source: trunk/source/processes/hadronic/models/pre_equilibrium/exciton_model/src/G4PreCompoundTriton.cc

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26// $Id: G4PreCompoundTriton.cc,v 1.7 2010/08/28 15:16:55 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-03-ref-09 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class file
32//
33//
34// File name:     G4PreCompoundTriton
35//
36// Author:         V.Lara
37//
38// Modified: 
39// 21.08.2008 J. M. Quesada add choice of options 
40// 20.08.2010 V.Ivanchenko added G4Pow and G4PreCompoundParameters pointers
41//                         use int Z and A and cleanup
42//
43 
44#include "G4PreCompoundTriton.hh"
45#include "G4Triton.hh"
46
47G4PreCompoundTriton::G4PreCompoundTriton()
48  : G4PreCompoundIon(G4Triton::Triton(), &theTritonCoulombBarrier)
49{}
50
51G4PreCompoundTriton::~G4PreCompoundTriton()
52{}
53
54G4double G4PreCompoundTriton::FactorialFactor(G4int N, const G4int P)
55{
56  return G4double((N-3)*(P-2)*(N-2)*(P-1)*(N-1)*P)/6.0; 
57}
58 
59G4double G4PreCompoundTriton::CoalescenceFactor(G4int A)
60{
61  return 243.0/G4double(A*A);
62}   
63
64G4double G4PreCompoundTriton::GetRj(G4int nParticles, G4int nCharged)
65{
66  G4double rj = 0.0;
67  if(nCharged >= 1 && (nParticles-nCharged) >= 2) {
68    G4double denominator = 
69      G4double(nParticles*(nParticles-1)*(nParticles-2));
70    rj = G4double(3*nCharged*(nParticles-nCharged)*(nParticles-nCharged-1))
71      /denominator; 
72  }
73  return rj;
74}
75
76//////////////////////////////////////////////////////////////////////////////////
77//J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
78//OPT=0 Dostrovski's parameterization
79//OPT=1,2 Chatterjee's paramaterization
80//OPT=3,4 Kalbach's parameterization
81//
82G4double G4PreCompoundTriton::CrossSection(G4double K)
83{
84  ResidualA = GetRestA();
85  ResidualZ = GetRestZ(); 
86  theA = GetA();
87  theZ = GetZ();
88  ResidualAthrd = ResidualA13();
89  FragmentA = theA + ResidualA;
90  FragmentAthrd = g4pow->Z13(FragmentA);
91
92  if (OPTxs==0) { return GetOpt0( K); }
93  else if( OPTxs==1 || OPTxs==2) { return GetOpt12( K); }
94  else if (OPTxs==3 || OPTxs==4) { return GetOpt34( K); }
95  else{
96    std::ostringstream errOs;
97    errOs << "BAD TRITON CROSS SECTION OPTION !!"  <<G4endl;
98    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
99    return 0.;
100  }
101}
102
103G4double G4PreCompoundTriton::GetAlpha()
104{
105  G4double C = 0.0;
106  G4int aZ = theZ + ResidualZ;
107  if (aZ >= 70) 
108    {
109      C = 0.10;
110    } 
111  else 
112    {
113      C = ((((0.15417e-06*aZ) - 0.29875e-04)*aZ + 0.21071e-02)*aZ - 0.66612e-01)*aZ + 0.98375; 
114    }
115 
116  return 1.0 + C/3.0;
117}
118
119//
120//********************* OPT=1,2 : Chatterjee's cross section *****************
121//(fitting to cross section from Bechetti & Greenles OM potential)
122
123G4double G4PreCompoundTriton::GetOpt12(G4double K)
124{
125  G4double Kc=K;
126
127  // JMQ xsec is set constat above limit of validity
128  if (K > 50*MeV) { Kc=50*MeV; }
129
130  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
131 
132  G4double    p0 = -11.04;
133  G4double    p1 = 619.1;
