Re: dpdx=<0 problem in isotope user written source simulation

From: Alfredo Ferrari <alfredo.ferrari_at_cern.ch>
Date: Tue, 7 Sep 2010 11:37:16 +0200

Dear Ogawa

your mistake is to use "ISOTOPE" instead of "HEAVYION" in the beam card.
ISOTOPE means radioactive decays from the given isotope, that is the
code generates the gammas/beta+/- corresponding to the decay of the
given isotope. In this case the maximum energy is hardwired in FLUKA
to few hundreds of MeV (well enough of course) and WHAT(1) is ignored.
Indeed the code should have warned you, writing in the output file (please
check):

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

Change ISOTOPE into HEAVYION, set what(1) to a resonable value (it
is the energy per nucleon of the isotope defined by HI-PROPE), too large
values wrt your actual needs only waste memory and accuracy.

                 Ciao!
                Alfredo

+----------------------------------------------------------------------+
| Alfredo Ferrari || Tel.: +41.22.76.76119 |
| CERN-EN/STI || Fax.: +41.22.76.69474 |
| 1211 Geneva 23 || e-mail: Alfredo.Ferrari_at_cern.ch |
| Switzerland || |
+----------------------------------------------------------------------+

On Thu, 2 Sep 2010, Ogawa Tatsuhiko wrote:

> Dear FLUKA experts,
>
> I am trying to transport isotopes using a user written source. But I
> don't know why it crashes saying
>
> Stepop, dp/dx=<0!! ij, z, a, mmat, ekin, pthrmx, dpdx0 -2 23 49 6 0.6
> 7.80517436 -543.194742
> Abort called from STEPOP reason dp/dx=<0 Run stopped!
> STOP dp/dx=<0
>
> in .err file.
>
> This happened regardless of WHAT(1) of BEAM card.
> It seems to have something to do with source energy because when I
> overwrite source kinetic energy (for example 18.1824493218291 -> 0.50),
> it runs.
>
> I would appreciate if someone could help me to run this simulation.
>
>
> Please find the attached files if necessary.
>
> coll.inp: input file
> source_frag.f: modified source.f file. Source file directory is defined
> in the 71st line.
> iso-source.dat: source information. the columns are atomic number, mass
> number, x,y,z coordinates, x,y,z angular cosines, kinetic energy (not
> divided by the number of nucleons), statistical weight, respectively
> from left to right.
>
> Many thanks in advance,
> Ogawa
>
> --
> **************************************************
> Department of Nuclear Engineering and Management
> Graduate School of Engineering
> The University of Tokyo
>
>
> Tatsuhiko Ogawa
> E-mail: ogawa_at_n.t.u-tokyo.ac.jp
> togawa_at_cern.ch
> Tel: 090-9241-4166 (+81-90-9241-4166)
> 03-5841-2905 (+81-3-5841-2905)
> Facsimile: 03-3813-2010 (+81-3-3813-2010)
> Address: 2-11-16, Dept. Nucl. Eng. Annex R-230
> Yayoi Bunkyo-ku, Tokyo 113-0032
> **************************************************
>
Received on Tue Sep 07 2010 - 16:01:21 CEST

This archive was generated by hypermail 2.2.0 : Tue Sep 07 2010 - 16:01:21 CEST