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G4KalbachCrossSection.hh
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27 // $Id: G4KalbachCrossSection.hh 66241 2012-12-13 18:34:42Z gunter $
28 //
29 // V.Ivanchenko 13.04.2015
30 //
31 // J.M. Quesada 22.04.2015 several fixes
32 
33 #ifndef G4KalbachCrossSection_h
34 #define G4KalbachCrossSection_h 1
35 
36 #include "globals.hh"
37 #include "G4Exp.hh"
38 #include "G4Pow.hh"
39 
40 //from subroutine sigpar of PRECO-2000 by Constance Kalbach Walker
41 // Calculate optical model reaction cross sections
42 // using the empirical parameterization
43 // of Narasimha Murthy, Chaterjee, and Gupta
44 // going over to the geometrical limit at high energy.
45 //
46 // Proton cross sections scaled down with signor for a<100
47 // (appropriate for becchetti-greenlees potential).
48 // p2 reduced and global red'n factor introduced below Bc
49 // Neutron cross sections scaled down with signor for a<40
50 // Scaled up for A>210 (added June '98 to conform with
51 // my published papers)
52 // (appropriate for Mani et al potential)
53 //
54 
55 // index: 0-neutron, 1-proton, 2-deuteron, 3-triton, 4-He3, 5-He4
56 // parameters: p0, p1, p2, lambda0, lambda1, mu0, mu1, nu0, nu1, nu2, ra
57 
58 static const G4double paramK[6][11] = {
59 // n from mani, melkanoff and iori
60  {-312., 0., 0., 12.10, -11.27, 234.1, 38.26, 1.55, -106.1, 1280.8, 0.0},
61 // p from becchetti and greenlees (but modified with sub-barrier
62 // correction function and p2 changed from -449)
63  {15.72, 9.65, -300., 0.00437,-16.58, 244.7, 0.503, 273.1, -182.4, -1.872, 0.0},
64 // d from o.m. of perey and perey
65  {0.798, 420.3,-1651., 0.00619, -7.54, 583.5, 0.337, 421.8, -474.5, -3.592, 0.8},
66 // t from o.m. of hafele, flynn et al
67  {-21.45,484.7,-1608., 0.0186, -8.9, 686.3, 0.325, 368.9, -522.2, -4.998, 0.8},
68 // 3he from o.m. of gibson et al
69  {-2.88,205.6, -1487.,0.00459,-8.93, 611.2, 0.35 , 473.8, -468.2, -2.225, 0.8},
70 // alpha from huizenga and igo
71  { 10.95,-85.2, 1146., 0.0643,-13.96, 781.2, 0.29, -304.7,-470.0, -8.580, 1.2}
72 };
73 
75 {
76 public:
77 
79  {
80  return G4Pow::GetInstance()->powZ(resA, paramK[idx][6]);
81  }
82 
84  G4double resA13, G4double amu1,
85  G4int idx, G4int Z, G4int A,
86  G4int resA)
87  {
88  G4double sig = 0.0;
89  G4double signor = 1.0;
90  G4double lambda, mu, nu;
91  G4double ec = 0.5;
92  if(0 < Z) { ec = cb; }
93  //JMQ 13.02.2009 tuning for improving cluster emission ddxs
94  // (spallation benchmark)
95  /*
96  G4double xx = 1.7;
97  if(1 == A) { xx = 1.5; }
98  ec = 1.44 * Z * resZ / (xx*resA13 + paramK[idx][10]);
99  }
100  */
101  G4double ecsq = ec*ec;
102  G4double elab = K * (A + resA) / G4double(resA);
103 
104  if(idx == 0) { // parameterization for neutron
105 
106  if(resA < 40) { signor =0.7 + resA*0.0075; }
107  else if(resA > 210) { signor = 1. + (resA-210)*0.004; }
108  lambda = paramK[idx][3]/resA13 + paramK[idx][4];
109  mu = (paramK[idx][5] + paramK[idx][6]*resA13)*resA13;
110  // JMQ 20.11.2008 very low energy behaviour corrected
111  // (problem for A (apprx.)>60) fix for avoiding
112  // neutron xs going to zero at very low energies
113  nu = std::abs((paramK[idx][7]*resA + paramK[idx][8]*resA13)*resA13
114  + paramK[idx][9]);
115 
116  } else { // parameterization for charged
117  // proton correction
118  if(idx == 1) {
119  if (resA <= 60) { signor = 0.92; }
120  else if (resA < 100) { signor = 0.8 + resA*0.002; }
