Hello, I’ve this geometry

and I can simulate a particle source using the GPS, for example

########## Particles ##########
/gps/particle gamma
/gps/energy 1808.65 keV
/gps/pos/type Volume
/gps/pos/shape Sphere
/gps/pos/centre .0 .0 3.67 cm
/gps/pos/halfz 16.4 cm
/gps/ang/type iso
/gps/source/intensity 1
/gps/pos/confine sample

########## Number of particles ##########
/run/printProgress 10
/run/beamOn 100

Now instead of using the single photons (as I do in in the sketch of the macro), my source has to be radionuclide dacay. In particular I’ve to simulate the decays of Am-241, Co-60, Cs-137, Cs-134, Pb-210.

What should I do to use the radionuclide decays as source?

Hi @faca87 ,
Change first two lines of your mac to
/gps/particle ion
/gps/ion 27 60 0 0
/gps/energy 0. 0. eV

Rest remain same.

Thank you @drvijayraj

Regarding the physics list, in my main file I’ve

``````// Physics list
G4VModularPhysicsList* physicsList = new QBBC;
physicsList->SetVerboseLevel(1);
//  runManager->SetUserInitialization(physicsList);
runManager->SetUserInitialization(new gem90PhysicsList);
``````

where gem90PhysicsList calls the external file
gem90PhysicsList.cc (9.4 KB)
How to include also the radioactive physics?

You should try running the macro.

I get some deposited energy, and I see photons production …do you think I can be sure it is from radioactive decay?

Yeah !! You are good to go with more events.

Well,thank you @drvijayraj !