Re: A question about usrbdx_21_sum.lis

From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Wed, 8 Oct 2008 16:50:34 +0200 (CEST)

Dear Yuanjie Bi
the explaination is in the different normalizatiom
the fluxes (Part/sr/GeV/cmq/pr) are the flux per unit of solid angle,
while the fluxes (Part/deg/GeV/cmq/pr) are per unit of "linear" angular
interval. There is a factor roughly proportional to
   d(cos(theta)) = sin(theta) between the two, that builds a hole at theta~0
Regards
Paola
> Dear fluka users,
>
> I calculate the angular distribution of protons after they pass through a
> very
> thin carbon foil.
> The initial beam is monochromatic, monodirectional proton beam of
> momentum 100
> MeV/c.
> The result is given in 'usrbdx_21_sum.lis'.
>
> The double diff. fluxes expressed as 'Flux (Part/sr/GeV/cmq/pr)' have the
> maximum
> at the 1st Solid angle bin, which is the expectant result. But the double
> diff.
> fluxes expressed as 'Flux (Part/deg/GeV/cmq/pr)' have the maximum at the
> fifth
> angular bin, I cann't understand this. I hope someone can give me an
> explanation.
>
> Many thanks for your help
>
> ====================================================================
> Best regards
>
> Yuanjie Bi
> BRIF Cyclotron
> CIAE
>
>
>

Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
Received on Wed Oct 08 2008 - 16:59:25 CEST

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