134  G4double    p2 = -2147.;
135  G4double    landa0 = -0.0426;
136  G4double    landa1 = -10.33;
137  G4double    mu0 = 601.9;
138  G4double    mu1 = 0.37;
139  G4double    nu0 = 583.0;
140  G4double    nu1 = -546.2;
141  G4double    nu2 = 1.718; 
142  G4double    delta=1.2;           
143
144  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
145  p = p0 + p1/Ec + p2/(Ec*Ec);
146  landa = landa0*ResidualA + landa1;
147
148  G4double resmu1 = g4pow->powZ(ResidualA,mu1); 
149  mu = mu0*resmu1;
150  nu = resmu1*(nu0 + nu1*Ec + nu2*(Ec*Ec));
151  q = landa - nu/(Ec*Ec) - 2*p*Ec;
152  r = mu + 2*nu/Ec + p*(Ec*Ec);
153 
154  ji=std::max(Kc,Ec);
155  if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;}
156  else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;}
157                 
158  if (xs <0.0) {xs=0.0;}
159             
160  return xs;
161}
162
163// *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
164G4double G4PreCompoundTriton::GetOpt34(G4double K)
165//     ** t from o.m. of hafele, flynn et al
166{
167  G4double landa, mu, nu, p , signor(1.),sig;
168  G4double ec,ecsq,xnulam,etest(0.),a; 
169  G4double b,ecut,cut,ecut2,geom,elab;
170
171  G4double     flow = 1.e-18;
172  G4double     spill= 1.e+18;
173
174  G4double     p0 = -21.45;
175  G4double     p1 = 484.7;
176  G4double     p2 = -1608.;
177  G4double     landa0 = 0.0186;
178  G4double     landa1 = -8.90;
179  G4double     mu0 = 686.3;
180  G4double     mu1 = 0.325;
181  G4double     nu0 = 368.9;
182  G4double     nu1 = -522.2;
183  G4double     nu2 = -4.998; 
184 
185  G4double      ra=0.80;
186       
187  //JMQ 13/02/09 increase of reduced radius to lower the barrier
188  // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra);
189  ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra);
190  ecsq = ec * ec;
191  p = p0 + p1/ec + p2/ecsq;
192  landa = landa0*ResidualA + landa1;
193  a = g4pow->powZ(ResidualA,mu1);
194  mu = mu0 * a;
195  nu = a* (nu0+nu1*ec+nu2*ecsq); 
196  xnulam = nu / landa;
197  if (xnulam > spill) { xnulam=0.; }
198  if (xnulam >= flow) { etest = 1.2 *std::sqrt(xnulam); }
199 
200  a = -2.*p*ec + landa - nu/ecsq;
201  b = p*ecsq + mu + 2.*nu/ec;
202  ecut = 0.;
203  cut = a*a - 4.*p*b;
204  if (cut > 0.) { ecut = std::sqrt(cut); }
205  ecut = (ecut-a) / (p+p);
206  ecut2 = ecut;
207  //JMQ 290310 for avoiding unphysical increase below minimum (at ecut)
208  // ecut<0 means that there is no cut with energy axis, i.e. xs is set
209  // to 0 bellow minimum
210  //  if (cut < 0.) ecut2 = ecut - 2.;
211  if (cut < 0.) { ecut2 = ecut; }
212  elab = K * FragmentA / G4double(ResidualA);
213  sig = 0.;
214 
215  if (elab <= ec) { //start for E<Ec
216    if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; }
217  }           //end for E<Ec
218  else {           //start for E>Ec
219    sig = (landa*elab+mu+nu/elab) * signor;
220    geom = 0.;
221    if (xnulam < flow || elab < etest) { return sig; }
222    geom = std::sqrt(theA*K);
223    geom = 1.23*ResidualAthrd + ra + 4.573/geom;
224    geom = 31.416 * geom * geom;
225    sig = std::max(geom,sig);
226  }           //end for E>Ec
227  return sig;
228}
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