initial working version: 80 scintillators in 8 layers, root output, mono-energetic muon on -Z direction

include/PrimaryGeneratorAction.hh

@@ -0,0 +1,37 @@
+
+#ifndef PrimaryGeneratorAction_h
+#define PrimaryGeneratorAction_h 1
+
+#include "G4VUserPrimaryGeneratorAction.hh"
+#include "G4ParticleGun.hh"
+#include "globals.hh"
+
+class G4ParticleGun;
+class G4Event;
+class G4Box;
+
+/// The primary generator action class with particle gun.
+///
+/// The default kinematic is a 6 MeV gamma, randomly distribued 
+/// in front of the phantom across 80% of the (X,Y) phantom size.
+
+class PrimaryGeneratorAction : public G4VUserPrimaryGeneratorAction
+{
+  public:
+    PrimaryGeneratorAction();    
+    virtual ~PrimaryGeneratorAction();
+
+    // method from the base class
+    virtual void GeneratePrimaries(G4Event*);         
+  
+    // method to access particle gun
+    const G4ParticleGun* GetParticleGun() const { return fParticleGun; }
+  
+  private:
+    G4ParticleGun*  fParticleGun; // pointer a to G4 gun class
+    G4Box* fEnvelopeBox;
+};
+
+//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
+
+#endif