121  }
122  lambda = paramK[idx][3]*resA + paramK[idx][4];
123  mu = paramK[idx][5]*amu1;
124  nu = amu1* (paramK[idx][7] + paramK[idx][8]*ec + paramK[idx][9]*ecsq);
125  }
126  /*
127  G4cout << "## idx= " << idx << " K= " << K << " elab= " << elab << " ec= " << ec
128  << " lambda= " << lambda << " mu= " << mu << " nu= " << nu << G4endl;
129  */
130  // threashold cross section
131  if(elab < ec) {
132  G4double p = paramK[idx][0];
133  if(0 < Z) { p += paramK[idx][1]/ec + paramK[idx][2]/ecsq; }
134  G4double a = -2*p*ec + lambda - nu/ecsq;
135  G4double b = p*ecsq + mu + 2*nu/ec;
136  G4double ecut;
137  G4double det = a*a - 4*p*b;
138  if (det > 0.0) { ecut = (std::sqrt(det) - a)/(2*p); }
139  else { ecut = -a/(2*p); }
140 
141  //G4cout << " elab= " << elab << " ecut= " << ecut << " sig= " << sig
142  // << " sig1= " << (p*elab*elab + a*elab + b)*signor << G4endl;
143  // If ecut>0, sig=0 at elab=ecut
144  if(0 == idx) {
145  sig = (lambda*ec + mu + nu/ec)*signor*std::sqrt(elab/ec);
146  } else if(elab >= ecut) {
147  sig = (p*elab*elab + a*elab + b)*signor;
148 
149  // extra proton correction
150  if(1 == idx) {
151  // c and w are for global correction factor for
152  // they are scaled down for light targets where ec is low.
153  G4double cc = std::min(3.15, ec*0.5);
154  G4double signor2 = (ec - elab - cc) *3.15/ (0.7*cc);
155  sig /= (1. + G4Exp(signor2));
156  }
157  }
158  //G4cout << " ecut= " << ecut << " a= " << a << " b= " << b
159  // << " signor= " << signor << " sig= " << sig << G4endl;
160 
161  // high energy cross section
162  } else {
163  // etest is the energy above which the rxn cross section is
164  // compared with the geometrical limit and the max taken.
165 
166  // neutron parameters
167  G4double etest = 32.;
168  G4double xnulam = 1.0;
169 
170  // parameters for charged
171  static const G4double flow = 1.e-18;
172  static const G4double spill= 1.e+18;
173  if(0 < Z) {
174  etest = 0.0;
175  xnulam = nu / lambda;
176  xnulam = std::min(xnulam, spill);
177  if (xnulam >= flow) {
178  if(1 == idx) { etest = std::sqrt(xnulam) + 7.; }
179  else { etest = 1.2 *std::sqrt(xnulam); }
180  }
181  }
182  // ** For xnulam.gt.0, sig reaches a maximum at sqrt(xnulam).
183  sig = (lambda*elab + mu + nu/elab)*signor;
184  if (xnulam >= flow && elab >= etest) {
185  G4double geom = std::sqrt(A*K);
186  geom = 1.23*resA13 + paramK[idx][10] + 4.573/geom;
187  geom = 31.416 * geom * geom;
188  sig = std::max(sig, geom);
189  }
190  }
191  sig = std::max(sig, 0.0);
192  //G4cout << " ---- sig= " << sig << G4endl;
193  return sig;
194  }
195 };
196 
197 #endif
static G4Pow * GetInstance()
Definition: G4Pow.cc:55
std::vector< ExP01TrackerHit * > a
Definition: ExP01Classes.hh:33
const char * p
Definition: xmltok.h:285
static G4double ComputePowerParameter(G4int resA, G4int idx)
int G4int
Definition: G4Types.hh:78
tuple b
Definition: test.py:12
double A(double temperature)
static G4double ComputeCrossSection(G4double K, G4double cb, G4double resA13, G4double amu1, G4int idx, G4int Z, G4int A, G4int resA)
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition: G4Exp.hh:183
T max(const T t1, const T t2)
brief Return the largest of the two arguments
T min(const T t1, const T t2)
brief Return the smallest of the two arguments
G4double powZ(G4int Z, G4double y) const
Definition: G4Pow.hh:254
double G4double
Definition: G4Types.hh:76
static const G4double paramK[6][11]