source: trunk/source/processes/hadronic/models/pre_equilibrium/exciton_model/src/G4PreCompoundHe3.cc @ 968

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27// $Id: G4PreCompoundHe3.cc,v 1.5 2009/02/13 18:57:32 vnivanch Exp $
28// GEANT4 tag $Name: geant4-09-02-ref-02 $
29//
30// -------------------------------------------------------------------
31//
32// GEANT4 Class file
33//
34//
35// File name:     G4PreCompoundHe3
36//
37// Author:         V.Lara
38//
39// Modified: 
40// 21.08.2008 J. M. Quesada add choice of options 
41// 10.02.2009 J. M. Quesada set default opt1 
42//
43 
44#include "G4PreCompoundHe3.hh"
45
46G4ReactionProduct * G4PreCompoundHe3::GetReactionProduct() const
47{
48  G4ReactionProduct * theReactionProduct =
49    new G4ReactionProduct(G4He3::He3Definition());
50  theReactionProduct->SetMomentum(GetMomentum().vect());
51  theReactionProduct->SetTotalEnergy(GetMomentum().e());
52#ifdef PRECOMPOUND_TEST
53  theReactionProduct->SetCreatorModel("G4PrecompoundModel");
54#endif
55  return theReactionProduct;
56}   
57
58G4double G4PreCompoundHe3::FactorialFactor(const G4double N, const G4double P)
59{
60  return 
61      (N-3.0)*(P-2.0)*(
62                       (((N-2.0)*(P-1.0))/2.0) *(
63                                                 (((N-1.0)*P)/3.0) 
64                                                 )
65                       );
66}
67 
68G4double G4PreCompoundHe3::CoalescenceFactor(const G4double A)
69{
70  return 243.0/(A*A);
71}   
72
73G4double G4PreCompoundHe3::GetRj(const G4int NumberParticles, const G4int NumberCharged)
74{
75  G4double rj = 0.0;
76  G4double denominator = NumberParticles*(NumberParticles-1)*(NumberParticles-2);
77  if(NumberCharged >=2 && (NumberParticles-NumberCharged) >= 1) {
78    rj = 3.0*static_cast<G4double>(NumberCharged*(NumberCharged-1)*(NumberParticles-NumberCharged))
79      / static_cast<G4double>(denominator); 
80  }
81  return rj;
82}
83
84////////////////////////////////////////////////////////////////////////////////////
85//J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
86//OPT=0 Dostrovski's parameterization
87//OPT=1,2 Chatterjee's paramaterization
88//OPT=3,4 Kalbach's parameterization
89//
90G4double G4PreCompoundHe3::CrossSection(const  G4double K)
91{
92  ResidualA=GetRestA();
93  ResidualZ=GetRestZ(); 
94  theA=GetA();
95  theZ=GetZ();
96  ResidualAthrd=std::pow(ResidualA,0.33333);
97  FragmentA=GetA()+GetRestA();
98  FragmentAthrd=std::pow(FragmentA,0.33333);
99
100
101  if (OPTxs==0) return GetOpt0( K);
102  else if( OPTxs==1 || OPTxs==2) return GetOpt12( K);
103  else if (OPTxs==3 || OPTxs==4)  return GetOpt34( K);
104  else{
105    std::ostringstream errOs;
106    errOs << "BAD He3 CROSS SECTION OPTION !!"  <<G4endl;
107    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
108    return 0.;
109  }
110}
111
112// *********************** OPT=0 : Dostrovski's cross section  *****************************
113
114G4double G4PreCompoundHe3::GetOpt0(const  G4double K)
115{
116  const G4double r0 = G4PreCompoundParameters::GetAddress()->Getr0();
117  // cross section is now given in mb (r0 is in mm) for the sake of consistency
118  //with the rest of the options
119  return 1.e+25*pi*(r0*ResidualAthrd)*(r0*ResidualAthrd)*GetAlpha()*(1.+GetBeta()/K);
120}
121//
122//----------------
123//
124G4double G4PreCompoundHe3::GetAlpha()
125{
126  G4double C = 0.0;
127  G4double aZ = GetZ() + GetRestZ();
128  if (aZ <= 30) 
129    {
130      C = 0.10;
131    }
132  else if (aZ <= 50) 
133    {
134      C = 0.1 + -((aZ-50.)/20.)*0.02;
135    } 
136  else if (aZ < 70) 
137    {
138      C = 0.08 + -((aZ-70.)/20.)*0.02;
139    }
140  else 
141    {
142      C = 0.06;
