Re: how to kill electrons exiting the target

From: Stefan Roesler <>
Date: Sun, 8 May 2011 10:39:43 +0200

Dear Francesca

I suggest that you use the user routine usrmed.f for that purpose (see
Manual Chapter 13.2.28 for a description. It allows you to set the
particle weights to zero of those particles that you want to kill.

See also


On Fri, 6 May 2011, Fiorini Francesca wrote:

> Dear Fluka users,
> My question could sound a bit un-physical, but I am simulating something
> unusual for Fluka and according to me this is the only way to have some
> reasonable results.
> I have a beam of electrons interacting with a target and as results I
> obtain a beam of photons and electrons exiting the target. I would like
> to kill all the electrons exiting the target, but without killing any
> electrons eventually generated elsewhere (i.e. by interaction of the
> photon beam with something along the beam line). Is this possible?
> I think I cannot use the biasing card, not only because using W(1)=2,
> I would select a bias for electrons, photons and positrons (instead I
> want to kill only electrons), but also because: if I use W(1)>0, i.e. a
> bias in a particular region (in my case the vacuum region outside the
> target), the other regions wouldn't see that I killed the electrons in
> the vacuum region, and if I used W(1)<0, i.e. a bias in all regions,
> this bias would effect also the electrons produced by the photons. Is
> what I've written correct or have I misunderstood the way bias functions
> work?
> The other solutions I could think of would be separating photons and
> electrons directly at the exit of the target, writing a file with the
> characteristics of the photon beam and then using this file as a source
> for the simulation of the other objects along the beam line, but I was
> wondering whether there is a quicker way to obtain the same result.
> Many thanks in advance for any suggestions,
> Francesca
> Francesca Fiorini
> Medical Physics Group,
> School of Physics and Astronomy,
> University of Birmingham,
> Edgbaston Park Road,
> B15 2TT,=20
> Birmingham,
> UK
Received on Sun May 08 2011 - 20:10:29 CEST

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