Gabriele Cosmo
209 lines
7.3 KiB
C++
209 lines
7.3 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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#ifndef G4ProjectileFragmentCrossSection_h
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#define G4ProjectileFragmentCrossSection_h 1
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#include <cmath>
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#include <iostream>
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#include "G4Exp.hh"
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#include "G4Log.hh"
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#include "G4Pow.hh"
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// Implements Physical Review C61, 034607 (2000)
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// Rewrite starting from EPAX Version 2
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class G4ProjectileFragmentCrossSection
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{
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public:
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G4ProjectileFragmentCrossSection()
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{
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p_S[1] = -2.38; // scale factor for xsect in barn
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p_S[2] = 0.27;
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p_P[1] = -2.5840E+00; // slope of mass yield curve
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p_P[2] = -7.5700E-03;
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p_Delta[1] = -1.0870E+00; // centroid rel. to beta-stability
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p_Delta[2] = +3.0470E-02;
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p_Delta[3] = +2.1353E-04;
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p_Delta[4] = +7.1350E+01;
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p_R[1] = +0.885E+00; // width parameter R
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p_R[2] = -9.8160E-03;
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p_Un[1] = 1.65; // slope par. n-rich ride of Z distr.
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p_Up[1] = 1.7880; // slope par. p-rich ride of Z distr.
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p_Up[2] = +4.7210E-03;
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p_Up[3] = -1.3030E-05;
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p_mn[1] = 0.400; // memory effect n-rich projectiles
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p_mn[2] = 0.600;
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p_mp[1] = -10.25; // memory effect p-rich projectiles
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p_mp[2] = +10.1;
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corr_d[1] = -25.0; // correction close to proj.: centroid dzp
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corr_d[2] = 0.800;
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corr_r[1] = +20.0; // correction close to proj.: width R
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corr_r[2] = 0.820;
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corr_y[1] = 200.0; // correction close to proj.: Yield_a
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corr_y[2] = 0.90;
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}
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inline G4double doit(G4double Ap, G4double Zp, G4double At, G4double Zt, G4double A, G4double Z)
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{
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// calculate mass yield
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G4double Ap13 = G4Pow::GetInstance()->powA(Ap, 1./3.);
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G4double At13 = G4Pow::GetInstance()->powA(At, 1./3.);
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G4double S = p_S[2] * (At13 + Ap13 + p_S[1]);
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// std::cout << "debug0 "<<S<<" "<<At13<<" "<<Ap13<<" "<<p_S[1]<<" "<<p_S[2]<<std::endl;
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G4double p = G4Exp(p_P[2]*Ap + p_P[1]);
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G4double yield_a = p * S * G4Exp(-p * (Ap - A));
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// std::cout << "debug1 "<<yield_a<<std::endl;
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// modification close to projectile
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G4double f_mod_y=1.0;
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if (A/Ap > corr_y[2])
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{
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f_mod_y=corr_y[1]*G4Pow::GetInstance()->powN(A/Ap-corr_y[2], 2) + 1.0;
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}
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yield_a= yield_a * f_mod_y;
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// std::cout << "debug1 "<<yield_a<<std::endl;
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// calculate maximum of charge dispersion zprob
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G4double zbeta = A/(1.98+0.0155*G4Pow::GetInstance()->powA(A, (2./3.)));
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G4double zbeta_p = Ap/(1.98+0.0155*G4Pow::GetInstance()->powA(Ap, (2./3.)));
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G4double delta;
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if(A > p_Delta[4])
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{
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delta = p_Delta[1] + p_Delta[2]*A;
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}
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else
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{
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delta = p_Delta[3]*A*A;
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}
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// modification close to projectile
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G4double f_mod=1.0;
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if(A/Ap > corr_d[2])
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{
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f_mod = corr_d[1]*G4Pow::GetInstance()->powN(A/Ap-corr_d[2], 2) + 1.0;
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}
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delta = delta*f_mod;
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G4double zprob = zbeta+delta;
