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G4PreCompoundHe3.cc
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26 // $Id$
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28 // -------------------------------------------------------------------
29 //
30 // GEANT4 Class file
31 //
32 //
33 // File name: G4PreCompoundHe3
34 //
35 // Author: V.Lara
36 //
37 // Modified:
38 // 21.08.2008 J. M. Quesada add choice of options
39 // 20.08.2010 V.Ivanchenko added G4Pow and G4PreCompoundParameters pointers
40 // use int Z and A and cleanup
41 //
42 
43 #include "G4PreCompoundHe3.hh"
44 #include "G4SystemOfUnits.hh"
45 #include "G4He3.hh"
46 
48  : G4PreCompoundIon(G4He3::He3(), &theHe3CoulombBarrier)
49 {
50  ResidualA = GetRestA();
51  ResidualZ = GetRestZ();
52  theA = GetA();
53  theZ = GetZ();
54  ResidualAthrd = ResidualA13();
55  FragmentAthrd = ResidualAthrd;
56  FragmentA = theA + ResidualA;
57 }
58 
60 {}
61 
63 {
64  return G4double((N-3)*(P-2)*(N-2)*(P-1)*(N-1)*P)/6.0;
65 }
66 
68 {
69  return 243.0/G4double(A*A);
70 }
71 
73 {
74  G4double rj = 0.0;
75  if(nCharged >=2 && (nParticles-nCharged) >= 1) {
76  G4double denominator = G4double(nParticles*(nParticles-1)*(nParticles-2));
77  rj = G4double(3*nCharged*(nCharged-1)*(nParticles-nCharged))/denominator;
78  }
79  return rj;
80 }
81 
83 //J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections
84 //OPT=0 Dostrovski's parameterization
85 //OPT=1,2 Chatterjee's paramaterization
86 //OPT=3,4 Kalbach's parameterization
87 //
89 {
90  ResidualA = GetRestA();
91  ResidualZ = GetRestZ();
92  theA = GetA();
93  theZ = GetZ();
94  ResidualAthrd = ResidualA13();
95  FragmentA = theA + ResidualA;
96  FragmentAthrd = g4pow->Z13(FragmentA);
97 
98  if (OPTxs==0) return GetOpt0( K);
99  else if( OPTxs==1 || OPTxs==2) return GetOpt12( K);
100  else if (OPTxs==3 || OPTxs==4) return GetOpt34( K);
101  else{
102  std::ostringstream errOs;
103  errOs << "BAD He3 CROSS SECTION OPTION !!" <<G4endl;
104  throw G4HadronicException(__FILE__, __LINE__, errOs.str());
105  return 0.;
106  }
107 }
108 
110 {
111  G4double C = 0.0;
112  G4int aZ = theZ + ResidualZ;
113  if (aZ <= 30)
114  {
115  C = 0.10;
116  }
117  else if (aZ <= 50)
118  {
119  C = 0.1 - (aZ - 30)*0.001;
120  }
121  else if (aZ < 70)
122  {
123  C = 0.08 - (aZ - 50)*0.001;
124  }
125  else
126  {
127  C = 0.06;
128  }
129  return 1.0 + C*(4.0/3.0);
130 }
131 
132 //********************* OPT=1,2 : Chatterjee's cross section *****************
133 //(fitting to cross section from Bechetti & Greenles OM potential)
134 
136 {
137  G4double Kc = K;
138 
139  // JMQ xsec is set constat above limit of validity
140  if (K > 50*MeV) { Kc = 50*MeV; }
141 
142  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
143 
144  G4double p0 = -3.06;
145  G4double p1 = 278.5;
146  G4double p2 = -1389.;
147  G4double landa0 = -0.00535;
148  G4double landa1 = -11.16;
149  G4double mm0 = 555.5;
150  G4double mu1 = 0.40;
151  G4double nu0 = 687.4;
152  G4double nu1 = -476.3;
153  G4double nu2 = 0.509;
154  G4double delta=1.2;
155 
156  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
157  p = p0 + p1/Ec + p2/(Ec*Ec);
158  landa = landa0*ResidualA + landa1;
159 
160  G4double resmu1 = g4pow->powZ(ResidualA,mu1);
161  mu = mm0*resmu1;
162  nu = resmu1*(nu0 + nu1*Ec + nu2*(Ec*Ec));
163  q = landa - nu/(Ec*Ec) - 2*p*Ec;
164  r = mu + 2*nu/Ec + p*(Ec*Ec);
165 
166  ji=std::max(Kc,Ec);
167  if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;}
168  else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;}
169 
170  if (xs <0.0) {xs=0.0;}
171 
172  return xs;
173 
174 }
175 
176 // *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
178 //c ** 3he from o.m. of gibson et al
179 {
180  G4double landa, mu, nu, p , signor(1.),sig;
181  G4double ec,ecsq,xnulam,etest(0.),a;
182  G4double b,ecut,cut,ecut2,geom,elab;
183 
184  G4double flow = 1.e-18;
185  G4double spill= 1.e+18;
186 
187  G4double p0 = -2.88;
188  G4double p1 = 205.6;
189  G4double p2 = -1487.;
190  G4double landa0 = 0.00459;
191  G4double landa1 = -8.93;
192  G4double mm0 = 611.2;
193  G4double mu1 = 0.35;
194  G4double nu0 = 473.8;
195  G4double nu1 = -468.2;
196  G4double nu2 = -2.225;
197 
198  G4double ra=0.80;
199 
200  //JMQ 13/02/09 increase of reduced radius to lower the barrier
201  // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra);
202  ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra);
203  ecsq = ec * ec;
204  p = p0 + p1/ec + p2/ecsq;
205  landa = landa0*ResidualA + landa1;
206  a = g4pow->powZ(ResidualA,mu1);
207  mu = mm0 * a;
208  nu = a* (nu0+nu1*ec+nu2*ecsq);
209  xnulam = nu / landa;
210  if (xnulam > spill) { xnulam=0.; }
211  if (xnulam >= flow) { etest = 1.2 *std::sqrt(xnulam); }
212 
213  a = -2.*p*ec + landa - nu/ecsq;
214  b = p*ecsq + mu + 2.*nu/ec;
215  ecut = 0.;
216  cut = a*a - 4.*p*b;
217  if (cut > 0.) ecut = std::sqrt(cut);
218  ecut = (ecut-a) / (p+p);
219  ecut2 = ecut;
220  //JMQ 290310 for avoiding unphysical increase below minimum (at ecut)
221  // ecut<0 means that there is no cut with energy axis, i.e. xs is set
222  // to 0 bellow minimum
223  // if (cut < 0.) ecut2 = ecut - 2.;
224  if (cut < 0.) { ecut2 = ecut; }
225  elab = K * FragmentA /G4double(ResidualA);
226  sig = 0.;
227 
228  if (elab <= ec) { //start for E<Ec
229  if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; }
230  } //end for E<Ec
231  else { //start for E>Ec
232  sig = (landa*elab+mu+nu/elab) * signor;
233  geom = 0.;
234  if (xnulam < flow || elab < etest) { return sig; }
235  geom = std::sqrt(theA*K);
236  geom = 1.23*ResidualAthrd + ra + 4.573/geom;
237  geom = 31.416 * geom * geom;
238  sig = std::max(geom,sig);
239  } //end for E>Ec
240  return sig;
241 
242 }