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Please see the license in the file LICENSE and URL above * // * for the full disclaimer and the limitation of liability. * // * * // * This code implementation is the result of the scientific and * // * technical work of the GEANT4 collaboration. * // * By using, copying, modifying or distributing the software (or * // * any work based on the software) you agree to acknowledge its * // * use in resulting scientific publications, and indicate your * // * acceptance of all terms of the Geant4 Software license. * // ******************************************************************** // // $Id: G4PreCompoundAlpha.cc,v 1.7 2010/08/28 15:16:55 vnivanch Exp $ // GEANT4 tag $Name: geant4-09-03-ref-09 $ // // ------------------------------------------------------------------- // // GEANT4 Class file // // // File name: G4PreCompoundAlpha // // Author: V.Lara // // Modified: // 21.08.2008 J. M. Quesada add choice of options // 20.08.2010 V.Ivanchenko added G4Pow and G4PreCompoundParameters pointers // use int Z and A and cleanup // #include "G4PreCompoundAlpha.hh" #include "G4Alpha.hh" G4PreCompoundAlpha::G4PreCompoundAlpha() : G4PreCompoundIon(G4Alpha::Alpha(), &theAlphaCoulombBarrier) {} G4PreCompoundAlpha::~G4PreCompoundAlpha() {} G4double G4PreCompoundAlpha::FactorialFactor(G4int N, G4int P) { return G4double((N-4)*(P-3)*(N-3)*(P-2)*(N-2)*(P-1)*(N-1)*P)/12.0; } G4double G4PreCompoundAlpha::CoalescenceFactor(G4int A) { return 4096.0/G4double(A*A*A); } G4double G4PreCompoundAlpha::GetRj(G4int nParticles, G4int nCharged) { G4double rj = 0.0; if(nCharged >=2 && (nParticles-nCharged) >=2 ) { G4double denominator = G4double(nParticles*(nParticles-1)*(nParticles-2)*(nParticles-3)); rj = 6.0*nCharged*(nCharged-1)*(nParticles-nCharged)*(nParticles-nCharged-1) /denominator; } return rj; } ///////////////////////////////////////////////////////////////////////////////// //J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections //OPT=0 Dostrovski's parameterization //OPT=1,2 Chatterjee's paramaterization //OPT=3,4 Kalbach's parameterization // G4double G4PreCompoundAlpha::CrossSection(G4double K) { ResidualA = GetRestA(); ResidualZ = GetRestZ(); theA = GetA(); theZ = GetZ(); ResidualAthrd = ResidualA13(); FragmentA = theA + ResidualA; FragmentAthrd = g4pow->Z13(FragmentA); if (OPTxs==0) { return GetOpt0( K); } else if( OPTxs==1 || OPTxs==2) { return GetOpt12( K); } else if (OPTxs==3 || OPTxs==4) { return GetOpt34( K); } else{ std::ostringstream errOs; errOs << "BAD Alpha CROSS SECTION OPTION !!" < 50*MeV) { Kc = 50*MeV; } G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs; G4double p0 = 10.95; G4double p1 = -85.2; G4double p2 = 1146.; G4double landa0 = 0.0643; G4double landa1 = -13.96; G4double mu0 = 781.2; G4double mu1 = 0.29; G4double nu0 = -304.7; G4double nu1 = -470.0; G4double nu2 = -8.580; G4double delta=1.2; Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta); p = p0 + p1/Ec + p2/(Ec*Ec); landa = landa0*ResidualA + landa1; G4double resmu1 = g4pow->powZ(ResidualA,mu1); mu = mu0*resmu1; nu = resmu1*(nu0 + nu1*Ec + nu2*(Ec*Ec)); q = landa - nu/(Ec*Ec) - 2*p*Ec; r = mu + 2*nu/Ec + p*(Ec*Ec); ji=std::max(Kc,Ec); if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;} else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;} if (xs <0.0) {xs=0.0;} return xs; } // *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)************* G4double G4PreCompoundAlpha::GetOpt34(G4double K) // c ** alpha from huizenga and igo { G4double landa, mu, nu, p , signor(1.),sig; G4double ec,ecsq,xnulam,etest(0.),a; G4double b,ecut,cut,ecut2,geom,elab; G4double flow = 1.e-18; G4double spill= 1.e+18; G4double p0 = 10.95; G4double p1 = -85.2; G4double p2 = 1146.; G4double landa0 = 0.0643; G4double landa1 = -13.96; G4double mu0 = 781.2; G4double mu1 = 0.29; G4double nu0 = -304.7; G4double nu1 = -470.0; G4double nu2 = -8.580; G4double ra=1.20; //JMQ 13/02/09 increase of reduced radius to lower the barrier // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra); ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra); ecsq = ec * ec; p = p0 + p1/ec + p2/ecsq; landa = landa0*ResidualA + landa1; a = g4pow->powZ(ResidualA,mu1); mu = mu0 * a; nu = a* (nu0+nu1*ec+nu2*ecsq); xnulam = nu / landa; if (xnulam > spill) { xnulam=0.; } if (xnulam >= flow) { etest = 1.2 *std::sqrt(xnulam); } a = -2.*p*ec + landa - nu/ecsq; b = p*ecsq + mu + 2.*nu/ec; ecut = 0.; cut = a*a - 4.*p*b; if (cut > 0.) { ecut = std::sqrt(cut); } ecut = (ecut-a) / (p+p); ecut2 = ecut; //JMQ 290310 for avoiding unphysical increase below minimum (at ecut) // ecut<0 means that there is no cut with energy axis, i.e. xs is set // to 0 bellow minimum // if (cut < 0.) ecut2 = ecut - 2.; if (cut < 0.) { ecut2 = ecut; } elab = K * FragmentA / G4double(ResidualA); sig = 0.; if (elab <= ec) { //start for E ecut2) { sig = (p*elab*elab+a*elab+b) * signor; } } //end for EEc sig = (landa*elab+mu+nu/elab) * signor; geom = 0.; if (xnulam < flow || elab < etest) { return sig; } geom = std::sqrt(theA*K); geom = 1.23*ResidualAthrd + ra + 4.573/geom; geom = 31.416 * geom * geom; sig = std::max(geom,sig); } //end for E>Ec return sig; }