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Forum: Hadronic Processes
Re: None Photonuclear with Bertini in g4.10.00.p01 (Dario Lattuada)
Re: None Re: Photonuclear with Bertini in g4.10.00.p01 (Dennis H. Wright)
Date: 21 Jul, 2014
From: Dario Lattuada <Dario Lattuada>

On Fri, 18 Jul 2014 17:45:16 GMT, Dennis H. Wright wrote:
> Hi Dario,
> 
>   I don't think you're doing anything wrong.  The main problem is that the model
> was designed for higher energies, so the fact that it works at, say 20 MeV, is
> fortuitous. At such energies the cascade stage is skipped and the Bertini version
> of precompound and evaporation models take over.  In that case, alpha
> emission is rare until about 20 MeV as you have seen.
>   You might want to try an alternative precompound model.  You can do this with the lines
> 
> G4CascadeInterface* theCascade = new G4CascadeInterface();
> 
> theCascade->usePreCompoundDeexcitation();
> 
> in your physics list. This invokes the Geant4 standard deexcitation
> code,
> 
> which is slower, but has code dedicated to nuclear breakup and thus may
> do a better job for you.
> 
> Dennis
> 

Hi and thank you for your reply.

I just did as you suggested and here are the alphas! It wasn't much slower and I'm checking the results right now but it is a huge step forward. Thank you again.

Maybe it could be a good idea to put a note on the manual to explicitly discourage (novice) people from using bertini cascade below its range of validation (below 100MeV) and to suggest the use of other methods in its place.

On a (almost) side note, could you please tell me where I can find further documentation on G4PhotoNuclearCrossSection? If I'm not wrong, it holds the cross sections of the photonuclear process (high and low energy values are separated in different sets) but I assume that for just-above-threshold energy the values are calculated using a linear fit (at best) from GDR values to the first bin and there are not complicated calculation implemented (Hauser-Feshbach or others), which is something we could (and some people would be pleased to) add without much work, I guess. Well, I might be completely wrong on that, so that's why I'm asking for some specific info about it.

Anyway, thank you (it's third one in same message, sorry). Dario

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1 None: Re: Photonuclear with Bertini in g4.10.00.p01   (Dario Lattuada - 25 Jul, 2014)
(_ None: Re: Photonuclear with Bertini in g4.10.00.p01   (Michael H. Kelsey - 25 Jul, 2014)
(_ None: Re: Photonuclear with Bertini in g4.10.00.p01   (Dario Lattuada - 29 Jul, 2014)
1 None: Re: Photonuclear with Bertini in g4.10.00.p01 (ERRATA CORRIGE)   (Dario Lattuada - 29 Jul, 2014)
2 None: Re: Photonuclear with Bertini in g4.10.00.p01   (Dennis H. Wright - 31 Jul, 2014)
1 None: Re: Photonuclear with Bertini in g4.10.00.p01   (Dario Lattuada - 01 Aug, 2014)
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