| Summary: | Wrong cross-sections in gamma-nuclear model in Geant4.10.07 (beta) | ||
|---|---|---|---|
| Product: | Geant4 | Reporter: | Aleksei <dinAlt220> |
| Component: | processes/hadronic/cross_sections | Assignee: | dennis.herbert.wright |
| Status: | RESOLVED MOVED | ||
| Severity: | major | ||
| Priority: | P4 | ||
| Version: | other | ||
| Hardware: | All | ||
| OS: | All | ||
| Attachments: | CS_Au197(g,n) | ||
Was it OK in Geant4 10.6 ? (In reply to dennis.herbert.wright from comment #1) > Was it OK in Geant4 10.6 ? The thing is that the production of metastable levels from photons is only available in geant4.10.07 version. In earlier version there was no such function. In 10.7 beta we changed the way low energy gammas are modeled. We now use the G4Precompound model, so I checked with Vladimir Ivantchencko, who maintains that model. Here is what he says: "There is the only one (but important) modification in 10.7beta: for gamma low-energy model below 200 MeV is used. This model is fully based on pre-compound model. I have added this but we need to test the effect. What is the difference: in Bertini by default nuclear levels are not used, so lines cannot be produced. Probabilities of metastable levels depend on probabilities of transitions, so in the new version we have levels but we do not know how accurate is the cross section, which depend on many factors. I event not sure that 200 MeV is the optimal limit – likely this should be reduced. We may now add native de-excitation for Bertini. So there are possible tuning of configuration and in models. In order to improve something in this area we need to have some set of tests. It is a critical point now." So some work is needed in this area. We'll move this into development and hopefully it will be fixed by the time of the full release in December. |
Created attachment 633 [details] CS_Au197(g,n) Dear developers, I noticed that cross sections for photo nuclear reactions in the new version of Geant4.10.07 are not ok. I investigated the reaction Au197(g,n)Au196 by means of Hadr03 example using QGSP_BIC physics list and G4RadioactiveDecayPhysics. As you could see there is a problem (please look at the image attached). The CS for Au196m1 is much higher than for Au196_ground. And that is not right. Also I saw the same situation for production of Hg197m through (p,n) reaction...