|Message: Re: Neutron Range||Not Logged In (login)|
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On Tue, 12 Dec 2017 12:19:37 GMT, michel maire wrote:
> > As you know, for neutrons, elastic collisions are important (even dominant at thermal energies), making trajectories of such neutrons erratic. > > For example, from Hadr03 I read : neutrons 10 MeV on Gd, mean free path for elastic collisions ~ 13 cm and inelastic interactions ~ 13 cm (a coincidence !). > A neutron can make several elastic collisions before to end with an inelastic interaction. > To see the effect, you may run Hadr04 or Hadr07 interactively with visualisation, with attached macros. > Defining "range" or "penetration" of neutrons is not so simple as for charged particles : there is no Bethe Bloch formula ! > > Ps : Hadr04 is exclusively devoted to neutrons. It does not make sense to shoot a proton. > > Attachment: > http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/12/12/04.14-45606-hadr04.mac.txt > http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/12/12/04.14-91482-hadr07.mac.txt >
Dear Dr. Marie,
Thank you so much for your consideration. I am grateful for your reply and teaching efforts. Using a proton in a Hadr example was just because of curiosity and I was trying to make it clear for me.
On the other hand, I tried to run the macros you provide. As you already mentioned, visual observation makes it more clear for understanding yet I still aspire to obtain the neutron and gamma ranges in materials. It is clear that Bethe-Bloch formula is valid for charged particles. Also, you indicate range or penetration definitions are not so simple for neutral particles, I also get that. However, there must be a method for obtaining these values. I am sure Geant4 is capable of doing that. I just do not know how to use it. I will be so grateful if you could point a direction for me.
Respects, M Sek
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