Using the SLAC Installation of the Geant4 Toolkit

Last modified :

Current Installation

Release Tag - the release tag of the current installation is geant4-09-01-p01-patch-00. This is a local patch of Geant4 9.1 p01
Previous releases still available:
- /afs/slac/package/geant4/vol2/G4Home/geant4-09-00-ref-00-patch-00
- /afs/slac/package/geant4/vol1/G4Home/geant4-08-02-ref-00-patch-00
- /afs/slac/package/geant4/vol4/G4Home/geant4-08-00-p01-patch-00

Supported Platforms:
- Linux - noric, yakut

Data files for optional Geant4 processes and models are centrally located at /afs/slac/package/geant4/vol29. If these processes are used, environment variables must be set which point to one or more of the following directories:
- G4EMLOW4.3: for low energy electromagnetic processes
- G4NDL3.11: neutron data files for high-precision neutron models which include thermal cross sections
- PhotonEvaporation2.0: photon evaporation
- RadioactiveDecay3.2: radioactive decay for hadronic processes

Accessing the SLAC installation

To compile and link a simulation executable using the current Geant4 toolkit, several environment variables must first be set. A script which does this is found in

/afs/slac/package/geant4/vol3/G4Home/g4setup.env

To begin:

choose a work directory, for example, mytestdir
copy the above g4setup.env file to it
modify the line in the file which sets the G4WORKDIR environment variable so that it reads: setenv G4WORKDIR $HOME/mytestdir
source g4setup.env

The essential variables set by this file are:

G4WORKDIR - working directory which will contain your specific code and the binary application
G4INSTALL - location of the installed code and libraries
G4SYSTEM - G4 code for the system architecture
CLHEP_BASE_DIR - base directory of the CLHEP libraries against which the toolkitis linked and against which your code should be linked
CLHEP_LIB - location in the SLAC directory structure of CLHEP libraries built for a given platform

Visualization

Interfaces for several visualization drivers have been compiled into the toolkit libraries. The user must choose which one to use and set the appropriate environment variable before building the executable. A list of the available drivers is given in g4setup.env. In this example OPENGL is chosen.

Building and Running the Executable

The following steps will lead you to a working executable with visualization using OPENGL:

go to your work directory (in the above example, mytestdir)
from the Geant4 installation copy the code for example 3:
- cp -r $G4INSTALL/examples/novice/N03 N03
cd to N03
gmake
- gmake will create tmp and bin directories in your work directory. The executable, named exampleN03, will be in /bin/$G4SYSTEM/
while in directory N03, run the executable:
- ../bin/$G4SYSTEM/exampleN03
if everything goes according to plan, you should see the Idle> prompt on your screen (after some preliminary output). From this prompt type
- /run/beamOn 1
to see an event displayed. Repeat until you get tired or bored.
when finished type
- exit
at the Idle> prompt.

At this point you are ready to add to and modify the code in your copy of N03. For more information about developing your own simulation code using Geant4, see the Application Developer's Guide .

Dennis Wright