GEANT4 Low-Energy Compton Scattering Package

UPDATE --- Dec-2008

As of GEANT4.9.2 the G4LowEnergyCompton physics process includes a treatment of Doppler broadening very similar to that provided by G4LECS. Furthermore, errors in G4LowEnergyRayleigh have been resolved. The new G4LowEnergy processes have been compared to G4LECS and found to be very similar in terms of results and computing speed (see test results). It is, therefore, suggested that users of G4LECS migrate to the G4LowEnergy packages for best long-term maintainence. This web site will be maintained, but the G4LECS code will be frozen at version 1.07.

G4LECS is an extension program for the GEANT4 simulation package that incorporates detailed physics into the simulation of Compton and Rayleigh scattering. In standard GEANT4, the free electron approximation is used for Compton scattering, and Rayleigh scattering is ignored. The G4LowEnergy extension package included in the GEANT4 distribution corrects the Compton cross sections and for bound electron momentum, but does not account for the resulting changes in the scattered particle energies (known as Doppler broadening). Furthermore, there are errors in the treatment of Rayleigh scattering.

These problems lead to significant errors in simulating photon scattering at energies near/below several hundred keV. The G4LECS treatment of Compton scattering accounts for bound electron momentum on a shell-by-shell basis using evaluated data read from tables. For Rayleigh scattering, G4LECS uses evaluated coherent scattering cross section and form factor data read from tables.

G4LECS was designed to be used transparently with any GEANT4 application. It is particularly useful for simulating advanced Compton telescopes, where the fine position and energy resolution make the inclusion of Doppler broadening crucial for realistic simulations. For more details and installation instructions see the README file below.

Note the the present release of G4LECS does NOT account for the polarization-dependence of the scatter angle distributions. A future release of G4LECS will include polarization effects.


View the README file Download/Version Compatibility


View paper about GLECS (New Astronomy, 2004) View a test report about GLECS (from Elena Novikova, NRL)


View test results


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Author: R. Marc Kippen
Last modified: 23-Dec-2009