source: trunk/source/processes/hadronic/models/pre_equilibrium/exciton_model/src/G4PreCompoundAlpha.cc @ 1337

Last change on this file since 1337 was 1337, checked in by garnier, 14 years ago

tag geant4.9.4 beta 1 + modifs locales
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27// $Id: G4PreCompoundAlpha.cc,v 1.6 2010/04/09 14:06:17 vnivanch Exp $
28// GEANT4 tag $Name: geant4-09-04-beta-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//
42
43#include "G4PreCompoundAlpha.hh"
44
45G4ReactionProduct * G4PreCompoundAlpha::GetReactionProduct() const
46{
47  G4ReactionProduct * theReactionProduct =
48    new G4ReactionProduct(G4Alpha::AlphaDefinition());
49  theReactionProduct->SetMomentum(GetMomentum().vect());
50  theReactionProduct->SetTotalEnergy(GetMomentum().e());
51#ifdef PRECOMPOUND_TEST
52  theReactionProduct->SetCreatorModel("G4PrecompoundModel");
53#endif
54  return theReactionProduct;
55}   
56
57G4double G4PreCompoundAlpha::FactorialFactor(const G4double N, const G4double P)
58{
59  return 
60      (N-4.0)*(P-3.0)*(
61                       (((N-3.0)*(P-2.0))/2.0) *(
62                                                 (((N-2.0)*(P-1.0))/3.0) *(
63                                                                           (((N-1.0)*P)/2.0)
64                                                                           )
65                                                 )
66                       );
67}
68 
69G4double G4PreCompoundAlpha::CoalescenceFactor(const G4double A)
70{
71  return 4096.0/(A*A*A); 
72}   
73
74G4double G4PreCompoundAlpha::GetRj(const G4int NumberParticles, const G4int NumberCharged)
75{
76  G4double rj = 0.0;
77  G4double denominator = NumberParticles*(NumberParticles-1)*(NumberParticles-2)*(NumberParticles-3);
78  if(NumberCharged >=2 && (NumberParticles-NumberCharged) >=2 ) {
79    rj = 6.0*static_cast<G4double>(NumberCharged*(NumberCharged-1)*(NumberParticles-NumberCharged)*
80                                   (NumberParticles-NumberCharged-1))/static_cast<G4double>(denominator); 
81  }
82  return rj;
83}
84
85////////////////////////////////////////////////////////////////////////////////////
86//J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
87//OPT=0 Dostrovski's parameterization
88//OPT=1,2 Chatterjee's paramaterization
89//OPT=3,4 Kalbach's parameterization
90//
91G4double G4PreCompoundAlpha::CrossSection(const  G4double K)
92{
93
94  ResidualA=GetRestA();
95  ResidualZ=GetRestZ(); 
96  theA=GetA();
97  theZ=GetZ();
98  ResidualAthrd=std::pow(ResidualA,0.33333);
99  FragmentA=GetA()+GetRestA();
100  FragmentAthrd=std::pow(FragmentA,0.33333);
101
102
103  if (OPTxs==0) return GetOpt0( K);
104  else if( OPTxs==1 || OPTxs==2) return GetOpt12( K);
105  else if (OPTxs==3 || OPTxs==4)  return GetOpt34( K);
106  else{
107    std::ostringstream errOs;
108    errOs << "BAD Alpha CROSS SECTION OPTION !!"  <<G4endl;
109    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
110    return 0.;
111  }
112}
113
114// *********************** OPT=0 : Dostrovski's cross section  *****************************
115
116G4double G4PreCompoundAlpha::GetOpt0(const  G4double K)
117{
118  const G4double r0 = G4PreCompoundParameters::GetAddress()->Getr0();
119  // cross section is now given in mb (r0 is in mm) for the sake of consistency
120  //with the rest of the options
121  return 1.e+25*pi*(r0*ResidualAthrd)*(r0*ResidualAthrd)*GetAlpha()*(1.+GetBeta()/K);
122}
123//
124//----------------
125//
126G4double G4PreCompoundAlpha::GetAlpha()
127{
