random generators; if this is
                             not specified, time(0) is used)
      --tracks               store tracks in tracks.txt
  -v, --verbosity=LEVEL      set the verbosity level (0 - minimal, 1 - a bit
                             (default), 2 - a lot)
      --vis                  open the GUI instead of running the simulation

 Options for tweaking the physics:
      --cutoff=CUT           define an energy cutoff (in GeVs)
  -m, --model=MODELFILE      set the YAML file used to model the geometry
                             (default: model.yml)
      --spaceonly            only accept particles on the outer boundary

 Other:
  -?, --help                 Give this help list
      --usage                Give a short usage message
  -V, --version              Print program version

Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.

The parameters of the inital particles in the simulation can be supplied on the command line, in a file or both. All non-option arguments on the command line are interpreted as event paramters. The -f option can be used to define a file where additional events will be read from (one event per line).

Each event parameter (argument or line) is a comma-separated list of values in the form name=value. The possible parameters are:

• E or e -- energy of the incoming particle (in GeV)
• aoi -- angle of incidence (real number between 0 and 1, where 0 corresponds to 0 degrees and 1 to 90 degrees; default: 0)
• pid -- PDG ID of the incoming particle (default: 2212, proton)
• n -- number of events with these parameters (default: 1)

All parameters except energy have default values and can therefore be omitted.

An example: ./fgamma E=100 E=10,n=25 E=10,pid=11,aoi=0.5 -- 1 event with 100 GeV proton, 25 events with a 10 GeV proton and an event with a 10 GeV electron coming in at a 45 degree angle.