Install version 4.10.07.p01 of the Geant4 libraries. You will need the data files for low energy electromagnetic processes, photon evaporation, and radioactive decay.
Set up your environment (consider adding this to your .bashrc):
$ source <Path to Geant4>/bin/geant4.sh
$ source <Path to Geant4>/share/Geant4-10.6.3/geant4make/geant4make.sh
Compile:
$ make
(Run the examples by typing make at the command line in the corresponding directory.)
This is a simple example collecting a spectrum with a single NaI detector from a 137Cs source. A sorting code NaISort.py is included which produces a histogram in the .mca format (requires python3 and the numpy module). A Makefile is included.
This example simulates two NaI detectors collecting spectra from a 22Na source centered between them, and off center. The coincSort.py sorts a coincidence matrix and the spectrum of detector 2 gated on an energy range in spectrum 1. The gate range is set in the file coincSort.inp and is set to 0-2000 keV by default. (Gating in the range 1225 - 1325 keV shows coincidences with the 1274 keV transition in the 22Ne daughter and the 511 keV gamma rays from the e+ - e- annihilation.)
/NaI/setX <double> <unit>
/NaI/setY <double> <unit>
/NaI/setZ <double> <unit>
Set the position of the detector.
/NaI/rotateX <double> <unit>
/NaI/rotateY <double> <unit>
/NaI/rotateZ <double> <unit>
Orient the detector by rotating about X, Y, Z.
/NaI/GeometryFile <filename>
Set the name of the optional geometry file. If this command is present, a NaI detector is placed for each line in the specified file. Each line has the format:
<X (mm)> <Y (mm)> <Z (mm)> <X rotation (deg)> <Y rotation (deg)> <Z rotation (deg)>
If a geometry file is specified, the positioning and rotation commands above are ignored.
Realistic simulations of radioactive sources can be run as illustrated by ./examples/cs137/cs137.mac. The Simple source is a computationally more efficient alternative.
/Source/Simple <double> <unit>
Use a simple monoenergetic gamma-ray source with the specified energy.
/Source/setX <double> <unit>
/Source/setY <double> <unit>
/Source/setZ <double> <unit>
Set the position of the source (and capsule if present).
/Source/Capsule/rotateX <double> <unit>
/Source/Capsule/rotateY <double> <unit>
/Source/Capsule/rotateZ <double> <unit>
Orient the source capsule by rotating about X, Y, Z.
/Source/Capsule/Construct
Include the source capsule. Must be issued after the source positioning and capsule rotation commands.
Optionally, 2" x 4" x 6" lead bricks can be included in simulations.
/Brick/setX <double> <unit>
/Brick/setY <double> <unit>
/Brick/setZ <double> <unit>
Set the position of the brick.
/Brick/rotateX <double> <unit>
/Brick/rotateY <double> <unit>
/Brick/rotateZ <double> <unit>
Orient the brick by rotating about X, Y, Z. (The order of these commands matters.)
/Brick/GeometryFile <filename>
Set the name of the optional geometry file. If this command is present, a brick is placed for each line in the specified file. Each line has the format:
<X (mm)> <Y (mm)> <Z (mm)> <X rotation (deg)> <Y rotation (deg)> <Z rotation (deg)>
If a geometry file is specified, the positioning and rotation commands above are ignored.
/Brick/Construct
Include the brick. Must be issued after the positioning and rotation commands.
Optionally, cylindrical aluminum targets can be included in simulations.
/Target/setR <double> <unit>
Set the radius of the target(s).
/Target/setL <double> <unit>
Set the length of the target(s).
/Target/setX <double> <unit>
/Target/setY <double> <unit>
/Target/setZ <double> <unit>
Set the position of the target.
/Target/rotateX <double> <unit>
/Target/rotateY <double> <unit>
/Target/rotateZ <double> <unit>
Orient the target by rotating about X, Y, Z. (The order of these commands matters.)
/Target/GeometryFile <filename>
Set the name of the optional geometry file. If this command is present, a target is placed for each line in the specified file. Each line has the format:
<X (mm)> <Y (mm)> <Z (mm)> <X rotation (deg)> <Y rotation (deg)> <Z rotation (deg)>
If a geometry file is specified, the positioning and rotation commands above are ignored.
/Target/Construct
Include the target(s). Must be issued after the positioning and rotation commands.
Output is written to a text file. Each line represents a detected event and has the format:
<Event> <Detector ID> <Energy> <Hit X> <Hit Y> <Hit Z> <Full Energy>
<Event>: event number<Detector ID>: integer identifying the detector registering the event<Energy>: energy deposited in keV<Hit X>,<Hit Y>,<Hit Z>: hit position in mm<Full Energy>: == 1 if the gamma ray deposited its total energy in the detector, == 0 otherwise
Run the macro file vis/vis.mac an interactive session:
$ UCNaI
Idle> /control/execute vis/vis.mac
Idle> exit
This generates a VRML 2 file named g4_XX.wrl which can be viewed with a VRML viewer (like view3dscene, FreeWRL, or mayavi2).
The macro file ./vis/trajectories.mac illustrates how to add particle trajectories to visualizations.