| Summary: | Sharp peaks at 1 keV and 100 keV in neutron spectrum in LEP model | ||
|---|---|---|---|
| Product: | Geant4 | Reporter: | dennis.herbert.wright |
| Component: | processes/hadronic/util | Assignee: | Hans-Peter.Wellisch |
| Status: | RESOLVED WONTFIX | ||
| Severity: | normal | ||
| Priority: | P2 | ||
| Version: | 7.0 | ||
| Hardware: | All | ||
| OS: | All | ||
this is an intended model feature. It is usefull that the line shows up. It is indicating that if this area of energies in relevant to a user, the model is not appropriate. Many greetings, Hans-Peter. |
Reported by LHCb and verified by D.H. Wright, there are two sharp peaks in the neutron spectrum, a large one at 1 keV and a small one at 100 keV. These are due to negative energy protections in G4ReactionDynamics::TwoBody and G4ReactionDynamics::Rotate. The code lines causing the problem look like ekin = std::max( 1.0e-6, ekin ); Changing this to ekin = std::max(0.0, ekin ); for lines 2492 and 2501 in TwoBody removes the 100 keV line and for lines 3007, 3036, 3067, 3108, 3127, 3147 in Rotate removes the 1 keV line.