Re: about angular distribution

From: Giuseppe Battistoni <>
Date: Mon, 30 Mar 2009 16:12:02 +0200 (CEST)

Dear Emilia,
First of all I wonder if fluence distribution has to be used instead of
Second: a divergence defined in this way is independent of energy.
I do not know the details of your problem, but in general there
could exist correlations between energy and angle.
The best way, in my opinion, to address your need would be to build
a user source routine in which you program the sampling of a double
differential distriution which you will derive from the USRBDX
output of the first simulation.

Some users already did that succeffuly. I invite them to share
such tools and results

        Giuseppe Battistoni

On Tue, 24 Mar 2009, Emilia Basile wrote:

> Dear Fluka developers and users,
> thanks for clearing up my previous questions.
> Now, I've another question about USRBDX results.
> I've to use the results of output parametrization for a new input file,
> and I've some doubts about the beam divergence.
> I requested in input the current distribution across a plane which is
> perpendicular to the beam direction.
> Integrating the double differential current distribution over the
> energy, I should get current distribution in theta, where theta is
> related to the solid angle omega by means:
> theta=2 arcsin(omega/4 pi)^0,5
> Fitting the current distribution in theta with a Gaussian function, I get
> the FWHM of the Gaussian angular distribution. Is it correct writing it in
> the input file as new beam divergence?
> Thanks in advance,
> Emilia
Received on Mon Mar 30 2009 - 16:52:03 CEST

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