source: trunk/source/processes/hadronic/models/pre_equilibrium/exciton_model/src/G4PreCompoundAlpha.cc @ 1196

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update CVS release candidate geant4.9.3.01
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27// $Id: G4PreCompoundAlpha.cc,v 1.5 2009/02/13 18:57:32 vnivanch Exp $
28// GEANT4 tag $Name: geant4-09-03-cand-01 $
29//
30// -------------------------------------------------------------------
31//
32// GEANT4 Class file
33//
34//
35// File name:     G4PreCompoundAlpha
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 "G4PreCompoundAlpha.hh"
45
46G4ReactionProduct * G4PreCompoundAlpha::GetReactionProduct() const
47{
48  G4ReactionProduct * theReactionProduct =
49    new G4ReactionProduct(G4Alpha::AlphaDefinition());
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 G4PreCompoundAlpha::FactorialFactor(const G4double N, const G4double P)
59{
60  return 
61      (N-4.0)*(P-3.0)*(
62                       (((N-3.0)*(P-2.0))/2.0) *(
63                                                 (((N-2.0)*(P-1.0))/3.0) *(
64                                                                           (((N-1.0)*P)/2.0)
65                                                                           )
66                                                 )
67                       );
68}
69 
70G4double G4PreCompoundAlpha::CoalescenceFactor(const G4double A)
71{
72  return 4096.0/(A*A*A); 
73}   
74
75G4double G4PreCompoundAlpha::GetRj(const G4int NumberParticles, const G4int NumberCharged)
76{
77  G4double rj = 0.0;
78  G4double denominator = NumberParticles*(NumberParticles-1)*(NumberParticles-2)*(NumberParticles-3);
79  if(NumberCharged >=2 && (NumberParticles-NumberCharged) >=2 ) {
80    rj = 6.0*static_cast<G4double>(NumberCharged*(NumberCharged-1)*(NumberParticles-NumberCharged)*
81                                   (NumberParticles-NumberCharged-1))/static_cast<G4double>(denominator); 
82  }
83  return rj;
84}
85
86////////////////////////////////////////////////////////////////////////////////////
87//J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
88//OPT=0 Dostrovski's parameterization
89//OPT=1,2 Chatterjee's paramaterization
90//OPT=3,4 Kalbach's parameterization
91//
92G4double G4PreCompoundAlpha::CrossSection(const  G4double K)
93{
94
95  ResidualA=GetRestA();
96  ResidualZ=GetRestZ(); 
97  theA=GetA();
98  theZ=GetZ();
99  ResidualAthrd=std::pow(ResidualA,0.33333);
100  FragmentA=GetA()+GetRestA();
101  FragmentAthrd=std::pow(FragmentA,0.33333);
102
103
104  if (OPTxs==0) return GetOpt0( K);
105  else if( OPTxs==1 || OPTxs==2) return GetOpt12( K);
106  else if (OPTxs==3 || OPTxs==4)  return GetOpt34( K);
107  else{
108    std::ostringstream errOs;
109    errOs << "BAD Alpha CROSS SECTION OPTION !!"  <<G4endl;
110    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
111    return 0.;
112  }
113}
114
115// *********************** OPT=0 : Dostrovski's cross section  *****************************
116
117G4double G4PreCompoundAlpha::GetOpt0(const  G4double K)
118{
119  const G4double r0 = G4PreCompoundParameters::GetAddress()->Getr0();
120  // cross section is now given in mb (r0 is in mm) for the sake of consistency
121  //with the rest of the options
122  return 1.e+25*pi*(r0*ResidualAthrd)*(r0*ResidualAthrd)*GetAlpha()*(1.+GetBeta()/K);
123}
124//
125//----------------
126//
127G4double G4PreCompoundAlpha::GetAlpha()
128{
129  G4double C = 0.0;
130  G4double aZ = GetZ() + GetRestZ();
131  if (aZ <= 30) 
132    {
133      C = 0.10;
134    } 
135  else if (aZ <= 50) 
136    {
137      C = 0.1 + -((aZ-50.)/20.)*0.02;
138    } 
139  else if (aZ < 70) 
140    {
141      C = 0.08 + -((aZ-70.)/20.)*0.02;
