|Message: Re: (n, n+alpha) reaction at 16Oxygen, NeutronHP, G4.10.00||Not Logged In (login)|
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On Wed, 09 Apr 2014 18:22:34 GMT, bbv_nsk wrote:
> Colleagues, I am considering a model with pure Oxygen and 14 MeV neutron > source. I use the Geant4.10.00. Using tracking verbosity I look at the > secondary particles emitted after inelastic reactions. Specifically I am > interested in the reaction (n, n+alpha). > > I see that after each such reaction one gamma particle with the energy > 4.44 MeV is always emitted. And I have a concern here. > > The emission of gamma particles after such reactions is described in the > ENDF VII data library with two sets of cross sections. The first set is > the neutron cross section data and they are given by MF = 3 and MT = 22. > The second set is the photon production cross sections data that are > given by MF = 13 and MT = 22. These two sets of data should be used for > computing the multiplicity of emitted gamma particles by taking a ratio > of the production cross sections to the neutron cross sections. > > I see that the multiplicity of emitting the gamma quantum with the > energy 4.44 MeV is less than unity but the Geant4 acts like it is equal > to unity. > > I looked into the source code and I didn't see that the multiplicity are > calculated. I think there is a problem in this part of code. > > Could you please comment this issue? > > Thanks, Bair >
Here is a run of example Hadr03 with attached macro. Also output, gamma spectrum and zoom of 4-5 MeV region. As you can see, there is 19321 (n, n+alpha) reactions. Number of gamma 4.44 MeV is about 10000
I do not know if these numbers are compatible with ENDF VII
Attachment: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2014/04/12/07.49-69804-neutron.mac.txt http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2014/04/12/07.49-1737-output.txt http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2014/04/12/07.49-87136-gamma.gif http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2014/04/12/07.49-93905-zoom.gif
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