128  G4double C = 0.0;
129  G4double aZ = GetZ() + GetRestZ();
130  if (aZ <= 30) 
131    {
132      C = 0.10;
133    } 
134  else if (aZ <= 50) 
135    {
136      C = 0.1 + -((aZ-50.)/20.)*0.02;
137    } 
138  else if (aZ < 70) 
139    {
140      C = 0.08 + -((aZ-70.)/20.)*0.02;
141    }
142  else 
143    {
144      C = 0.06;
145    }
146  return 1.0+C;
147}
148//
149//--------------------
150//
151G4double G4PreCompoundAlpha::GetBeta() 
152{
153  return -GetCoulombBarrier();
154}
155//
156//********************* OPT=1,2 : Chatterjee's cross section ************************
157//(fitting to cross section from Bechetti & Greenles OM potential)
158
159G4double G4PreCompoundAlpha::GetOpt12(const  G4double K)
160{
161
162  G4double Kc=K;
163
164  // JMQ xsec is set constant above limit of validity
165  if (K>50) Kc=50;
166
167  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
168
169  G4double     p0 = 10.95;
170  G4double     p1 = -85.2;
171  G4double     p2 = 1146.;
172  G4double     landa0 = 0.0643;
173  G4double     landa1 = -13.96;
174  G4double     mu0 = 781.2;
175  G4double     mu1 = 0.29;
176  G4double     nu0 = -304.7;
177  G4double     nu1 = -470.0;
178  G4double     nu2 = -8.580;   
179  G4double     delta=1.2;         
180
181  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
182  p = p0 + p1/Ec + p2/(Ec*Ec);
183  landa = landa0*ResidualA + landa1;
184  mu = mu0*std::pow(ResidualA,mu1);
185  nu = std::pow(ResidualA,mu1)*(nu0 + nu1*Ec + nu2*(Ec*Ec));
186  q = landa - nu/(Ec*Ec) - 2*p*Ec;
187  r = mu + 2*nu/Ec + p*(Ec*Ec);
188
189  ji=std::max(Kc,Ec);
190  if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;}
191  else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;}
192 
193  if (xs <0.0) {xs=0.0;}
194             
195  return xs;
196
197}
198
199// *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
200G4double G4PreCompoundAlpha::GetOpt34(const  G4double K)
201// c     ** alpha from huizenga and igo
202{
203
204  G4double landa, mu, nu, p , signor(1.),sig;
205  G4double ec,ecsq,xnulam,etest(0.),a; 
206  G4double b,ecut,cut,ecut2,geom,elab;
207
208  G4double     flow = 1.e-18;
209  G4double     spill= 1.e+18;
210
211  G4double       p0 = 10.95;
212  G4double     p1 = -85.2;
213  G4double     p2 = 1146.;
214  G4double     landa0 = 0.0643;
215  G4double     landa1 = -13.96;
216  G4double     mu0 = 781.2;
217  G4double     mu1 = 0.29;
218  G4double     nu0 = -304.7;
219  G4double     nu1 = -470.0;
220  G4double     nu2 = -8.580;       
221 
222  G4double      ra=1.20;
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//JMQ 290310 for avoiding unphysical increase below minimum (at ecut)
245//ecut<0 means that there is no cut with energy axis, i.e. xs is set to 0 bellow minimum
246//  if (cut < 0.) ecut2 = ecut - 2.;
247  if (cut < 0.) ecut2 = ecut;
248  elab = K * FragmentA / ResidualA;
249  sig = 0.;
250 
251  if (elab <= ec) { //start for E<Ec
252    if (elab > ecut2)  sig = (p*elab*elab+a*elab+b) * signor;
253  }           //end for E<Ec
254  else {           //start for E>Ec
255    sig = (landa*elab+mu+nu/elab) * signor;
256    geom = 0.;
257    if (xnulam < flow || elab < etest) return sig;
258    geom = std::sqrt(theA*K);
259    geom = 1.23*ResidualAthrd + ra + 4.573/geom;
260    geom = 31.416 * geom * geom;
261    sig = std::max(geom,sig);
262  }           //end for E>Ec
263  return sig;
264 
265}
266
267//   ************************** end of cross sections *******************************
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