48   void  GetFieldValue( 
const  double Point[4],
 
   49                double *Bfield          ) 
const;
 
   53   vector< vector< vector< double > > > fXField;
 
   55   vector< vector< vector< double > > > fYField;
 
   57   vector< vector< vector< double > > > fZField;
 
   61   G4double fMinix, fMaxix, fMiniy, fMaxiy, fMiniz, fMaxiz;
 
   65   G4float fGradient1, fGradient2, fGradient3, fGradient4;