Author: W. Pokorski(1), I. Hrivnacova(2)
(1) CERN
(2) Institut de Physique Nucléaire (IPNO), Université Paris-Sud, CNRS-IN2P3
Examples in the physicslist category show the possible ways how to define a physics list from Geant4 physics constructors. This example demonstrates the usage of G4GenericPhysicsList to build the concrete physics list at the run time.

In Geant4 versions < 10.4, the generic physics list was demonstrated in the extended/hadronic/Hadr05 example.

The G4GenericPhysicsList class allows to build the physics list at the run time in two possible ways, either by processing a macro file containing the 'physics list' or by passing a vector of 'physics constructors' names to the constructor of the class.

To run the example you can call

./genericPL -m run.mac [ -p FTFP_BERT.mac ]

where FTFP_BERT.mac is the macro file containing the 'physics list'.

If you run this example by calling

./genericPL -m run.mac

the physics list will be constructed by using a vector of the names of the different physics constructor defined in the genericPL.cc file.

The same experimental setup is used for all examples in the physicslist category:

Detector description

The geometry (defined in the DetectorConstruction class) consists in a box of scintillator material (CsI) followed by a thin box of air (screen) which is used to simplify scoring.

Primary generator

The primary generator is defined with usage of G4ParticleGun. The default particle is proton which hits the box perpendicular to the input face. The type of the particle and its energy are set in the PrimaryGeneratorAction class, and can be changed via the G4 built-in commands of the G4ParticleGun class.

Scoring (ntuples)

The screen volume is associated with a sensitive detector, ScreenSD, which accounts the following particle properties:

trackID
particle PDG encoding
particle kinetic energy
particle X,Y position
particle time

The scored quantities are filled in the Screen ntuple, which is defined using G4AnalysisManager in RunAction class. The ntuple is saved in a Root file, which name is set to be equal to the example name in main () function.

How to build

An additional step is needed when building the example with GNUmake due to using the extra shared directory:

 % cd path_to_example/example
 % gmake setup
 % gmake

This will copy the files from shared in the example include and src; to remove these files:

 % gmake clean_setup