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Question Annihilation decay of Positronium in matter. 

Forum: Physics List
Date: 02 Aug, 2016
From: Andreas Gad <Andreas Gad>

Hello, I am doing a simulation on excitation of positroium as a step in creating antihydrogen. I have defined the properties of the particle and added one decay channel which is the spontaneous decay into three photons. Now I need to add the possibility of annihilation with the walls of the detector construction. Does anyone know how to approach this? Thank you in advance.

The code where Ps is defined is attached below.

	const G4String name = "ps";

	// search in particle table]
	G4ParticleTable* pTable = G4ParticleTable::GetParticleTable();
	G4ParticleDefinition* anInstance = pTable->FindParticle(name);
	if (anInstance == 0) {
		// create particle
		//
		//    Arguments for constructor are as follows
		//               name             mass          width         charge
		//             2*spin           parity  C-conjugation
		//          2*Isospin       2*Isospin3       G-parity
		//               type    lepton number  baryon number   PDG encoding
		//             stable         lifetime    decay table
		//             shortlived      subType    anti_encoding

		// use constants in CLHEP
		//  static const double electron_mass_c2 = 0.51099906 * MeV;

		anInstance = new G4ParticleDefinition(
				     name,  2.0*electron_mass_c2,       0.0*MeV,    0.0, 
				2,                 0,             0,          
				0,                 0,             0,             
			 "lepton",                 2,             0,          0,
			 false,              142.3,          NULL,
				 false,                  "e"
				  );

		// Bohr Magnetron
		G4double muB =  -0.5*eplus*hbar_Planck/(electron_mass_c2/c_squared) ;

		anInstance->SetPDGMagneticMoment( 2.0 * muB * 1.00115965218076 );

		// Create Decay Table
		G4DecayTable* DecayTable = new G4DecayTable();

		// Create a decay channel
		G4VDecayChannel *ThreeGamma = new PsThreeGammaDecayChannel();
		// Insert the decay channel in the decay table
		DecayTable->Insert(ThreeGamma);

		anInstance->SetDecayTable(DecayTable);

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1 Note: Re: Annihilation decay of Positronium in matter.   (Andreas Gad - 05 Aug, 2016)
(_ Idea: Re: Annihilation decay of Positronium in matter.   (Vladimir Ivanchenko - 24 Oct, 2016)
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