| Summary: | Unphysical time for particles in shower | ||
|---|---|---|---|
| Product: | Geant4 | Reporter: | John Apostolakis <John.Apostolakis> |
| Component: | track | Assignee: | kurasige |
| Status: | RESOLVED FIXED | ||
| Severity: | major | CC: | kurasige, morozovs, soldner |
| Priority: | P2 | ||
| Version: | 9.5 | ||
| Hardware: | PC | ||
| OS: | Linux | ||
| Attachments: | Slides on time differences between G4 9.4p3 and 9.5p1 | ||
|
Description
John Apostolakis
2012-04-17 10:48:23 CEST
I received an email report from Christian Soldner (CALICE) about a problem with timing of hits: Dear Colleagues and GEANT4 development team! In my current studies of the timing of energy depositions within hadronic showers I noticed something strange: Using GEANT4.9.5.p01 I observed calorimeter hits occurring earlier than the time of flight would allow. Switching to GEANT4.9.4.p03 those hits are not present. You can find details on this in the slides I attached to this mail. [JA: I am seeking permission to attach these slides. ] For now we will I stick with 4.9.4.p03, but I hope the GEANT team can reproduce and look into this issue. Created attachment 159 [details]
Slides on time differences between G4 9.4p3 and 9.5p1
Christian confirmed that the problem appears with three different physics lists: QBBC, QGSP_BERT_HP and LHEP In particular, in order to be sure that the problem is not related to the slow neutron tracking, he tried LHEP The same effect is visible in all physics lists. ( It can be seen in the slides, in the title of the respective plots. ) A bug in G4PaticleChange::AddSecondary causes the problem. The local time of the parent track was set to secondaries instead of global time. This G4ParticleChange::AddSecondary is used only by hadronic processes. So, tracks created by hadronic interaction of secondary particles from incident muon have wrong timing. I've committed the bug fixed tag of track-V09-05-06. *** Problem 1344 has been marked as a duplicate of this problem. *** |