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// correction for proton- and neutron-rich projectiles
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G4double dq;
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if((Zp-zbeta_p)>0)
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{
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dq = G4Exp(p_mp[1] + G4double(A)/G4double(Ap)*p_mp[2]);
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// std::cout << "dq "<<A<<" "<<Ap<<" "<<p_mp[1]
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// <<" "<<p_mp[2]<<" "<<dq<<" "<<p_mp[1] + A/Ap*p_mp[2]<<std::endl;
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}
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else
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{
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dq = p_mn[1]*G4Pow::GetInstance()->powN(A/Ap, 2) + p_mn[2]*G4Pow::GetInstance()->powN(A/Ap, 4);
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}
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zprob = zprob + dq * (Zp-zbeta_p);
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// small corr. since Xe-129 and Pb-208 are not on Z_beta line
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zprob = zprob + 0.0020*A;
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// std::cout <<"zprob "<<A<<" "<<dq<<" "<<Zp<<" "<<zbeta_p
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// <<" "<<zbeta<<" "<<delta<<std::endl;
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// calculate width parameter R
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G4double r = G4Exp(p_R[1] + p_R[2]*A);
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// modification close to projectile
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f_mod=1.0;
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if (A/Ap > corr_r[2])
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{
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f_mod = corr_r[1]*Ap*G4Pow::GetInstance()->powN(A/Ap-corr_r[2], 4)+1.0;
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}
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r = r*f_mod;
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// change width according to dev. from beta-stability
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if ((Zp-zbeta_p) < 0.0)
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{
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r=r*(1.0-0.0833*std::abs(Zp-zbeta_p));
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}
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// calculate slope parameters u_n, u_p
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G4double u_n = p_Un[1];
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G4double u_p = p_Up[1] + p_Up[2]*A + p_Up[3]*A*A;
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// calculate charge dispersion
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G4double expo, fract;
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if((zprob-Z) > 0)
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{
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// neutron-rich
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expo = -r*G4Pow::GetInstance()->powA(std::abs(zprob-Z), u_n);
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fract = G4Exp(expo)*std::sqrt(r/3.14159);
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}
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else
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{
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// proton-rich
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expo = -r*G4Pow::GetInstance()->powA(std::abs(zprob-Z), u_p);
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fract = G4Exp(expo)*std::sqrt(r/3.14159);
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// std::cout << "1 "<<expo<<" "<<r<<" "<<zprob<<" "<<Z<<" "<<u_p<<std::endl;
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// go to exponential slope
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G4double dfdz = 1.2 + 0.647*G4Pow::GetInstance()->powA(A/2.,0.3);
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G4double z_exp = zprob + dfdz * G4Log(10.) / (2.*r);
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if( Z>z_exp )
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{
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expo = -r*G4Pow::GetInstance()->powA(std::abs(zprob-z_exp), u_p);
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fract = G4Exp(expo)*std::sqrt(r/3.14159)
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/ G4Pow::GetInstance()->powA(G4Pow::GetInstance()->powA(10, dfdz), Z-z_exp);
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}
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}
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// std::cout << "debug "<<fract<<" "<<yield_a<<std::endl;
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G4double epaxv2=fract*yield_a;
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return epaxv2;
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}
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void testMe()
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{
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G4ProjectileFragmentCrossSection i;
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// std::cout << i.doit(58, 28, 9, 4, 49, 28) << std::endl;
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// Sigma = 9.800163E-13 b
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}
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private:
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G4double p_S[3];
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G4double p_P[3];
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G4double p_Delta[5];
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G4double p_R[3];
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G4double p_Un[2];
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G4double p_Up[4];
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G4double p_mn[3];
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G4double p_mp[3];
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G4double corr_d[3];
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G4double corr_r[3];
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G4double corr_y[3];
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};
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#endif
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