Radioactive source

Particles, Track, Event, Run and Biasing
1

Good mornig,
I am in the process of simulating a Ba133 radioactive source at a distance of 10 cm from a germanium detector, calculating the energy deposited in the crystal. I succeeded in doing this by using PrimaryGeneratorAction, in which I defined a point source emitting gammas. However, this is not accurate because, in reality, it is a radioactive source that undergoes decay.

I tried using testEm1 by adding PhysicsList, PhysicsListMessenger, and PhysListEmStandard, but it presents many problems . Presently, my program includes:

  • ActionInitialization
  • EventAction
  • HistoManager
  • DetectorConstruction where I have the scoring volume
  • RunAction
  • SteppingAction
  • PrimaryGeneratorActionpoint source emitting iso, gamma

I generate gammas and record each energy (using run.mac).

Please, how can I simulate a radioactive source at a distance of 10 cm from my detector?

thank you so much,
Adding,
Geant4 Version: 11.2.1
Operating System:Debian 6.1.119-1
Compiler/Version: gcc (Debian 12.2.0-14) 12.2.0
CMake Version: 3.25.1

2

What physics list are you using? If you want radioactive decay, then you need to enable such physics. Some good examples to run or borrow from are in the rdecay folder here.

A quirk to mention now it that once you have a decaying Ba133, you will need to make sure to explicitly set its energy to 0 since geant4 will decay it as a proper process. So with a 10 year half life, the global time to detection will be about as long since you will place the source with the generator, “wait” for the decay, than record it.