142    }
143  else 
144    {
145      C = 0.06;
146    }
147  return 1.0+C;
148}
149//
150//--------------------
151//
152G4double G4PreCompoundAlpha::GetBeta() 
153{
154  return -GetCoulombBarrier();
155}
156//
157//********************* OPT=1,2 : Chatterjee's cross section ************************
158//(fitting to cross section from Bechetti & Greenles OM potential)
159
160G4double G4PreCompoundAlpha::GetOpt12(const  G4double K)
161{
162
163  G4double Kc=K;
164
165  // JMQ xsec is set constant above limit of validity
166  if (K>50) Kc=50;
167
168  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
169
170  G4double     p0 = 10.95;
171  G4double     p1 = -85.2;
172  G4double     p2 = 1146.;
173  G4double     landa0 = 0.0643;
174  G4double     landa1 = -13.96;
175  G4double     mu0 = 781.2;
176  G4double     mu1 = 0.29;
177  G4double     nu0 = -304.7;
178  G4double     nu1 = -470.0;
179  G4double     nu2 = -8.580;   
180  G4double     delta=1.2;         
181
182  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
183  p = p0 + p1/Ec + p2/(Ec*Ec);
184  landa = landa0*ResidualA + landa1;
185  mu = mu0*std::pow(ResidualA,mu1);
186  nu = std::pow(ResidualA,mu1)*(nu0 + nu1*Ec + nu2*(Ec*Ec));
187  q = landa - nu/(Ec*Ec) - 2*p*Ec;
188  r = mu + 2*nu/Ec + p*(Ec*Ec);
189
190  ji=std::max(Kc,Ec);
191  if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;}
192  else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;}
193 
194  if (xs <0.0) {xs=0.0;}
195             
196  return xs;
197
198}
199
200// *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
201G4double G4PreCompoundAlpha::GetOpt34(const  G4double K)
202// c     ** alpha from huizenga and igo
203{
204
205  G4double landa, mu, nu, p , signor(1.),sig;
206  G4double ec,ecsq,xnulam,etest(0.),a; 
207  G4double b,ecut,cut,ecut2,geom,elab;
208
209  G4double     flow = 1.e-18;
210  G4double     spill= 1.e+18;
211
212  G4double       p0 = 10.95;
213  G4double     p1 = -85.2;
214  G4double     p2 = 1146.;
215  G4double     landa0 = 0.0643;
216  G4double     landa1 = -13.96;
217  G4double     mu0 = 781.2;
218  G4double     mu1 = 0.29;
219  G4double     nu0 = -304.7;
220  G4double     nu1 = -470.0;
221  G4double     nu2 = -8.580;       
222 
223  G4double      ra=1.20;
224       
225  //JMQ 13/02/09 increase of reduced radius to lower the barrier
226  // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra);
227  ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra);
228  ecsq = ec * ec;
229  p = p0 + p1/ec + p2/ecsq;
230  landa = landa0*ResidualA + landa1;
231  a = std::pow(ResidualA,mu1);
232  mu = mu0 * a;
233  nu = a* (nu0+nu1*ec+nu2*ecsq); 
234  xnulam = nu / landa;
235  if (xnulam > spill) xnulam=0.;
236  if (xnulam >= flow) etest = 1.2 *std::sqrt(xnulam);
237
238  a = -2.*p*ec + landa - nu/ecsq;
239  b = p*ecsq + mu + 2.*nu/ec;
240  ecut = 0.;
241  cut = a*a - 4.*p*b;
242  if (cut > 0.) ecut = std::sqrt(cut);
243  ecut = (ecut-a) / (p+p);
244  ecut2 = ecut;
245  if (cut < 0.) ecut2 = ecut - 2.;
246  elab = K * FragmentA / ResidualA;
247  sig = 0.;
248 
249  if (elab <= ec) { //start for E<Ec
250    if (elab > ecut2)  sig = (p*elab*elab+a*elab+b) * signor;
251  }           //end for E<Ec
252  else {           //start for E>Ec
253    sig = (landa*elab+mu+nu/elab) * signor;
254    geom = 0.;
255    if (xnulam < flow || elab < etest) return sig;
256    geom = std::sqrt(theA*K);
257    geom = 1.23*ResidualAthrd + ra + 4.573/geom;
258    geom = 31.416 * geom * geom;
259    sig = std::max(geom,sig);
260  }           //end for E>Ec
261  return sig;
262 
263}
264
265//   ************************** end of cross sections *******************************
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