Geant4  10.00.p02
G4NeutronEvaporationProbability.cc
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26 // $Id: G4NeutronEvaporationProbability.cc 67983 2013-03-13 10:42:03Z gcosmo $
27 //
28 // J.M. Quesada (August2008). Based on:
29 //
30 // Hadronic Process: Nuclear De-excitations
31 // by V. Lara (Oct 1998)
32 //
33 // Modified:
34 // 03-09-2008 J.M. Quesada for external choice of inverse cross section option
35 // 17-11-2010 V.Ivanchenko integer Z and A
36 
38 #include "G4SystemOfUnits.hh"
39 
41  G4EvaporationProbability(1,0,2,&theCoulombBarrier) // A,Z,Gamma,&theCoulombBarrier
42 {
45 }
46 
48 {}
49 
51 {
52  return 0.76+2.2/fG4pow->Z13(fragment.GetA_asInt()-GetA());
53 }
54 
56 {
57  return (2.12/fG4pow->Z23(fragment.GetA_asInt()-GetA()) - 0.05)*MeV/
58  CalcAlphaParam(fragment);
59 }
60 
62 //J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
63 //OPT=0 Dostrovski's parameterization
64 //OPT=1,2 Chatterjee's paramaterization
65 //OPT=3,4 Kalbach's parameterization
66 //
67 G4double
69 {
70  theA=GetA();
71  theZ=GetZ();
72  ResidualA=fragment.GetA_asInt()-theA;
73  ResidualZ=fragment.GetZ_asInt()-theZ;
74 
76  FragmentA=fragment.GetA_asInt();
78 
79  if (OPTxs==0) {std::ostringstream errOs;
80  errOs << "We should'n be here (OPT =0) at evaporation cross section calculation (neutrons)!!" <<G4endl;
81  throw G4HadronicException(__FILE__, __LINE__, errOs.str());
82  return 0.;}
83  else if( OPTxs==1 ||OPTxs==2) return GetOpt12( K);
84  else if (OPTxs==3 || OPTxs==4) return GetOpt34( K);
85  else{
86  std::ostringstream errOs;
87  errOs << "BAD NEUTRON CROSS SECTION OPTION AT EVAPORATION!!" <<G4endl;
88  throw G4HadronicException(__FILE__, __LINE__, errOs.str());
89  return 0.;
90  }
91 }
92 
93 //********************* OPT=1,2 : Chatterjee's cross section ***************
94 //(fitting to cross section from Bechetti & Greenles OM potential)
95 
97 {
98  G4double Kc=K;
99 
100  // Pramana (Bechetti & Greenles) for neutrons is chosen
101 
102  // JMQ xsec is set constat above limit of validity
103  if (K > 50*MeV) { Kc = 50*MeV; }
104 
105  G4double landa, landa0, landa1, mu, mum0, mu1,nu, nu0, nu1, nu2,xs;
106 
107  landa0 = 18.57;
108  landa1 = -22.93;
109  mum0 = 381.7;
110  mu1 = 24.31;
111  nu0 = 0.172;
112  nu1 = -15.39;
113  nu2 = 804.8;
114  landa = landa0/ResidualAthrd + landa1;
115  mu = mum0*ResidualAthrd + mu1*ResidualAthrd*ResidualAthrd;
116  nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2 ;
117  xs=landa*Kc + mu + nu/Kc;
118  if (xs <= 0.0 ){
119  std::ostringstream errOs;
120  G4cout<<"WARNING: NEGATIVE OPT=1 neutron cross section "<<G4endl;
121  errOs << "RESIDUAL: Ar=" << ResidualA << " Zr=" << ResidualZ <<G4endl;
122  errOs <<" xsec("<<Kc<<" MeV) ="<<xs <<G4endl;
123  throw G4HadronicException(__FILE__, __LINE__, errOs.str());
124  }
125  return xs;
126 }
127 
128 // *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
130 {
131  G4double landa, landa0, landa1, mu, mum0, mu1,nu, nu0, nu1, nu2;
132  G4double p, p0;
133  G4double flow,ec,ecsq,xnulam,etest(0.),ra(0.),a,signor(1.),sig;
134  G4double b,ecut,cut,ecut2,geom,elab;
135 
136  //safety initialization
137  landa0=0;
138  landa1=0;
139  mum0=0.;
140  mu1=0.;
141  nu0=0.;
142  nu1=0.;
143  nu2=0.;
144  p0=0.;
145 
146  flow = 1.e-18;
147 
148  // PRECO xs for neutrons is choosen
149  p0 = -312.;
150  landa0 = 12.10;
151  landa1= -11.27;
152  mum0 = 234.1;
153  mu1 = 38.26;
154  nu0 = 1.55;
155  nu1 = -106.1;
156  nu2 = 1280.8;
157 
158  if (ResidualA < 40) { signor =0.7 + ResidualA*0.0075; }
159  if (ResidualA > 210) { signor = 1. + (ResidualA-210)/250.; }
160  landa = landa0/ResidualAthrd + landa1;
161  mu = mum0*ResidualAthrd + mu1*ResidualAthrd*ResidualAthrd;
162  nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2;
163 
164  // JMQ very low energy behaviour corrected (problem for A (apprx.)>60)
165  if (nu < 0.) { nu=-nu; }
166 
167  ec = 0.5;
168  ecsq = 0.25;
169  p = p0;
170  xnulam = 1.;
171  etest = 32.;
172  // ** etest is the energy above which the rxn cross section is
173  // ** compared with the geometrical limit and the max taken.
174  // ** xnulam here is a dummy value to be used later.
175 
176  a = -2.*p*ec + landa - nu/ecsq;
177  b = p*ecsq + mu + 2.*nu/ec;
178  ecut = 0.;
179  cut = a*a - 4.*p*b;
180  if (cut > 0.) { ecut = std::sqrt(cut); }
181  ecut = (ecut-a) / (p+p);
182  ecut2 = ecut;
183  if (cut < 0.) { ecut2 = ecut - 2.; }
184  elab = K * FragmentA / G4double(ResidualA);
185  sig = 0.;
186  if (elab <= ec) { //start for E<Ec
187  if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; }
188  } //end for E<Ec
189  else { //start for E>Ec
190  sig = (landa*elab+mu+nu/elab) * signor;
191  geom = 0.;
192  if (xnulam < flow || elab < etest) { return sig; }
193  geom = std::sqrt(theA*K);
194  geom = 1.23*ResidualAthrd + ra + 4.573/geom;
195  geom = 31.416 * geom * geom;
196  sig = std::max(geom,sig);
197 
198  }
199  return sig;
200 }
201 
static const double MeV
Definition: G4SIunits.hh:193
virtual G4double CalcBetaParam(const G4Fragment &fragment)
virtual G4double CrossSection(const G4Fragment &fragment, G4double K)
G4double a
Definition: TRTMaterials.hh:39
virtual G4double CalcAlphaParam(const G4Fragment &fragment)
G4GLOB_DLL std::ostream G4cout
G4double Z13(G4int Z) const
Definition: G4Pow.hh:129
G4int GetA_asInt() const
Definition: G4Fragment.hh:238
T max(const T t1, const T t2)
brief Return the largest of the two arguments
G4int GetZ_asInt() const
Definition: G4Fragment.hh:243
G4double Z23(G4int Z) const
Definition: G4Pow.hh:153
#define G4endl
Definition: G4ios.hh:61
double G4double
Definition: G4Types.hh:76