Using the SLAC Installation of the Geant4 Toolkit with the JAIDA-G4 Analysis Package

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Introduction

A recipe for building and running a simulation executable using the Geant4 toolkit and the JAIDA-G4 analysis package is provided. Libraries for both of these packages are installed and maintained by the SLAC Geant4 group so that users need only link their applications to them. As a starting point for new users, a Geant4 example with histogramming has been provided.

Current Installation

The latest Geant4 libraries are centrally maintained and installed so that users may build and link their applications to them, rather than build and maintain their own libraries.
Geant4 9.3 (patch 01) is now installed on the 32-bit and 64-bit Linux machines:

rhel4-32
rhel5-32
rhel4-64
rhel5-64

Access to older libraries is available upon request.
Various data files required for optional Geant4 processes and models are also centrally maintained and automatically accessed by the setup scripts.

This analysis example requires the JAIDA-G4 package. This package and its examples were originally prepared for the SLAC Geant4 Workshop of February 2002. The file names, tree configuration and setup scripts have been modified in the current SLAC installation. JAIDA-G4 is supported on the platforms listed above.

Accessing the SLAC installations

To compile and link a simulation executable using the current Geant4 toolkit and the JAIDA analysis package, several environment variables must first be set. This can be done as follows:

choose a work directory, for example, mytestdir
copy to it the files

/afs/slac/package/geant4/g4setup.env
and
/afs/slac/package/geant4/vol0/analysis/jaida.env

Important Notice: the current example requires JAIDA Version 3. A fresh download of jaida.env is required in order to get the latest libraries.
in g4setup.env modify the line in the file which sets the G4WORKDIR environment variable so that it reads:
setenv G4WORKDIR $HOME/mytestdir
source g4setup.env
source jaida.env (g4setup.env must be sourced first)

The essential variables set by g4setup.env 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

The essential variables set by aida.env file are:

JDK_HOME - Java home directory
G4ANALYSIS_USE - enables Geant4 analysis packages
JAIDA_HOME - base directory for the JAIDA (ver.3.2.1) package
AIDAJNI_HOME - base directory for the JAIDAJNI (ver.3.2.1) package

Visualization

Currently, OPENGLX and JAS cannot run simultaneously, so the environment variable G4VIS_USE_OPENGLX is unset in the script.

Building and Running the Executable

The following steps will lead you to a working executable with histogramming:

go to your work directory: cd $G4WORKDIR
from the G4-JAIDA installation copy the code for example A01:
- cp -pr $G4INSTALL/examples/extended/analysis/A01 A01
cd to A01
gmake clean
gmake
- gmake will create tmp and bin directories in your work directory. The executable, named A01app, will be in /bin/$G4SYSTEM/
while in directory A01, run the executable:
- ../bin/$G4SYSTEM/A01app
- which will bring up the interactive prompt:
  Idle>
- to run 10 events you can now enter
  /run/beamOn 10
- if all goes well, a JAS window will appear containing two histograms and three scatterplots.
- to terminate the job, at the prompt enter
  exit
- currently you must also close the JAS-AIDA window to get the job to stop.
- in the A01 directory will be a file A01.aida which contains the plots. To examine them
  - /usr/local.bin/jas3 & or jas3 &

At this point you are ready to add to and modify the code in your copy of A01. To learn more about developing your own simulation code using Geant4, see the Application Developer's Guide .

Tatsumi Koi