Meaning of ,histories'?

[bsarey]

Dear Community,

as someone that also uses the Geant4 framework I'm a little bit confused about the term of particle histories in DOSXYZnrc.

So in Geant4 one history describes (for the case of a linac/x-ray tube) one electron and all the secondaries resulting from the interaction with the target material.

When I want to calculate the dose in a phantom in DOSXYZnrc with a phase space file scored in the Geant4 framework, do I have to give the NCASE variable the same number as the #histories registered in the phase space file to use all the secondary photons in it?

Thanks

[rtownson]

In the case of phase-space sources, ncase is the number of particles to use from the source (not the number of histories). We also define a history as a primary and all of its secondaries, but I believe the term is occasionally misused in the documentation. If you would like any further clarification you are welcome to ask!