Since its release in 1999, the LHC experiments have been evaluating GEANT4 in
view of adopting it as a replacement for the obsolescent GEANT3 transport
MonteCarlo. The ALICE collaboration has decided to perform a detailed physics
validation of elementary hadronic processes against experimental data already
used in international benchmarks. In one test, proton interactions on different
nuclear targets have been simulated, and the distribution of outgoing particles
has been compared to data. In a second test, penetration of quasi-monoenergetic
low energy neutrons through a thick shielding has been simulated and again
compared to experimental data. In parallel, an effort has been put on the
integration of GEANT4 in the AliRoot framework. An overview of the present
status of ALICE GEANT4 simulation and the remaining problems will be presented.
This document will describe in detail the results of these tests, together with
the improvements that the GEANT4 team has made to the program as a result of
the feedback received from the ALICE collaboration. We will also describe the
remaining problems that have been communicated to GEANT4 but not yet addressed.Comment: 8 pages, 12 figures, for the CHEP03 conference proceeding