Geant4 9.0 Release Notes
June 29th, 2007

The code and binary libraries for the supported systems are available through our Source Code Web page.

Please refer to the Geant4 User Documentation for further information about using Geant4.


  1. Supported and Tested Platforms
  2. CLHEP and AIDA
  3. Items for migration of the user code
  4. New Developments and Capabilities
  5. Expected effects on physics and performance
  6. Known Run-Time Problems and Limitations
  7. Compilation Warnings
  8. Known Run-Time Warnings
  9. Geant4 Software License
  10. Detailed list of changes and fixes

1. Supported and Tested Platforms

Official platforms: More verified configurations: Platforms configured but not tested and not supported:


Geant4 9.0 requires the installation of CLHEP.
Tests have been performed with CLHEP-
The software has been verified also with CLHEP-

Geant4 9.0 examples with histogramming cowork with analysis tools compliant to AIDA 3.2.1 interfaces.
AIDA headers can be downloaded from:

3. Items for migration of the user code

Listed here is some relevant information on developments included in this release, some of which may require migrations (mainly for advanced uses of features in Geant4) in order to upgrade from release 8.3 to release 9.0. Note that a full re-installation of libraries (or a full recompilation) and a recompilation of user applications is anyhow required.


The static constants for the geometrical tolerance kCarTolerance, kRadTolerance and kAngTolerance which used to be defined at global scope, have been now removed.
Advanced applications making use of such constants in the code are required to retrieve the values for Cartesian, Angular and Radial tolerances through the class G4GeometryTolerance, a new class providing the methods, respectively: GetSurfaceTolerance(), GetRadialTolerance() and GetAngularTolerance(). Applications with setups of unusual dimensions (e.g. smaller than 1 mm or larger than 1 km) can now adjust these values, and must do so before creating any part of the geometry description. Please see the User's Guide for Application Developers for the details.

Biasing & Scoring

Standard Electromagnetic physics

A few methods of the interface classes G4VEmModel, G4VEnergyLossProcess, G4VEmProcess, G4VMultipleScattering were revised, in order to reduce memory allocations. All classes inheriting these interfaces were modified accordingly (see detailed list of changes). Advanced users with derived classes must make similar changes.

Old implementations of physics processes, of configurations frozen in release 5.2, have been removed (see below detailed list of changes).

An enumerator of step limitation algorithms of the multiple-scattering process has been introduced. It replaces a boolean value . The step limitation types are: As in releases 8.0 to 8.2, the minimal option (which used to be called 'no step limitation') results in fewer steps, and typically provides less stability than the other options.

Hadronic physics

Physics Lists

Removed physics lists LHEP_HP, QGSP_HP, LHEP_BIC, LHEP_BIC_HP and LHEP_PRECO, which were marked obsolete in release 8.2. Users are encouraged to evaluate QGSP_BIC as a replacement of LHEP_PRECO and LHEP_BIC. The list LHEP_BIC_HP is replaced by QGSP_BIC_HP. In place of the remaining lists (LHEP_HP, QGSP_HP) we suggest to evaluate QGSP_BERT_HP and QGSP_BIC_HP.
Also removed physics lists using the Mars13 leading particle classes, i.e. lists with a name containing _LEAD_.

The components for electro-magnetic physics have been renamed and three variants are now available:

Data Sets

This release introduced three new versions of the following data sets. Please see the last section for the corresponding details.

4. New Developments and Capabilities

Error Propagation Standard Electromagnetic physics Hadronic physics: Neutrons

5. Expected effects on physics and performance

Standard Electromagnetic physics Hadronic physics

6. Known Run-Time Problems and Limitations

For a complete list of outstanding run-time problems and to submit any problem you may find running this version of Geant4, please refer to the Geant4 Problem Reporting System.

7. Compilation Warnings

There are compilation warnings on some tested platforms. We do not believe that any of these lead to incorrect run-time behaviour.

8. Known Run-Time Warnings

The following message can be written to standard output at the end of a program:
    G4Transportation: Statistics for looping particles 
       Sum of energy of loopers killed: 
       Max energy of loopers killed: 
It provides the total energy (in MeV) of tracks killed due to excessive number of steps ('looping') during the simulation, and the maximum energy of such a track. Such behaviour can be due to looping in magnetic fields or encountering problems at geometrical boundaries.

In case either of these reported energy is significant, we recommend to increase the verbosity of G4Transportation to obtain information for each track killed. A user can change the threshold energy above which particles are not killed using the method SetThresholdImportantEnergy of G4Transportation. The default value is 250 MeV.

9. Geant4 Software License

A Software License applies to the Geant4 code. Users must accept this license in order to use it. The details and the list of copyright holders is available at and also in the text file LICENSE distributed with the source code.

10. Detailed list of changes and fixes

These are the main new features/fixes included in this release since the last patched public release (for more detailed lists of fixes/additions, please refer to the corresponding History files provided in most packages):


Digitization & Hits

Electromagnetic Processes

Error Propagation


General Processes



Graphical Representations

Hadronic Processes




Physics lists


Track & Tracking



Data sets