# Re: questions with source & USRBIN

From: Alfredo Ferrari (alfredo.ferrari@cern.ch)
Date: Tue Mar 20 2007 - 12:40:04 CET

• Next message: Serge Denisov: "heavy ion interactions?"

Hi

do you really want to generate cosmic rays pointing inside, that is to the
center of the sphere? If so Mario already explained how to do, however
such a source would be not physical (infinite fluence in the center).
If actually you want to generate a uniform and isotropic fluence inside
the sphere, you can exploit the sflood routine of Fluka.

This subroutine

SUBROUTINE SFLOOD ( XXX, YYY, ZZZ, UXXX, VYYY, WZZZ )

returns in XXX, YYY, ZZZ a random position ON the surface of a sphere
of radius 1 and center 0 (multiply XXX, YYY, ZZZ by the actual radius
and add the center coordinates) and UXXX, VYYY, WZZZ are radnom cosines
properly distributed so that to generate an uniform and isotropic
fluence inside the sphere (of course in absence of material inside the
sphere), numerically given by 1 / (pi R^2), R being the sphere radius.

Ciao
Alfredo
On Sat, 17 Mar 2007, hamide jalali wrote:

> Dear FLUKA users
>
> I want to calculate dose in a spacecraft which is in space so I need to
> simulate a source emitting from a spherical surface in a direction which
> points inside (cosmic ray).Is there any possibility in FLUKA to do this?
> I have modified a source.f(which is in attachment) before for my purpose but
> the results are not logical.please guide me what the problem is.
> And two other questions:
> 1- How can I consider spherical binning in USRBIN?
> 2-Is it necessary to use USRBIN with what(1)=2 to get the same results from
> SCORE and USRBIN?
>
> Any help will be appreciated in advance.
>
> regards
> Hamide
>
> PS the source.f which is in attachment is just for Alpha.I used the same
> ones for other elements of cosmic ray then added up all results to get total
> dose.
>

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|  Alfredo Ferrari                ||  Tel.: +41.22.767.6119                  |
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• Next message: Serge Denisov: "heavy ion interactions?"

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