Description
GATE/Geant4 enters an infinite loop when using the emstandard_opt4 physics list for voxelized phantoms. An infinite number of steps with step length 0 and dE 0 is produced (see tracking output below). Geant4 does not detect the stuck particle and does not try to force push it, as it typically does to unstuck particles.
Log output:
[...]
- G4Track Information: Particle = e-, Track ID = 3, Parent ID = 1
Step# X(mm) Y(mm) Z(mm) KinE(MeV) dE(MeV) StepLeng TrackLeng NextVolume ProcName
0 -9.69 2.08 -1.83 0.237 0 0 0 test_voxel_phys_Z initStep
1 -9.86 2.05 -1.8 0.229 0.00721 0.18 0.18 test_voxel_phys_Z msc
2 -10 2.03 -1.77 0.216 0.0133 0.142 0.322 test_voxel_phys_Z msc
3 -10 2.03 -1.77 0.216 3.5e-06 0.00128 0.323 test_voxel_phys_Z msc
4 -10 2.03 -1.77 0.216 8.8e-05 0.00336 0.326 test_voxel_phys_Z Transportation
5 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
6 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
7 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
8 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
9 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
10 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
11 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
12 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
13 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
14 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
15 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
16 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
17 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
18 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
19 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
20 -10 2.03 -1.77 0.216 0 0 0.326 test_voxel_phys_Z eIoni
[...]
- OS: Ubuntu 20.04
- Gate version: v9.3
- Geant4 version: v11.1.2
- Root version: v6-29-01
- Compiler version: gcc 9.3.0 (from the 9.3.0-1ubuntu2 deb package)
- Physics list: emstandard_opt4
The issue is gone when switching to the emstandard_opt3 physics list. I cannot reproduce this issue with GATE v9.1 and Geant4 v10.7.2, so it seems to be a recent regression.
I'm currently not sure if this issue is related to GATE or rather Geant4 itself. I will investigate further.
A minimal working example is available here: minimal_working_example.zip. Please be prepared to kill the process before running the example, as the vast amount of Hits produced in the infinite loop quickly eats up memory.