What is the difference between hit and step?

Hello! Thank you for your browsing.

It there any diffencence between hit and step?
They are the same things?
One hit means one step ?

A “step”, G4Step, is one segment of the particle’s trajectory: it has a start (the “PreStepPoint” G4StepPoint) and an end (the “PostStepPoint” G4StepPoint), and is treated as a straight line between those points. The step carries with it information about any secondaries that got created during the step, energy lost by the particle which didn’t go to secondaries, whether the particle is entering or leaving a volume, and so on.

A “hit” (subclass of G4VHit) is recorded by a “sensitive detector” (SD) at the end of a step. It consists minimally of the post-step position and the energy deposited. Since the user can write their own SD code and their own hit container, you can record anything else you want as part of the hit.


Thanks for your reply!
I think I have understood.
Many thanks!