I collected the coordinates of each step and then visualized them,and finally want to draw such a picture as:
But the result is:
I considered setting the max step length
G4double maxStep = 0.05*um;
auto fStepLimit = new G4UserLimits(maxStep);
logic_ZnS->SetUserLimits(fStepLimit);
which result in
The trajectory of each particle in the figure always seems to have a fixed distance on the x-axis.