source: trunk/source/processes/hadronic/models/pre_equilibrium/exciton_model/src/G4PreCompoundHe3.cc @ 1340

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26// $Id: G4PreCompoundHe3.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:     G4PreCompoundHe3
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 "G4PreCompoundHe3.hh"
45#include "G4He3.hh"
46
47G4PreCompoundHe3::G4PreCompoundHe3()
48  : G4PreCompoundIon(G4He3::He3(), &theHe3CoulombBarrier)
49{}
50
51G4PreCompoundHe3::~G4PreCompoundHe3()
52{}
53
54G4double G4PreCompoundHe3::FactorialFactor(G4int N, G4int P)
55{
56  return G4double((N-3)*(P-2)*(N-2)*(P-1)*(N-1)*P)/6.0; 
57}
58 
59G4double G4PreCompoundHe3::CoalescenceFactor(G4int A)
60{
61  return 243.0/G4double(A*A);
62}   
63
64G4double G4PreCompoundHe3::GetRj(G4int nParticles, G4int nCharged)
65{
66  G4double rj = 0.0;
67  if(nCharged >=2 && (nParticles-nCharged) >= 1) {
68    G4double denominator = G4double(nParticles*(nParticles-1)*(nParticles-2));
69    rj = G4double(3*nCharged*(nCharged-1)*(nParticles-nCharged))/denominator; 
70  }
71  return rj;
72}
73
74////////////////////////////////////////////////////////////////////////////////
75//J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
76//OPT=0 Dostrovski's parameterization
77//OPT=1,2 Chatterjee's paramaterization
78//OPT=3,4 Kalbach's parameterization
79//
80G4double G4PreCompoundHe3::CrossSection(G4double K)
81{
82  ResidualA = GetRestA();
83  ResidualZ = GetRestZ(); 
84  theA = GetA();
85  theZ = GetZ();
86  ResidualAthrd = ResidualA13();
87  FragmentA = theA + ResidualA;
88  FragmentAthrd = g4pow->Z13(FragmentA);
89
90  if (OPTxs==0) return GetOpt0( K);
91  else if( OPTxs==1 || OPTxs==2) return GetOpt12( K);
92  else if (OPTxs==3 || OPTxs==4)  return GetOpt34( K);
93  else{
94    std::ostringstream errOs;
95    errOs << "BAD He3 CROSS SECTION OPTION !!"  <<G4endl;
96    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
97    return 0.;
98  }
99}
100
101G4double G4PreCompoundHe3::GetAlpha()
102{
103  G4double C = 0.0;
104  G4int aZ = theZ + ResidualZ;
105  if (aZ <= 30) 
106    {
107      C = 0.10;
108    }
109  else if (aZ <= 50) 
110    {
111      C = 0.1 - (aZ - 30)*0.001;
112    } 
113  else if (aZ < 70) 
114    {
115      C = 0.08 - (aZ - 50)*0.001;
116    }
117  else 
118    {
119      C = 0.06;
120    }
121  return 1.0 + C*(4.0/3.0);
122}
123
124//********************* OPT=1,2 : Chatterjee's cross section *****************
125//(fitting to cross section from Bechetti & Greenles OM potential)
126
127G4double G4PreCompoundHe3::GetOpt12(const  G4double K)
128{
129  G4double Kc = K;
130
131  // JMQ xsec is set constat above limit of validity
132  if (K > 50*MeV) { Kc = 50*MeV; }
133
134  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
135
136  G4double     p0 = -3.06;
137  G4double     p1 = 278.5;
138  G4double     p2 = -1389.;
139  G4double     landa0 = -0.00535;
140  G4double     landa1 = -11.16;
141  G4double     mu0 = 555.5;
142  G4double     mu1 = 0.40;
143  G4double     nu0 = 687.4;
144  G4double     nu1 = -476.3;
145  G4double     nu2 = 0.509;   
146  G4double     delta=1.2;             
147
148  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
149  p = p0 + p1/Ec + p2/(Ec*Ec);
150  landa = landa0*ResidualA + landa1;
151
152  G4double resmu1 = g4pow->powZ(ResidualA,mu1); 
153  mu = mu0*resmu1;
154  nu = resmu1*(nu0 + nu1*Ec + nu2*(Ec*Ec));
155  q = landa - nu/(Ec*Ec) - 2*p*Ec;
156  r = mu + 2*nu/Ec + p*(Ec*Ec);
157 
158  ji=std::max(Kc,Ec);
159  if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;}
160  else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;}
161 
162  if (xs <0.0) {xs=0.0;}
163             
164  return xs;
165
166}
167
168// *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
169G4double G4PreCompoundHe3::GetOpt34(const  G4double K)
170//c     ** 3he from o.m. of gibson et al
171{
172  G4double landa, mu, nu, p , signor(1.),sig;
173  G4double ec,ecsq,xnulam,etest(0.),a; 
174  G4double b,ecut,cut,ecut2,geom,elab;
175
176  G4double     flow = 1.e-18;
177  G4double     spill= 1.e+18;
178
179  G4double     p0 = -2.88;
180  G4double     p1 = 205.6;
181  G4double     p2 = -1487.;
182  G4double     landa0 = 0.00459;
183  G4double     landa1 = -8.93;
184  G4double     mu0 = 611.2;
185  G4double     mu1 = 0.35;
186  G4double     nu0 = 473.8;
187  G4double     nu1 = -468.2;
188  G4double     nu2 = -2.225;     
189 
190  G4double      ra=0.80;
191       
192  //JMQ 13/02/09 increase of reduced radius to lower the barrier
193  // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra);
194  ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra);
195  ecsq = ec * ec;
196  p = p0 + p1/ec + p2/ecsq;
197  landa = landa0*ResidualA + landa1;
198  a = g4pow->powZ(ResidualA,mu1);
199  mu = mu0 * a;
200  nu = a* (nu0+nu1*ec+nu2*ecsq); 
201  xnulam = nu / landa;
202  if (xnulam > spill) { xnulam=0.; }
203  if (xnulam >= flow) { etest = 1.2 *std::sqrt(xnulam); }
204 
205  a = -2.*p*ec + landa - nu/ecsq;
206  b = p*ecsq + mu + 2.*nu/ec;
207  ecut = 0.;
208  cut = a*a - 4.*p*b;
209  if (cut > 0.) ecut = std::sqrt(cut);
210  ecut = (ecut-a) / (p+p);
211  ecut2 = ecut;
212  //JMQ 290310 for avoiding unphysical increase below minimum (at ecut)
213  // ecut<0 means that there is no cut with energy axis, i.e. xs is set
214  // to 0 bellow minimum
215  //  if (cut < 0.) ecut2 = ecut - 2.;
216  if (cut < 0.) { ecut2 = ecut; }
217  elab = K * FragmentA / ResidualA;
218  sig = 0.;
219 
220  if (elab <= ec) { //start for E<Ec
221    if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; }
222  }           //end for E<Ec
223  else {           //start for E>Ec
224    sig = (landa*elab+mu+nu/elab) * signor;
225    geom = 0.;
226    if (xnulam < flow || elab < etest) { return sig; }
227    geom = std::sqrt(theA*K);
228    geom = 1.23*ResidualAthrd + ra + 4.573/geom;
229    geom = 31.416 * geom * geom;
230    sig = std::max(geom,sig);
231  }           //end for E>Ec
232  return sig;
233 
234}
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