00001 // 00002 // ******************************************************************** 00003 // * License and Disclaimer * 00004 // * * 00005 // * The Geant4 software is copyright of the Copyright Holders of * 00006 // * the Geant4 Collaboration. It is provided under the terms and * 00007 // * conditions of the Geant4 Software License, included in the file * 00008 // * LICENSE and available at http://cern.ch/geant4/license . These * 00009 // * include a list of copyright holders. * 00010 // * * 00011 // * Neither the authors of this software system, nor their employing * 00012 // * institutes,nor the agencies providing financial support for this * 00013 // * work make any representation or warranty, express or implied, * 00014 // * regarding this software system or assume any liability for its * 00015 // * use. Please see the license in the file LICENSE and URL above * 00016 // * for the full disclaimer and the limitation of liability. * 00017 // * * 00018 // * This code implementation is the result of the scientific and * 00019 // * technical work of the GEANT4 collaboration. * 00020 // * By using, copying, modifying or distributing the software (or * 00021 // * any work based on the software) you agree to acknowledge its * 00022 // * use in resulting scientific publications, and indicate your * 00023 // * acceptance of all terms of the Geant4 Software license. * 00024 // ******************************************************************** 00025 // 00026 // 00027 // 00028 // $Id: G4MagHelicalStepper.hh 69786 2013-05-15 09:38:51Z gcosmo $ 00029 // 00030 // 00031 // 00032 // class G4MagHelicalStepper 00033 // 00034 // Class description: 00035 // 00036 // Abstract base class for integrator of particle's equation of motion, 00037 // used in tracking in space dependent magnetic field 00038 00039 // History: 00040 // - 05.11.98 J.Apostolakis Creation of new ABC 00041 // -------------------------------------------------------------------- 00042 00043 #ifndef G4MagHelicalStepper_hh 00044 #define G4MagHelicalStepper_hh 00045 00046 #include <CLHEP/Units/PhysicalConstants.h> 00047 00048 #include "G4Types.hh" 00049 #include "G4MagIntegratorStepper.hh" 00050 #include "G4Mag_EqRhs.hh" 00051 #include "G4ThreeVector.hh" 00052 00053 class G4MagHelicalStepper : public G4MagIntegratorStepper 00054 { 00055 public: // with description 00056 00057 G4MagHelicalStepper(G4Mag_EqRhs *EqRhs); 00058 virtual ~G4MagHelicalStepper(); 00059 00060 virtual void Stepper( const G4double y[], // VIRTUAL for ExactHelix - temporary 00061 const G4double dydx[], 00062 G4double h, 00063 G4double yout[], 00064 G4double yerr[] ); 00065 // The stepper for the Runge Kutta integration. 00066 // The stepsize is fixed, equal to h. 00067 // Integrates ODE starting values y[0 to 6] 00068 // Outputs yout[] and its estimated error yerr[]. 00069 00070 virtual void DumbStepper( const G4double y[], 00071 G4ThreeVector Bfld, 00072 G4double h, 00073 G4double yout[] ) = 0; 00074 // Performs a 'dump' Step without error calculation. 00075 00076 G4double DistChord()const ; 00077 // Estimate maximum distance of curved solution and chord ... 00078 00079 protected: // with description 00080 00081 inline void LinearStep( const G4double yIn[], 00082 G4double h, 00083 G4double yHelix[]) const; 00084 // A linear Step in regions without magnetic field. 00085 00086 void AdvanceHelix( const G4double yIn[], 00087 G4ThreeVector Bfld, 00088 G4double h, 00089 G4double yHelix[],G4double yHelix2[]=0); // output 00090 // A first order Step along a helix inside the field. 00091 00092 inline void MagFieldEvaluate( const G4double y[], G4ThreeVector& Bfield ); 00093 // Evaluate the field at a certain point. 00094 00095 00096 inline G4double GetInverseCurve( const G4double Momentum, const G4double Bmag ); 00097 // Evaluate Inverse of Curvature of Track 00098 00099 // Store and use the parameters of track : 00100 // Radius of curve, Stepping angle, Radius of projected helix 00101 inline void SetAngCurve(const G4double Ang); 00102 inline G4double GetAngCurve()const; 00103 00104 inline void SetCurve(const G4double Curve); 00105 inline G4double GetCurve()const; 00106 00107 inline void SetRadHelix(const G4double Rad); 00108 inline G4double GetRadHelix()const; 00109 00110 00111 protected: // without description 00112 00113 // void MagFieldEvaluate( const G4double y[], G4double B[] ) 00114 // { GetEquationOfMotion()-> GetFieldValue(y, B); } 00115 00116 private: 00117 00118 G4MagHelicalStepper(const G4MagHelicalStepper&); 00119 G4MagHelicalStepper& operator=(const G4MagHelicalStepper&); 00120 // Private copy constructor and assignment operator. 00121 00122 static const G4double fUnitConstant; // As in G4Mag_EqRhs.hh/cc where it is not used. 00123 private: 00124 00125 G4Mag_EqRhs* fPtrMagEqOfMot; 00126 00127 // Data stored in order to find the chord. 00128 G4double fAngCurve; 00129 G4double frCurve; 00130 G4double frHelix; 00131 // Data stored in order to find the chord. 00132 G4ThreeVector yInitial, yMidPoint, yFinal; 00133 00134 00135 }; 00136 00137 #include "G4MagHelicalStepper.icc" 00138 00139 #endif /* G4MagHelicalStepper_hh */