Which example does simulate time of flight?

First of all, GEANT4 provides examples in order to simulate energy deposition or dose deposited. I am interested to know which one example give a sample of how to measure time of fligth (TOF).

I measure the time of fligth in stepping action class. I understand that stepping action class is employed in all the steps through an entire event, so I just recorded the time for the first interaction with detector volume.

I made something like this:

G4int k1=0;

if (volume == fScoringVolume1 && k1==0) {
    G4StepPoint *preStepPoint = step->GetPreStepPoint();
    G4double tof1 = preStepPoint->GetGlobalTime();

I putted a counter k to avoid getting TOF in case the particle continues in the detector. I got an answer like this, but I do not know if it could be okay.

I will thank someone who can help me to validate my results or give me an GEANT4 example which makes something similar.