103 lines
3.3 KiB
C++
103 lines
3.3 KiB
C++
//$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
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// Muonium yields as a function of initial mu+ energies.
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// The method GetYields is used by MuFormation.
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// Id : yields.cc, v 1.1
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// Author: Taofiq PARAISO, T. Shiroka
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// Date : 2007-12
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// Notes : First implemented in Fortran by A. Hofer
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// C++ conversion by T.K. Paraiso 04-2005
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// Slight modifications by T. Shiroka
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//$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
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#include "yields.h"
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#include <iomanip>
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#include <fstream>
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#include <iostream>
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#include <stdlib.h>
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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The Muonium Yield function as well as the parameters are taken from:
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M. Gonin, R. Kallenbach, P. Bochsler: "Charge exchange of hydrogen atoms
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in carbon foils at 0.4 - 120 keV", Rev.Sci.Instrum. 65 (3), March 1994
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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Yields:: Yields(){;}
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Yields::~Yields(){;}
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void Yields::GetYields(
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double E, // kinetic energy in keV
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double mass, // mass in keV/c**2
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double yvector[3]) // pointer to the yields table
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{
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// Parameter NAMES for the muonium yield function
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double a_zero, a_minus;
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double k_Fermi, k_zero, k_minus;
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double two_k_Fermi;
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double k_Fermi_Quad, k_zero_Quad, k_minus_Quad;
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double vc_minus, vc_plus, v_Bohr, v_rel;
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// Parameter VALUES for the muonium yield function
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a_zero = 0.953;
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a_minus = 0.029;
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k_Fermi = 1.178; // [v_Bohr]
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k_Fermi_Quad = k_Fermi * k_Fermi;
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two_k_Fermi = 2. * k_Fermi;
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k_zero = 0.991*k_Fermi; // [v_Bohr]
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k_zero_Quad = k_zero * k_zero;
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k_minus = 0.989*k_Fermi; // [v_Bohr]
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k_minus_Quad = k_minus * k_minus;
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vc_minus = 0.284;
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vc_plus = 0.193; // [v_Bohr]
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v_Bohr = 7.2974E-3; // [c]
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// std::cout<<"E = "<< E <<std::endl;
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// Abort in case of negative energies ---------------------------
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if (E < 0)
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{
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std::cout<< "Error in method ''Yields'':" <<std::endl;
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std::cout<< "E = "<< E <<" < 0!" <<std::endl;
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std::cout<< "-> ABORTED!" <<std::endl;
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return;
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}
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//---------------------------------------------------------------
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// Definition of variables (aux_n are some auxiliary variables)
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// Calculate energy in (classical) terms of speed (in units of v_Bohr):
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v_rel = sqrt(2.*E/mass)/ v_Bohr;
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aux1 = v_rel*v_rel;
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aux2 = two_k_Fermi*v_rel;
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Q_zero = 1. + (k_zero_Quad - k_Fermi_Quad - aux1) / aux2;
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Q_minus = 1. + (k_minus_Quad - k_Fermi_Quad - aux1) / aux2;
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aux1 = a_zero * Q_zero;
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aux2 = a_minus * Q_minus;
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aux3 = (1.-Q_zero)*(1.-Q_minus);
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D = aux1*(aux2 + (1.-Q_minus)) + aux3;
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Yield_minus = aux1*aux2 / D;
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Yield_plus = aux3 / D;
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Yield_minus = Yield_minus* exp(-vc_minus/v_rel);
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Yield_plus = Yield_plus * exp(-vc_plus /v_rel);
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if(Yield_minus > exp(-vc_minus/v_rel)) Yield_minus=exp(-vc_minus/v_rel);
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if(Yield_plus > exp(-vc_plus/v_rel)) Yield_plus=exp(-vc_plus/v_rel);
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Yield_zero = 1. - (Yield_minus + Yield_plus);
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yvector[0]=Yield_plus;
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yvector[1]=Yield_zero;
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yvector[2]=Yield_minus;
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// std::cout<<"Y+ : "<< Yield_plus << std::endl;
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// std::cout<<"Y0 : "<< Yield_zero << std::endl;
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}
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