Re: Isotope in beam card

From: Francesco Cerutti <>
Date: Wed, 10 Aug 2011 17:39:03 +0200

Dear Sunil,

the problem you met is related to your USRTRACK scoring and in particular
to the requested energy range, which turns out to be ... from zero to
zero, as you can read in the output file:

linear energy binning from 0.0000E+00 to 0.0000E+00 GeV, 10 bins (
0.0000E+00 GeV wide)

This of course makes no sense and, due to the bin size of zero, leads the
code to crash.

Since you missed the USRTRACK continuation line, the default energy range
applies, normally extending for linear binning from zero to the beam
energy. However, for an ISOTOPE, an energy different from zero cannot be
accepted and is reset to zero, as again documented in the output file:

!!! An energy/momentum different from zero makes no sense for a
(radioactive) isotope "beam"

In the end, just specify a suitable max scoring energy for your decay
photons and you will see their spectrum



Francesco Cerutti
CH-1211 Geneva 23
tel. ++41 22 7678962
fax ++41 22 7668854

On Tue, 9 Aug 2011, Sunil C wrote:

> Hi All
> I remember Francesco's suggestion in the discussion list about using the
> Beam card to simulate a radioactive source.
> ( )
> I was trying such an input (see attachment) and FLUKA crashes with a
floating point exception,
> core dumped message. 
> I could not find any explanation about anything more to be done when
using such a source.
> Can someone see what is missing? 
> Thanks a lot.
> Sunil
Received on Thu Aug 11 2011 - 13:01:21 CEST

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