Re: [VMC] VMC: hadronic interactions with ions

From: Ivana Hrivnacova (Ivana.Hrivnacova@cern.ch)
Date: Thu Dec 18 2003 - 11:12:36 MET


 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
> **************************
> 
> 
> 

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