Right,
what happens is fundamentally NOTHING, in the sense that GEANT3 does not
model hadronic interactions of ions *at all*. I am surprised you see any
hadronic interaction for everything with A>1. The latest version of FLUKA
handles ion interactions, but this is not yet completely interafaced with
the VMC. Fed
On Thu, 18 Dec 2003, Ivana Hrivnacova wrote:
>
> Hi Paolo,
>
> I will only explain what does Geant3 VMC
> when you call gMC->DefineIon(..) in your
> VMC application class:
>
> gMC->DefineIon(...) adds a geant3 particle via
> Gstpart(...) function with setting the ITRTYP code
> (type of tracking routine) to ITRTYP=8.
> Then this particle definition is also added to TDatabasePDG
> (if it does not yet exist here) and mapped to the geant3
> particle id.
>
> What happens next is a question for Geant3 experts.
>
> Regards,
>
> Ivana
>
> ==============================================================
> e-mail: Ivana.Hrivnacova@cern.ch
> address: Institut Physique Nucleaire, 91406 Orsay, France
> phone: (33) 01 69 15 65 94
> ==============================================================
>
> On Tue, 16 Dec 2003, paolo maestro wrote:
>
> > Hi,
> > I defined in the method AddParticles of my class
> > inheriting from TVirtualMCApplication some ions through:
> >
> > gMC->DefineIons("He4",2, 4, 2, 0, 3.75309);
> > gMC->DefineIons("Li6",3, 6, 3,0 , 5.62963);
> > gMC->DefineIons("B10",5, 10, 5,0 , 9.38272);
> > and so on.
> > Then I switched off the hadrons interaction in geant3
> > by selecting the FLUKA generator.
> > In my application I have a calorimeter
> > preceeded by a carbon target acting as a pre-shower .
> > I noticed that when I run with protons or nuclei as D, He up to Li6
> > the hadronic cascades occur with a rate according to the total number of
> > interaction
> > lengths of my detector.
> > But with heavier nuclei (starting from B10) the hadronic interactions
> > seem to be switched off
> > and nuclei pass through the calorimeter as minimum ionizing particles.
> > The situation is even worse by using the geisha generator. Infact in
> > this case all the nuclei behave as mips.
> > Which is the reason of these behaviours ?
> > Is it due to some limitation of the fluka/geisha generator inside
> > geant3?
> > Or do I have to do something else to run properly with ions?
> > Thanks.
> > Best regards
> > Paolo
> >
> >
> > **************************
> > Paolo Maestro
> > Universita' di Siena-INFN
> > Phone ++39-050-2214349
> > Fax ++39-050-2214317
> > **************************
> >
> >
> >
>
>
--
Federico Carminati
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