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Question low energy deuteron propagation 

Keywords: low energy deuteron propagation
Forum: Physics List
Date: 30 Oct, 2007
From: Abigail Bickley <bickley@nscl.msu.edu>

Dear Experts,

I am trying to simulate the propagation of a 300keV deuteron in a gas
filled volume.  Simple range calculations tell me that the track length
should be approximately 10cm.  However I find that in Geant the tracks
are only ~2cm long.  Is geant capable of reproducing the interactions 
of a deuteron of this energy in a gas?  I've included some specific 
details below.  Suggestions would be appreciated.


Thank you for your advice,

Abby



Physics Processes in PhysicsList:
pmanager->AddProcess(new G4MultipleScattering,-1, 1, 1);
pmanager->AddProcess(new G4hIonisation,     -1, 2, 2);
G4double demax = 0.05;  
G4double stmin = 1.e-9 * m;
G4hLowEnergyIonisation* lowEIonisation = new G4hLowEnergyIonisation();
pmanager->AddProcess( lowEIonisation, -1,3,3);
lowEIonisation->SetStepFunction( demax, stmin );
*Is there a threshold cut being applied that is inappropriate?


Definition of gas in DetectorConstruction:
//TPCgas_D2 is 100% D2
G4Element* D = new G4Element("Deuterium","D", z= 2., a= 2.0141*g/mole);  
G4Material* TPCgas_D2 = new G4Material("TPC_gas_D2",0.036*mg/cm3,1);  //0.2atm density
TPCgas_D2->AddElement(D,2);
*changing gas density has expected effect on particle path length;
*since the particle is created in the gas volume it never interacts
with any other material


Definition of deuteron in PrimaryEventGenerator:
G4ParticleDefinition* particle = particleTable->FindParticle("deuteron");
particleGun->SetParticleDefinition(particle);  
energy = 0.3*MeV;
p_z= G4UniformRand()*energy;
p_x = G4UniformRand()*(energy-p_z);
p_y = sqrt(energy*energy-p_x*p_x-p_z*p_z);
particleGun->SetParticleEnergy(energy);
particleGun->SetParticleMomentumDirection(G4ThreeVector(p_x,p_y,p_z));
particleGun->GeneratePrimaryVertex(anEvent);
*perhaps energy is per nucleon? (but doubling it doesn't solve the problem)
*perhaps this is total energy not kinetic energy?

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1 None: Re: low energy deuteron propagation   (Vladimir IVANTCHENKO - 30 Oct, 2007)
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