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//             LOW ENERGY MUON SPIN RELAXATION, ROTATION, RADIATION   Geant4 SIMULATION
//  ID    : YIELDS.cc , v 1.0
//  AUTHOR: Taofiq PARAISO
//  DATE  : 2005-04
//                   
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//                                 YIELDS
/*
  fIRST IMPLEMENTATION BY ANLSEM,H. IN FORTRAN
  C++ CONVERSION T.K.PARAISO 04-2005
*/
//$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$// 


#include "yields.h"
#include <iomanip>
#include <fstream>
#include <iostream>
#include <stdlib.h> 

/*  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
 Die Funktion sowie die Parameter sind uebernommen aus:

	M.Gonin, R.Kallenbach, P.Bochsler: 'Charge exchange of hydrogen atoms
	in carbon foils at 0.4 - 120 keV', Rev.Sci.Instrum. 65 (3), March 1994


fIRST IMPLEMENTATION BY ANLSEM,H. IN FORTRAN
C++ CONVERSION T.K.PARAISO 04-2005
c - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

Yields::Yields(){;}
Yields::~Yields(){;}

void Yields::GetYields(
       double E,	// kinetische Energie in keV
       double masse,// in keV / c**2
       double yvector[3])// pointer to yields table
{

  // YIELDS FUNCTIONS PRAMETERS
  double a_zero,a_minus;
  double k_Fermi,k_zero,k_minus;
  double zwo_k_Fermi;
  double k_Fermi_Quad,k_zero_Quad,k_minus_Quad;
  double vc_minus,vc_plus,v_Bohr,v_rel;


  // YIELDS FUNCTIONS PARAMETERs VALUES
  a_zero   = 0.953                   ;  
  a_minus = 0.029                    ;
  k_Fermi  = 1.178                   ;//	! [v_Bohr]
  k_Fermi_Quad = k_Fermi * k_Fermi   ;
  zwo_k_Fermi = 2. * k_Fermi         ;
  k_zero   = 0.991*k_Fermi           ;	//! [v_Bohr]
  k_zero_Quad = k_zero * k_zero      ;
  k_minus  = 0.989*k_Fermi           ;	// [v_Bohr]
  k_minus_Quad = k_minus * k_minus   ;
  vc_minus = 0.284                   ; 
  vc_plus = 0.193                    ;	// [v_Bohr]
  v_Bohr   = 7.2974E-3               ;	//  [c]
  
  
 
  //  std::cout<< "E = "<< E <<std::endl;
   
  // ABORT IF ENERGY NEGaTIVE-------------------------------------
  if (E < 0)
    {
      std::cout<< "Error in method ''Yields'':"<<std::endl;
      std::cout<< "E = "<< E <<" < 0!"<<std::endl;
      std::cout<< "-> ABORT!"<<std::endl;
      return;
    }
  //---------------------------------------------------------------
 


  // VARIABLES DEFINITION

  //Energie in Geschwindigkeit umrechnen (in Einheiten von v_Bohr):
  
  // - klassisch:
  
  v_rel = sqrt(2.*E/masse)/ v_Bohr;
  
  help1 = v_rel*v_rel;
  help2 = zwo_k_Fermi*v_rel;
  Q_zero  = 1. + (k_zero_Quad  - k_Fermi_Quad - help1) / help2;
  Q_minus = 1. + (k_minus_Quad - k_Fermi_Quad - help1) / help2;
  

  help1 = a_zero * Q_zero;
  help2 = a_minus * Q_minus;
  help3 = (1.-Q_zero)*(1.-Q_minus);
  D = help1*(help2 + (1.-Q_minus)) + help3;
  
  Yield_minus = help1*help2 / D;
  Yield_plus  = help3 / D;
  
  Yield_minus = Yield_minus* exp(-vc_minus/v_rel);
  Yield_plus  = Yield_plus * exp(-vc_plus /v_rel);
    
  if(Yield_minus > exp(-vc_minus/v_rel)) Yield_minus=exp(-vc_minus/v_rel);
  if(Yield_plus  > exp(-vc_plus/v_rel))  Yield_plus=exp(-vc_plus/v_rel);
  
  Yield_zero  = 1. - (Yield_minus + Yield_plus);

  yvector[0]=Yield_plus;
  yvector[1]=Yield_zero;
  yvector[2]=Yield_minus;

  //  std::cout<<"Y+ : "   << Yield_plus << std::endl;
  //  std::cout<<"Y0 : "   << Yield_zero << std::endl;

  

}