Hello experts!
I am interested in simulating the specular reflection of low-energy neutrons.
The process must implement
Sin(tetha_critical_angle) = U_eff / E
Sin(tetha) <= Sin(tetha_critical_angle).
In my task neutron interact with a material under 30 degrees with the energy 1.7*10^(-5) eV…
and U_eff = 60 neV.
I have found this code related this problem.
G4StepPoint* aStepPoint = 0;
if(aStep->GetPostStepPoint()->GetStepStatus() == fGeomBoundary && aStep->GetPostStepPoint()->GetPhysicalVolume()->GetName() == “MgfoilMat”)
{
aStepPoint = aStep->GetPostStepPoint();
G4ThreeVector pointInSurf = aStepPoint->GetPosition();
const G4VTouchable *aStepTouchable = aStepPoint->GetTouchable();
const G4AffineTransform *trans = aStepTouchable->GetHistory()->GetPtrTopTransform();
G4ThreeVector localPointInSurf = trans->TransformPoint(pointInSurf);
G4ThreeVector localNormal = aStepTouchable->GetVolume()->GetLogicalVolume()->GetSolid()->SurfaceNormal(localPointInSurf);
G4ThreeVector localDirection = trans->TransformAxis(aStepPoint->GetMomentumDirection());
G4double AngleToNormal = localDirection.angle(localNormal);
}
Thank you in advance.
_Geant4 Version:_11.03
_Operating System:_Ubuntu 23.10
Compiler/Version:
_CMake Version:_3.27.4