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Question Trouble with Cs137 decay 

Keywords: radioactive decay
Forum: Event and Track Management
Date: 21 Nov, 2005
From: Andrew <Andrew>

I am trying to decay Cs137. The simulation does the beta decay of Cs137 and generates the excited Ba137 ion. My problem is that I can't figure out how to decay the Ba137 to get the 662 keV gamma. My approach was to follow the advice of thread 147 in the Physics List forum and set the lifetime of the Ba137[661.7] particle to 0 in G4UserStackingAction::ClassifyNewTrack(). However, I found that no particle with name "Ba137[661.7]" ever shows up in my ClassifyNewTrack function. The original Cs137[0.0], electron, and anti-neutrino appear in the ClassifyNewTrack() function, but not the Ba137[661.7]. It appears that the Ba137[661.7] is not decayed, is not tracked through the geometry, and doesn't even get put onto the stack. If anyone has solved this problem before please offer some advice. In case it is useful, I attach below the relevant output from the code:

G4NuclearDecayChannel::BetaDecayIt   create decay products in rest frame 
 ----- List of DecayProducts  -----
 ------ Parent Particle ----------
 Particle type - Cs137[0.0]
   mass:        127.5[GeV]
   charge:      55[e]
   Direction x: 0, y: 0, z: 0
   Total Momentum = 0[GeV]
   Momentum: 0[GeV], y: 0[GeV], z: 0[GeV]
   Total Energy   = 127.5[GeV]
   Kinetic Energy = 0[GeV]
   ProperTime     = 0[ns]
 ------ Daughter Particles  ------
 ----------1 -------------
 Particle type - e-
   mass:        0.000510999[GeV]
   charge:      -1[e]
   Direction x: -0.145038, y: -0.349169, z: -0.925767
   Total Momentum = 0.00025763[GeV]
   Momentum: -3.73662e-05[GeV], y: -8.99562e-05[GeV], z: -0.000238505[GeV]
   Total Energy   = 0.00057227[GeV]
   Kinetic Energy = 6.1271e-05[GeV]
   ProperTime     = 0[ns]
 ----------2 -------------
 Particle type - anti_nu_e
   mass:        0[GeV]
   charge:      0[e]
   Direction x: 0.149655, y: -0.202306, z: 0.96782
   Total Momentum = 0.0004527[GeV]
   Momentum: 6.77488e-05[GeV], y: -9.15838e-05[GeV], z: 0.000438132[GeV]
   Total Energy   = 0.0004527[GeV]
   Kinetic Energy = 0.0004527[GeV]
   ProperTime     = 0[ns]
 ----------3 -------------
 Particle type - Ba137[661.7]
   mass:        127.499[GeV]
   charge:      56[e]
   Direction x: -0.111893, y: 0.668572, z: -0.735181
   Total Momentum = 0.000271534[GeV]
   Momentum: -3.03826e-05[GeV], y: 0.00018154[GeV], z: -0.000199627[GeV]
   Total Energy   = 127.499[GeV]
   Kinetic Energy = 2.89142e-10[GeV]
   ProperTime     = 0[ns]
 ----- End List of DecayProducts  -----

G4ContinuumGammaDeexcitation::CreateTransition - Created
G4ContinuumGammaDeexcitation::CanDoTransition -  Excitation 0.661659 below max discrete level 4.7653
G4VGammaDeexcitation::DoChain - Transition deleted, end of chain 
 = BreakItUp = 0 gammas from ContinuumDeexcitation 
G4DiscreteGammaDeexcitation::CreateTransition - (A,Z) is valid 
G4DiscreteGammaDeexcitation::CreateTransition - Created from level energy 0.661659, excitation is 0.661659
G4DiscreteGammaDeexcitation::CanDoTransition -  Excitation 0.661659, Min-Max are 0.28341 4.7653
G4DiscreteGammaDeexcitation::CanDoTransition -  Halflife 1.53e+11, Calling from RDM  False  Max-HL = 1000
G4DiscreteGammaDeexcitation::CanDoTransition - CanDo: False 
G4VGammaDeexcitation::DoChain - Transition deleted, end of chain 
 = BreakItUp = 0 gammas from DiscreteDeexcitation 
 = BreakItUp = Nucleus added to products
*-*-* Photon evaporation: 1

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