|Message: particleHP: missing Doppler brodening for neutrons?||Not Logged In (login)|
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for a medical application I am trying to simulate emission profils of prompt gamma lines along a path of a ~50-230 MeV proton beam in different target materials such as plexiglas, water,... So far I noticed, that there is a huge difference as far as concerning the physics moduls one choses (f.i. BIC/BERT). Besides that, I found, that the particle HP modul seems to not consider Doppler brodening effects for in-flight-emitted gamma rays in most of the neutron-induced nuclear reactions. To verify this, I simplyfied the problem to a carbon target and looked at one specific gamma line (4.438 MeV). The are only four reactions leading to a gamma de-excitation for this energy (secondary neutrons come from fragmentation):
(1) p + C12 --> p + C12*
(2) p + C13 --> p + n + C12*
(3) n + C12 --> n + C12*
(4) n + C13 --> n + n + C12*
On a stepping base I filtered for these reactions and filled 2d histograms with the kinetic energy of the C12* nucleus on the y-axis and the emitted gamma ray energies from those nuclei on the x-axis. There is also one plot attached with the whole gamma spectrum. These results I get for the QGSP_BIC_HP_EMZ physics list simulated with version 10.3.p01. As I stated, one can see, that for most of the (3)-typ reactions Doppler broadening does not seem to be considered whereas for the other reactions everything looks fine. Do you have any idea if this is a bug or whether my local setting are wrong?
Attachment: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2018/02/02/10.16-19933-Gamma_Spectrum_Ekin.png http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2018/02/02/10.17-60145-ctrum_Ekin_p_C12_4440.png http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2018/02/02/10.17-79062-ctrum_Ekin_p_C13_4440.png http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2018/02/02/10.17-54252-ctrum_Ekin_n_C12_4440.png http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2018/02/02/10.17-48071-ctrum_Ekin_n_C13_4440.png
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