Moved Tao's code to TaoLEMuSR.

geant4/TaoLEMuSR/include/LEMuSRAtRestSpinRotation.hh

@@ -0,0 +1,161 @@
+//$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
+//             LOW ENERGY MUON SPIN RELAXATION, ROTATION, RADIATION 
+//
+//  ID    : LEMuSRAtRestSpinRotation.hh , v 1.3
+//  AUTHOR: Taofiq PARAISO
+//  DATE  : 2006-01-19 16:15
+//$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
+//
+//  &           &&&&&&&&&&                            &&&&&&&         &&&&&&&&
+//  &           &                                   &&      &&       &       &&
+//  &           &                   &      &       &                &       &&
+//  &           &&&&&&&            &      &         &&&&&&         &&&&&&&&  
+//  &           &                 &      &&                &      &      &&
+//  &           &                &&     &  &     &&      &&      &        &
+//  &&&&&&&&&&  &&&&&&&&&&      &  &&&&&    &&    &&&&&&&       &        &&   
+//                             &
+//                            &
+//                           &
+//                         &  
+//                               AT REST SPIN ROTATION   
+//$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
+
+
+
+/**
+ *The LEMuSRAtRestSpinRotation class contains the implementation of the muon spin 
+ *precession in a magnetic field when the muon is at rest.
+ *
+ *To implement a process one should create a particle change object.
+ *
+ *Indeed, in Geant4, a process is simply the change of an old particle to a new
+ *one. Hence, this spin rotation process will just replace the muon by another
+ *one with spin rotated, but same parameters of time, position, etc.
+ *
+ *The particle change object registers all the parameters of the new particle, 
+ *like the change in time, the momentum direction, the position, the polarization but also
+ *the type of the particle, which can be changed also as in the muonium formation
+ *process (cf.LEMuSRMUONIUM ).
+ *
+ *At each step of a track Geant4 we check the list possible processes to excecute
+ *(cf. LEMuSRPhysicsList) and will select them according to the priority which was
+ *given by the user and to the state of the particle. Indeed, the user should
+ *indicate if the process should be ran at rest, before and/or after the step.
+ *
+ *
+ *Some processes can be implemented such that the behaviour in different in those
+ *three different cases.
+ *
+ *Hence the class G4VProcess contains three important virtual methods:
+ * -# PreStepDoIt()
+ * -# PostStepDoIt()
+ * -# AtRestDoIt()
+ * . 
+ *In the present implementation, we only use the  AtRestDoIt() method.
+*/
+
+
+#ifndef LEMUSRATRESTSPINROTATION_H
+#define LEMUSRATRESTSPINROTATION_H 1
+
+
+#include "G4VRestProcess.hh"
+#include "G4DynamicParticle.hh"
+#include "G4MagneticField.hh"
+#include "G4ParticleTypes.hh"
+#include "globals.hh"
+#include "G4VParticleChange.hh"
+#include "G4ios.hh"
+#include "G4ForceCondition.hh"
+#include "G4ParticleChangeForTransport.hh"
+#include "LEMuSRParticleChangeForSR.hh"
+#include "G4EventManager.hh"
+
+/*!
+ * This class is a public class of the G4VRestProcess class, 
+ * which contains virtual methods to execute a process when a particle
+ * is at rest.
+ */
+class LEMuSRAtRestSpinRotation : public G4VRestProcess
+{
+
+
+public:
+  
+//! The constructor specifies the process name.
+  LEMuSRAtRestSpinRotation(const G4String& processName =  "SpinRotationAtRest" );
+  LEMuSRAtRestSpinRotation(G4VRestProcess& );
+  
+  virtual ~LEMuSRAtRestSpinRotation();
+ 
+  //! Method to return a pointer to the spin rotation process instance. 
+  static LEMuSRAtRestSpinRotation* GetInstance();
+
+  
+private: 
+  
+//! The pointer to the process
+  /**
+      One can use it to communicate with the process and get information about different parameters
+    */ 
+  static LEMuSRAtRestSpinRotation* pointer;
+  
+  
+public:
+
+
+  //!The main method to execute the spin precession process.
+  G4VParticleChange* AtRestDoIt(const G4Track& theTrack, const G4Step& theStep);
+  
+  
+  G4double
+  //! The muon position-time is given to the method GetFieldValue in order to get the magnetic field vector.
+  point[4];
+  G4double 
+  //! The magnetic field vector at the point[4] position.
+  B[3], 
+    //! The rotation frequency
+    fqz,
+    //! The spin rotation angle computed in the RotateSpin method
+    rotation_angle;
+
+  G4double 
+  //! The initial time. 
+  itime, 
+    //! The final time.
+    ftime, 
+    //! The time variation. 
+    deltatime;
+
+  
+  G4ThreeVector SpinDirection;
+
+  //! The particle change object which stores all the proposed modification of the particle's state.
+  LEMuSRParticleChangeForSR theParticleChange;
+  
+
+  const G4Field *mfield;
+
+
+
+  void  RotateSpin(const G4Step&, G4ThreeVector, G4double);
+  //! Returns the precession frequency according to the particle:
+  /*!
+   *- For muons and all other particles \f$ \gamma= 8.5062e+7*rad/(s*kGauss)\f$
+   *- For muonium \f$ \gamma=*rad/(s*kGauss) \f$
+   */
+  G4double GetGyromagneticRatio();
+  
+  inline G4double GetMeanLifeTime(const G4Track&, G4ForceCondition* condition)
+  {
+    *condition = Forced;
+    return DBL_MAX;
+  }
+  
+  /*! The particle's polarization vector.*/ 
+  G4ThreeVector polar;  
+  
+  
+  
+};
+#endif