143    }
144  return 1.0 + C*(4.0/3.0);
145}
146//
147//--------------------
148//
149G4double G4PreCompoundHe3::GetBeta() 
150{
151  return -GetCoulombBarrier();
152}
153//
154//********************* OPT=1,2 : Chatterjee's cross section ************************
155//(fitting to cross section from Bechetti & Greenles OM potential)
156
157G4double G4PreCompoundHe3::GetOpt12(const  G4double K)
158{
159
160  G4double Kc=K;
161
162  // JMQ xsec is set constat above limit of validity
163  if (K>50) Kc=50;
164
165  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
166
167  G4double      p0 = -3.06;
168  G4double     p1 = 278.5;
169  G4double     p2 = -1389.;
170  G4double     landa0 = -0.00535;
171  G4double     landa1 = -11.16;
172  G4double     mu0 = 555.5;
173  G4double     mu1 = 0.40;
174  G4double     nu0 = 687.4;
175  G4double     nu1 = -476.3;
176  G4double     nu2 = 0.509;   
177  G4double     delta=1.2;             
178
179  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
180  p = p0 + p1/Ec + p2/(Ec*Ec);
181  landa = landa0*ResidualA + landa1;
182  mu = mu0*std::pow(ResidualA,mu1);
183  nu = std::pow(ResidualA,mu1)*(nu0 + nu1*Ec + nu2*(Ec*Ec));
184  q = landa - nu/(Ec*Ec) - 2*p*Ec;
185  r = mu + 2*nu/Ec + p*(Ec*Ec);
186 
187  ji=std::max(Kc,Ec);
188  if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;}
189  else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;}
190 
191  if (xs <0.0) {xs=0.0;}
192             
193  return xs;
194
195}
196
197// *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
198G4double G4PreCompoundHe3::GetOpt34(const  G4double K)
199//c     ** 3he from o.m. of gibson et al
200{
201
202  G4double landa, mu, nu, p , signor(1.),sig;
203  G4double ec,ecsq,xnulam,etest(0.),a; 
204  G4double b,ecut,cut,ecut2,geom,elab;
205
206
207  G4double     flow = 1.e-18;
208  G4double     spill= 1.e+18;
209
210
211  G4double     p0 = -2.88;
212  G4double     p1 = 205.6;
213  G4double     p2 = -1487.;
214  G4double     landa0 = 0.00459;
215  G4double     landa1 = -8.93;
216  G4double     mu0 = 611.2;
217  G4double     mu1 = 0.35;
218  G4double     nu0 = 473.8;
219  G4double     nu1 = -468.2;
220  G4double     nu2 = -2.225;     
221 
222  G4double      ra=0.80;
223       
224  //JMQ 13/02/09 increase of reduced radius to lower the barrier
225  // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra);
226  ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra);
227  ecsq = ec * ec;
228  p = p0 + p1/ec + p2/ecsq;
229  landa = landa0*ResidualA + landa1;
230  a = std::pow(ResidualA,mu1);
231  mu = mu0 * a;
232  nu = a* (nu0+nu1*ec+nu2*ecsq); 
233  xnulam = nu / landa;
234  if (xnulam > spill) xnulam=0.;
235  if (xnulam >= flow) etest = 1.2 *std::sqrt(xnulam);
236 
237  a = -2.*p*ec + landa - nu/ecsq;
238  b = p*ecsq + mu + 2.*nu/ec;
239  ecut = 0.;
240  cut = a*a - 4.*p*b;
241  if (cut > 0.) ecut = std::sqrt(cut);
242  ecut = (ecut-a) / (p+p);
243  ecut2 = ecut;
244  if (cut < 0.) ecut2 = ecut - 2.;
245  elab = K * FragmentA / ResidualA;
246  sig = 0.;
247 
248  if (elab <= ec) { //start for E<Ec
249    if (elab > ecut2)  sig = (p*elab*elab+a*elab+b) * signor;
250  }           //end for E<Ec
251  else {           //start for E>Ec
252    sig = (landa*elab+mu+nu/elab) * signor;
253    geom = 0.;
254    if (xnulam < flow || elab < etest) return sig;
255    geom = std::sqrt(theA*K);
256    geom = 1.23*ResidualAthrd + ra + 4.573/geom;
257    geom = 31.416 * geom * geom;
258    sig = std::max(geom,sig);
259  }           //end for E>Ec
260  return sig;
261 
262}
263
264//   ************************** end of cross sections *******************************
265
266
267
268
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