Re: Heavy ion transport

From: <Andrea.Mairani_at_mi.infn.it>
Date: Wed, 31 Mar 2010 12:27:02 +0200 (CEST)

Dear Ivan,
 as I have already described this topic in the fluka mailing list.
(http://www.fluka.org/web_archive/earchive/new-fluka-discuss/2712.html)
See below:
"The concept of threshold for primary particles is used in the manual just
to remind to the users to use a primary beam energy higher than the
transport threshold in order to simulate a meaningful history.
When we speak about energy threshold we speak about the TRANSPORT energy
threshold and in the case of heavy ions it can be much lower than 10 MeV/n.
The code sets the TRANSPORT energy threshold of Heavy Ions using the alpha
particle one (i.e. keeping the same energy per nucleon).

The transport energy threshold for the alpha particles is set by the
DEFAULTS card and it can be overwritten using the PART-THR card.
For example if you are using the NEW-DEFA default the article transport
threshold is 10 MeV, i.e., 2.5 MeV/n for the alpha particles and for the
heavy ions.
Instead, the energy threshold for nuclear reaction of heavy ions is 100
MeV/n.

"In other words its transport is then calculated only
down to 100MeV/n or down to 10MeV/n?"

Answering your question, the transport is calculated down to the transport
energy threshold (calculated as explained above) while the nuclear
reactions are handled down to 100 MeV/n.

In order to simulate the interactions of ions at energies below 100
MeV/nucleon you need an additional package, the BME generator, that is not
distributed with the standard fluka version. The reason is that it is not
yet fully tested and it is still under development. Users who wish to use
it should be aware that it is still a preliminary version.
If you wish to use the BME, please contact Alfredo.ferrari_at_cern.ch or
francesco.cerutti_at_cern.ch

Ciao
Andrea

> Dear FLUKA Team,
>
> in the FLUKA manual is written, that lower transport limit for heavy
> ions as PRIMARY particles is 100MeV/n and transport limit for heavy ions
> as SECONDARY particles is 10MeV/n. I have one question which relates to
> following example. One simulate the transport of heavy ions with initial
> energy 150 MeV/n through some material. During the transport of some
> primary particle after decreasing its energy let's say to 120 MeV/n an
> inelastic interaction occur. This primary particle looses one or more
> nucleons as a result of the interaction. Now question is if this
> original primary ion is further threated still as a primary or as a
> secondary particle. In other words its transport is then calculated only
> down to 100MeV/n or down to 10MeV/n? Thank you very much for your answer.
>
> Best regards
> Ivan
>
>
Received on Wed Mar 31 2010 - 13:34:40 CEST

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