|Message: Re: Cf 252 Neutron Source||Not Logged In (login)|
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On Wed, 20 Jul 2011 03:45:02 GMT, Michael H. Kelsey wrote:
> On Tue, 19 Jul 2011 23:06:05 GMT, Eric wrote: > > > I need to define a Cf 252 neutron source, and haven't been successful. > > In previous sims, I've been dealing mostly with monoenergetic things > > (ie, Cs137, I would just define a 662 kev gamma and call it good), but > > there should be a range of values for Cf 252. > > > > I've defined the source using something like: > > ---------------------------------------------------- > > particleGun->SetParticleEnergy(some value*eV); > > particleGun-> SetParticlePosition(G4ThreeVector(0.,0.,0); > > particleGun->SetParticleMomentumDirection(G4ThreeVector(0.,0.,1)); > > > > G4int Z=98, A=252; > > G4double ionCharge = 1.*eplus; > > G4double excitEnergy= 0.*keV; > > > > G4ParticleDefinition* ion = > > G4ParticleTable::GetParticleTable()->GetIon(Z,A,excitEnergy); > > particleGun->SetParticleDefinition(ion); > > particleGun->SetParticleCharge(ionCharge); > > > > particleGun-> GeneratePrimaryVertex(anEvent); > > ---------------------------------------------------- > > > > Which gives me an ion, in the simulation, of Cf252, but doesn't emit a > > range of low energy neutrons. I haven't found a good example showing how > > to do this... anyone have any insight? > > Take a look at examples/extended/radioactivedecay/rdecay01. You need to > have included G4RadioactiveDecay in your PhysicsList, and you need to > enable it for your geometry (either all volumes or just your source).
Well, I'm now suitably embarrassed :-( This week, I've started working with a Cf-252 source in my own simulation, and the advice I gave you won't work, at least not in GEANT4 9.4. With |/grdm/verbose 1|, I get the following message:
G4RadioactiveDecay::DecayIt : Cf252[0.0] is not a valid nucleus for the RDM
So apparently in 9.4 RDM doesn't know how to deal with spontaneous fission and neutron emission. I will inquire further with the experts and see if this is going to be resolved in 9.5.
-- Michael Kelsey
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