Gabriele Cosmo\page ExampleChem3 Example chem3
General description
This example is provided by the Geant4-DNA collaboration.
These processes and models are further described at: http://geant4-dna.org
Any report or published results obtained using the Geant4-DNA software shall cite the following Geant4-DNA collaboration publications: Phys. Med. 31 (2015) 861-874 Med. Phys. 37 (2010) 4692-4708
How to activate chemistry code. How to set minimum time step limits using TimeStepAction.
GEOMETRY DEFINITION
It is a simple sphere which represents a 'semi infinite' homogeneous medium.
Two parameters define the geometry :
- the material of the sphere,
- the full size of the sphere.
The default geometry is constructed in DetectorConstruction class, but all of the above parameters can be changed interactively via the commands defined in the DetectorMessenger class.
PHYSICS LIST
The physics list is initialized in G4EmDNAChemistry, together with chemical stage models configuration.
AN EVENT: THE PRIMARY GENERATOR
The primary kinematic consists of a single particle starting at the center of the sphere. The type of the particle and its energy are set in the PrimaryGeneratorAction class, and can be changed via the G4 build-in commands of G4ParticleGun class. The chemistry module is triggered in the StackingAction class when all physical tracks have been processed.
HOW TO START ?
Run the example from build directory.
To run the example in batch mode
./chem3 -mac beam.in
or
./chem3
then the macro beam.in is processed by default
In interactive mode, run:
./chem3 -gui
or
./chem3 -gui gui.mac
The user interface will be launched. Continue using /run/beamOn 1 command. By default, the vis.mac visualization macro is called. The vis_vm,.mac macro is used only in the context of the G4DNA tutorial hands-ons.
OUTPUT
Physics initialization and the defined reaction table are printed. G4ITStepManager processes the chemical stage time step after time step. Chemical reactions are printed. In the GUI window a cummulative trajectory of the chemical species is drawn.
The functions in TimeStepAction show how to get species ID, positions at each time step or in a chemical reaction
TIME EVOLUTION VISUALIZATION
User can start a visualization of the chemical track evolution in time and space using /control/execute movie.mac. (The movie.mac macro then executes the movie_prep.mac, movie_chemistry.mac and movie_physics.mac macros.) Note, that in default setup the simulation requires machine with 6 GB of RAM. To lower memory requirements, either decrease energy of the incident electron in prep.mac or/and shorten the simulation using SetEndTime setting in src/ActionInitialization.cc.