Confirmation of how to use GetTouchable and his applicatives

Particles, Track, Event, Run and Biasing
1

Hello all,

I hope you’re fine.

I’m having some questions about the GetTouchable() function.

  1. Get the G4PhantomParameterisation

I saw in some code that we can get the G4PhantomParameterisation associated with the current G4Track* doing something like:

  auto vol = track->GetTouchable()->GetVolume();
  if(!vol) return;

  auto phantomParam = dynamic_cast<G4PhantomParameterisation*>(vol->GetParameterisation());

Is that true? I would have thought that it is not the G4VPhysicalVolume in the phantom sense that would be returned, but a voxel ; but again, maybe a “voxel” isn’t a G4VPhysicalVolume?

  1. GetCopyNumber()

Also, when a G4Track track is inside a G4PhantomParameterisation, I can use…

G4int copyNo = track.GetTouchable()->GetCopyNumber();

… to get the copy number of the current voxel where the G4Track is located?

  1. Convert global direction to local direction

I have also written a function that convert global direction to local direction in the case of a G4Track& track inside of a G4PhantomParameterisation:

G4ThreeVector ConvertToLocalDirection(const G4Track& track, const G4ThreeVector& globalDir) const
{
  G4TouchableHistory* hist = dynamic_cast<G4TouchableHistory*>(track.GetTouchable());
  G4ThreeVector localDir = hist->GetTransform(hist->GetDepth()).TransformAxis(globalDir);
  
  return localDir;
}

Is it correct? Are there other ways to do this in a more optimized way?

Is always the GetTouchable of a G4Track a G4TouchableHistory?

For information :
Geant4 Version: 11.2.2
Operating System: Windows and Linux

Thanks a lot,