Dear colleagues! A problem has arisen related to modeling the passage of positrons through a tungsten moderator. The main problem is that theoretically positrons should come out with an energy of several eV (~0.05% of the total flux falling on the moderator). Due to my inexperience, I would like to ask whether it is possible to implement this in Geant4?
Dear @Stephan_Korneev,
Welcome to the Geant4 forum!
In general, Geant4’s electromagnetic models for electrons and positrons work well down to about 1 keV. Below that energy, other models or data are needed.
EM physics list option 4 [1] provides more detailed models for e+/- transport, could you please try it out? It might be sufficient for your case.
Could you please comment on the title of this thread, “Negative Work Function for positrons in tungsten moderator”?
It might be possible to add such low-energy models, but I’ll let the experts @mnovak and @civanch comment on that.
Best,
Alvaro
[1] EM Opt4 — PhysicsListGuide 11.3 documentation
Dear atolosad,
thank you so much for your reply! I`ll try to implement the EmOp4, than, hope, it might work. I do not know, whether it reasonable to add such a model directly in Geant4. The principle of negative work function for positrons is introduced in the same way as it is explained for electrons. However, in the case of positrons, this work function, to put it simply, acts as an accelerating potential, allowing thermolyzed positrons to leave the surface of metals. I have had a lot of difficulties with this, since I can’t figure out how to implement this in Geant4 and whether it is possible in principle.
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