|Message: Re: results very sensitive to step size||Not Logged In (login)|
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On Fri, 12 Nov 2010 19:31:45 GMT, Cristian Bungau wrote:
> Dear all, > > I am simulating the interactions of 800 MeV protons with a thin (10 mm) > graphite target. I am interested in the (very) rare events when positive > pions decay at rest inside the target. I was advised to run these > simulations with reduced step size to ensure that the Delta E is small > as it could be that the cross section is not adjusted for the end-point > energy value. > > However it turns out that the smaller I force the step size to be, the > more positive pions decays at rest I get, as there are more and more > proton interactions inside the target. I already went down to 100 > micrometers step size limit. So my question is: is there an optimum > value for the step size being given the proton energy of 800 MeV and the > target thickness of 10 mm, or should I be running the simulations with > no step limitations? > > Thank you very much, > > Best regards, > > Cristian >
Inelastic interaction of proton must be independant of step size ! In your situation, it must be enough to run without step limitation. It is hard to believe your result.
As Vladimir asked, how do you count inelastic interaction ? and how do you control step size ? Is there something special in your physics list ?
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