Problem 1057 - Thermal neutron capture does not generate nuclear lines
Summary: Thermal neutron capture does not generate nuclear lines
Status: RESOLVED FIXED
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/models/neutron_hp (show other problems)
Version: 9.2
Hardware: All All
: P5 major
Assignee: tkoi
URL:
Depends on:
Blocks:
 
Reported: 2009-03-24 22:30 CET by Andreas
Modified: 2009-03-25 02:50 CET (History)
0 users

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Expected result (10.63 KB, image/png)
2009-03-24 22:30 CET, Andreas 		Details
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Description Andreas 2009-03-24 22:30:59 CET 
Created attachment 44 [details]
Expected result

Hello,

I am shooting thermal neutrons (25 eV) on Cd. This results in the reaction 113Cd (n, gamma) 114Cd.
Measurements show that the reaction should lead to a strong 558 keV line, simulations with Geant4.9.2 using the qgsb-bic-hp physics list, don't show any nuclear lines. I tried both cases, once using G4NEUTRONHP_USE_ONLY_PHOTONEVAPORATION and once not.

I was able to trace the problem down to the function G4NeutronHPCapture::ApplyYourself:

The photons in the if-loop starting with "if (HasFSData() ...", both cases, never include the correct nuclear gamma-ray energies and gamma-ray cascades as expected from the photon evaporation data.

Thanks for fixing this problem,
Andreas
Comment 1 Andreas 2009-03-25 00:51:30 CET 
OK. My fault.
I was accidentally using (and debugging) an old Geant4 version. Problem is fixed in version 9.2 using the G4NEUTRONHP_USE_ONLY_PHOTONEVAPORATION flag.
Comment 2 tkoi 2009-03-25 02:50:38 CET 
I also checked independently and “G4NEUTRONHP_USE_ONLY_PHOTONEVAPORATION” flag works fine as designed. I believe this flag also works in previous version of Gean4.
Tatsumi