Geant4  10.00.p03
G4PreCompoundNeutron.cc
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26 // $Id: G4PreCompoundNeutron.cc 68028 2013-03-13 13:48:15Z gcosmo $
27 //
28 // -------------------------------------------------------------------
29 //
30 // GEANT4 Class file
31 //
32 //
33 // File name: G4PreCompoundNeutron
34 //
35 // Author: V.Lara
36 //
37 // Modified:
38 // 21.08.2008 J. M. Quesada add choice of options
39 // 10.02.2009 J. M. Quesada set default opt3
40 // 20.08.2010 V.Ivanchenko added G4Pow and G4PreCompoundParameters pointers
41 // use int Z and A and cleanup
42 //
43 
44 #include "G4PreCompoundNeutron.hh"
45 #include "G4SystemOfUnits.hh"
46 #include "G4Neutron.hh"
47 
49  : G4PreCompoundNucleon(G4Neutron::Neutron(), &theNeutronCoulombBarrier)
50 {
51  ResidualA = GetRestA();
52  ResidualZ = GetRestZ();
53  theA = GetA();
54  theZ = GetZ();
58 }
59 
61 {}
62 
64 {
65  G4double rj = 0.0;
66  if(nParticles > 0) {
67  rj = static_cast<G4double>(nParticles - nCharged)/
68  static_cast<G4double>(nParticles);
69  }
70  return rj;
71 }
72 
74 //J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
75 //OPT=0 Dostrovski's parameterization
76 //OPT=1,2 Chatterjee's paramaterization
77 //OPT=3,4 Kalbach's parameterization
78 //
80 {
81  ResidualA = GetRestA();
82  ResidualZ = GetRestZ();
83  theA = GetA();
84  theZ = GetZ();
88 
89  if (OPTxs==0) { return GetOpt0( K); }
90  else if( OPTxs==1 || OPTxs==2) { return GetOpt12( K); }
91  else if (OPTxs==3 || OPTxs==4) { return GetOpt34( K); }
92  else{
93  std::ostringstream errOs;
94  errOs << "BAD NEUTRON CROSS SECTION OPTION !!" <<G4endl;
95  throw G4HadronicException(__FILE__, __LINE__, errOs.str());
96  return 0.;
97  }
98 }
99 
101 {
102  return 0.76+2.2/ResidualAthrd;
103 }
104 
106 {
107  // return (2.12/std::pow(GetRestA(),2.0/3.0)-0.05)*MeV/GetAlpha();
108  return (2.12/(ResidualAthrd*ResidualAthrd)-0.05)*MeV/GetAlpha();
109 }
110 
111 //********************* OPT=1,2 : Chatterjee's cross section ***************
112 //(fitting to cross section from Bechetti & Greenles OM potential)
113 
115 {
116  G4double Kc=K;
117 
118  // Pramana (Bechetti & Greenles) for neutrons is chosen
119 
120  // JMQ xsec is set constat above limit of validity
121  if (K > 50*MeV) { Kc = 50*MeV; }
122 
123  G4double landa, landa0, landa1, mu, mm0, mu1,nu, nu0, nu1, nu2,xs;
124 
125  landa0 = 18.57;
126  landa1 = -22.93;
127  mm0 = 381.7;
128  mu1 = 24.31;
129  nu0 = 0.172;
130  nu1 = -15.39;
131  nu2 = 804.8;
132  landa = landa0/ResidualAthrd + landa1;
134  nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2 ;
135  xs=landa*Kc + mu + nu/Kc;
136  if (xs <= 0.0 ){
137  std::ostringstream errOs;
138  G4cout<<"WARNING: NEGATIVE OPT=1 neutron cross section "<<G4endl;
139  errOs << "RESIDUAL: Ar=" << ResidualA << " Zr=" << ResidualZ <<G4endl;
140  errOs <<" xsec("<<Kc<<" MeV) ="<<xs <<G4endl;
141  throw G4HadronicException(__FILE__, __LINE__, errOs.str());
142  }
143  return xs;
144 }
145 
146 // *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
148 {
149  G4double landa, landa0, landa1, mu, mm0, mu1,nu, nu0, nu1, nu2;
150  G4double p, p0;
151  G4double flow,ec,ecsq,xnulam,etest(0.),ra(0.),a,signor(1.),sig;
152  G4double b,ecut,cut,ecut2,geom,elab;
153 
154  flow = 1.e-18;
155 
156  // PRECO xs for neutrons is choosen
157  p0 = -312.;
158  landa0 = 12.10;
159  landa1= -11.27;
160  mm0 = 234.1;
161  mu1 = 38.26;
162  nu0 = 1.55;
163  nu1 = -106.1;
164  nu2 = 1280.8;
165 
166  if (ResidualA < 40) { signor =0.7 + ResidualA*0.0075; }
167  if (ResidualA > 210) { signor = 1. + (ResidualA-210)/250.; }
168  landa = landa0/ResidualAthrd + landa1;
170  nu = nu0*ResidualAthrd*ResidualA + nu1*ResidualAthrd*ResidualAthrd + nu2;
171 
172  // JMQ very low energy behaviour corrected (problem for A (apprx.)>60)
173  if (nu < 0.) { nu=-nu; }
174 
175  ec = 0.5;
176  ecsq = 0.25;
177  p = p0;
178  xnulam = 1.;
179  etest = 32.;
180  // ** etest is the energy above which the rxn cross section is
181  // ** compared with the geometrical limit and the max taken.
182  // ** xnulam here is a dummy value to be used later.
183 
184  a = -2.*p*ec + landa - nu/ecsq;
185  b = p*ecsq + mu + 2.*nu/ec;
186  ecut = 0.;
187  cut = a*a - 4.*p*b;
188  if (cut > 0.) { ecut = std::sqrt(cut); }
189  ecut = (ecut-a) / (p+p);
190  ecut2 = ecut;
191  if (cut < 0.) { ecut2 = ecut - 2.; }
192  elab = K * FragmentA / G4double(ResidualA);
193  sig = 0.;
194  if (elab <= ec) { //start for E<Ec
195  if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; }
196  } //end for E<Ec
197  else { //start for E>Ec
198  sig = (landa*elab+mu+nu/elab) * signor;
199  geom = 0.;
200  if (xnulam < flow || elab < etest) { return sig; }
201  geom = std::sqrt(theA*K);
202  geom = 1.23*ResidualAthrd + ra + 4.573/geom;
203  geom = 31.416 * geom * geom;
204  sig = std::max(geom,sig);
205 
206  }
207  return sig;
208 }
G4double GetOpt12(G4double K)
static const double MeV
Definition: G4SIunits.hh:193
G4double ResidualA13() const
G4double GetOpt34(G4double K)
G4int GetA() const
G4double GetOpt0(G4double ekin)
G4double a
Definition: TRTMaterials.hh:39
int G4int
Definition: G4Types.hh:78
virtual G4double CrossSection(G4double ekin)
G4GLOB_DLL std::ostream G4cout
G4double Z13(G4int Z) const
Definition: G4Pow.hh:129
G4int GetRestZ() const
virtual G4double GetAlpha()
T max(const T t1, const T t2)
brief Return the largest of the two arguments
G4int GetRestA() const
#define G4endl
Definition: G4ios.hh:61
G4int GetZ() const
virtual G4double GetBeta()
double G4double
Definition: G4Types.hh:76
virtual G4double GetRj(G4int NumberParticles, G4int NumberCharged)