From: Francesco Cerutti (Francesco.Cerutti@cern.ch)
Date: Thu Mar 22 2007 - 19:49:44 CET
> i used rqmd for the heavy ion energies around 20MeV/nucleon in my
> former simulations. the results well agreed on with low Z heavy ions
> like Ne, Ar while it was not agreed on with high Z heavy ions like Xe.
> the results i meant agreed on with was with s/trim, g3 and g4. so am i
> mistaken by simulations now? or should just i consider again for high
> Z value ions with bme options?
you are confusing INELASTIC INTERACTIONS and TRANSPORT.
Rqmd is meant to describe nucleus-nucleus reactions (producing in general
light particles and heavier residues) for incident energies between 5
GeV/n and 100 MeV/n. You can adjust the lower threshold (not
recommended) resetting it in the WHAT(3) of the PHYSICS card with SDUM =
DPMTHRES, nevertheless the code does not allow you to use Rqmd below 50
MeV/n (whatever lower value you put it is assumed to be 50 MeV/n).
This means that for a heavy ion beam at 20 MeV/n you are not at all using
Rqmd and inelastic nucleus-nucleus interactions are not performed
(conversely nucleus-proton reactions are). They will be treated by the BME
event generator as soon as it will be included into the release.
On the other hand, the transport of heavy ions (implying ionization) is
performed down to much lower energies and its reliability looks fine also
for high Z (see http://www.fluka.org/references/talks/aro-10.html, slide
96; A. Ferrari, J. Ranft, P.R. Sala, The FLUKA radiation transport code
and its use for space problems, invited talk at the 1st International
Workshop on Space Radiation Research and 11th Annual NASA Space Radiation
Health Investigators' Workshop, Arona, May 27-31 2000, Physica Medica, XVII,
Suppl. 1, p. 72-80, 2001).
However, your "complaints" about the high Z ion stopping power are
perfectly founded: they allowed to discover a bug and fix it. An updated
version (fixing in addition the lattice problem discussed at
point 2) should be released in a few hours.
Ciao (and thanks!)
CH-1211 Geneva 23
tel. ++41 22 7678962
fax ++41 22 7668854
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