|Message: Re: NIST Material vs G4Material||Not Logged In (login)|
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On Mon, 23 Apr 2012 16:39:13 GMT, michel maire wrote:
> On Mon, 23 Apr 2012 11:42:46 GMT, J�r�me Roccaz wrote: > > Hi everyone, > > > > I'm using the defined NIST G4_POLYETHYLENE as neutron moderator > > material. As I want to modify this material, I've first tested building > > my own polyethylene with G4Element and using data in Geant4 User's guide > > like this : > > > > density = 0.94*g/cm3; G4Material* PEHDtest = new > > G4Material(name="PEHDtest", density, ncomponents=2); > > PEHDtest->AddElement(elH, fractionmass=0.143711); > > PEHDtest->AddElement(elC, fractionmass=0.856289); > > PEHDtest->GetIonisation()->SetMeanExcitationEnergy(57.4*eV); > > > > When I compare results with both material definitions, they are slightly > > different. Do I miss something in my own definition? > > > Which differences are you speaking about ?
I've buit a PEHD ball in the center of which I have a neutron point source. I print out neutron and gamma spectra in order to calculate dose rate. Dose rate result is different, depending on PEHD definition
> > By default, Nist construtor build isotopes composition, AddElement not (until 9.5) > For hadronic interaction, it could make differences. Not for EM interactions. >
I use hadronic interaction so ... As a conclusion, I should use NIST constructor. As I want to add other element, like boron to my PEHD, I should use both NIST definition for PEHD and Boron and then build the material, right?
By the way, for a gaz mixture like Ar + N2 in ionization chamber, better is to use NIST or G4Element so to have "more realistic" ionization results?
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