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// $Id: SteppingAction.cc,v 1.6 2007/03/15 15:52:39 maire Exp $
// GEANT4 tag $Name: geant4-09-03-cand-01 $
// 
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#include "SteppingAction.hh"
#include "DetectorConstruction.hh"
#include "PrimaryGeneratorAction.hh"
#include "RunAction.hh"
#include "HistoManager.hh"

#include "G4RunManager.hh"

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SteppingAction::SteppingAction(DetectorConstruction* det,
                               PrimaryGeneratorAction* prim, RunAction* RuAct, 
			       HistoManager* Hist)
:detector(det), primary(prim), runAction(RuAct), histoManager(Hist)
{ }

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SteppingAction::~SteppingAction()
{ }

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void SteppingAction::UserSteppingAction(const G4Step* aStep)
{
  G4StepPoint* prePoint = aStep->GetPreStepPoint();
  
  // if World --> return
  if (prePoint->GetTouchableHandle()->GetVolume()==detector->GetWorld()) return;
  
  // here we enter in the absorber Box
  // tag the event to be killed anyway after this step
  //
  G4RunManager::GetRunManager()->AbortEvent();
  
  //count processes and keep only Multiple Scattering
  //  
  G4StepPoint* endPoint = aStep->GetPostStepPoint();
  G4String procName = endPoint->GetProcessDefinedStep()->GetProcessName();
  runAction->CountProcesses(procName);
      
  if (procName != "msc" && procName != "stepMax") return;
  
  //below, only multiple Scattering happens
  //
  G4ThreeVector position  = endPoint->GetPosition();
  G4ThreeVector direction = endPoint->GetMomentumDirection();
  
  G4double truePathLength = aStep->GetStepLength();      
  G4double geomPathLength = position.x() + 0.5*detector->GetBoxSize();
  G4double ratio = geomPathLength/truePathLength;
  runAction->SumPathLength(truePathLength,geomPathLength);
  histoManager->FillHisto(1,truePathLength);
  histoManager->FillHisto(2,geomPathLength);
  histoManager->FillHisto(3,ratio);
   
  G4double yend = position.y(), zend = position.z();
  G4double lateralDisplacement = std::sqrt(yend*yend + zend*zend);
  runAction->SumLateralDisplacement(lateralDisplacement);
  histoManager->FillHisto(4,lateralDisplacement);
  
  G4double psi = std::atan(lateralDisplacement/geomPathLength); 
  runAction->SumPsi(psi);
  histoManager->FillHisto(5,psi);
  
  G4double xdir = direction.x(),  ydir = direction.y(), zdir = direction.z();
  G4double tetaPlane = std::atan2(ydir, xdir); 
  runAction->SumTetaPlane(tetaPlane);
  histoManager->FillHisto(6,tetaPlane);
  tetaPlane = std::atan2(zdir, xdir); 
  runAction->SumTetaPlane(tetaPlane);
  histoManager->FillHisto(6,tetaPlane);
  
  G4double phiPos = std::atan2(zend, yend); 
  histoManager->FillHisto(7,phiPos);
  G4double phiDir = std::atan2(zdir, ydir); 
  histoManager->FillHisto(8,phiDir);

  G4double phiCorrel = 0.;
  if (lateralDisplacement > 0.)  
    phiCorrel = (yend*ydir + zend*zdir)/lateralDisplacement;
  runAction->SumPhiCorrel(phiCorrel);
  histoManager->FillHisto(9,phiCorrel);    
}

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