source: trunk/source/processes/electromagnetic/lowenergy/src/G4eBremsstrahlungSpectrum.cc@ 1201

Last change on this file since 1201 was 1196, checked in by garnier, 16 years ago

update CVS release candidate geant4.9.3.01
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[819]1//
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25//
[1192]26// $Id: G4eBremsstrahlungSpectrum.cc,v 1.16 2009/06/10 13:32:36 mantero Exp $
[1196]27// GEANT4 tag $Name: geant4-09-03-cand-01 $
[819]28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class file
32//
33//
34// File name: G4eBremsstrahlungSpectrum
35//
36// Author: V.Ivanchenko (Vladimir.Ivanchenko@cern.ch)
37//
38// Creation date: 29 September 2001
39//
40// Modifications:
41// 10.10.01 MGP Revision to improve code quality and consistency with design
42// 15.11.01 VI Update spectrum model Bethe-Haitler spectrum at high energy
43// 30.05.02 VI Update interpolation between 2 last energy points in the
44// parametrisation
45// 21.02.03 V.Ivanchenko Energy bins are defined in the constructor
46// 28.02.03 V.Ivanchenko Filename is defined in the constructor
47//
48// -------------------------------------------------------------------
49
50#include "G4eBremsstrahlungSpectrum.hh"
51#include "G4BremsstrahlungParameters.hh"
52#include "Randomize.hh"
53
54
55G4eBremsstrahlungSpectrum::G4eBremsstrahlungSpectrum(const G4DataVector& bins,
56 const G4String& name):G4VEnergySpectrum(),
57 lowestE(0.1*eV),
58 xp(bins)
59{
60 length = xp.size();
61 theBRparam = new G4BremsstrahlungParameters(name,length+1);
62
63 verbose = 0;
64}
65
66
67G4eBremsstrahlungSpectrum::~G4eBremsstrahlungSpectrum()
68{
69 delete theBRparam;
70}
71
72
73G4double G4eBremsstrahlungSpectrum::Probability(G4int Z,
74 G4double tmin,
75 G4double tmax,
76 G4double e,
77 G4int,
78 const G4ParticleDefinition*) const
79{
80 G4double tm = std::min(tmax, e);
81 G4double t0 = std::max(tmin, lowestE);
82 if(t0 >= tm) return 0.0;
83
84 t0 /= e;
85 tm /= e;
86
87 G4double z0 = lowestE/e;
88 G4DataVector p;
89
90 // Access parameters
91 for (size_t i=0; i<=length; i++) {
92 p.push_back(theBRparam->Parameter(i, Z, e));
93 }
94
95 G4double x = IntSpectrum(t0, tm, p);
96 G4double y = IntSpectrum(z0, 1.0, p);
97
98
99 if(1 < verbose) {
100 G4cout << "tcut(MeV)= " << tmin/MeV
101 << "; tMax(MeV)= " << tmax/MeV
102 << "; t0= " << t0
103 << "; tm= " << tm
104 << "; xp[0]= " << xp[0]
105 << "; z= " << z0
106 << "; val= " << x
107 << "; nor= " << y
108 << G4endl;
109 }
110 p.clear();
111
112 if(y > 0.0) x /= y;
113 else x = 0.0;
114 // if(x < 0.0) x = 0.0;
115
116 return x;
117}
118
119
120G4double G4eBremsstrahlungSpectrum::AverageEnergy(G4int Z,
121 G4double tmin,
122 G4double tmax,
123 G4double e,
124 G4int,
125 const G4ParticleDefinition*) const
126{
127 G4double tm = std::min(tmax, e);
128 G4double t0 = std::max(tmin, lowestE);
129 if(t0 >= tm) return 0.0;
130
131 t0 /= e;
132 tm /= e;
133
134 G4double z0 = lowestE/e;
135
136 G4DataVector p;
137
138 // Access parameters
139 for (size_t i=0; i<=length; i++) {
140 p.push_back(theBRparam->Parameter(i, Z, e));
141 }
142
143 G4double x = AverageValue(t0, tm, p);
144 G4double y = IntSpectrum(z0, 1.0, p);
145
146 // Add integrant over lowest energies
147 G4double zmin = tmin/e;
148 if(zmin < t0) {
149 G4double c = std::sqrt(theBRparam->ParameterC(Z));
150 x += p[0]*(t0 - zmin - c*(std::atan(t0/c) - std::atan(zmin/c)));
151 }
152 x *= e;
153
154 if(1 < verbose) {
155 G4cout << "tcut(MeV)= " << tmin/MeV
156 << "; tMax(MeV)= " << tmax/MeV
157 << "; e(MeV)= " << e/MeV
158 << "; t0= " << t0
159 << "; tm= " << tm
160 << "; y= " << y
161 << "; x= " << x
162 << G4endl;
163 }
164 p.clear();
165
166 if(y > 0.0) x /= y;
167 else x = 0.0;
168 // if(x < 0.0) x = 0.0;
169
170 return x;
171}
172
173
174G4double G4eBremsstrahlungSpectrum::SampleEnergy(G4int Z,
175 G4double tmin,
176 G4double tmax,
177 G4double e,
178 G4int,
179 const G4ParticleDefinition*) const
180{
181 G4double tm = std::min(tmax, e);
182 G4double t0 = std::max(tmin, lowestE);
183 if(t0 >= tm) return 0.0;
184
185 t0 /= e;
186 tm /= e;
187
188 G4DataVector p;
189
190 for (size_t i=0; i<=length; i++) {
191 p.push_back(theBRparam->Parameter(i, Z, e));
192 }
193 G4double amaj = std::max(p[length], 1. - (p[1] - p[0])*xp[0]/(xp[1] - xp[0]) );
194
195 G4double amax = std::log(tm);
196 G4double amin = std::log(t0);
197 G4double tgam, q, fun;
198
199 do {
200 G4double x = amin + G4UniformRand()*(amax - amin);
201 tgam = std::exp(x);
202 fun = Function(tgam, p);
203
204 if(fun > amaj) {
205 G4cout << "WARNING in G4eBremsstrahlungSpectrum::SampleEnergy:"
206 << " Majoranta " << amaj
207 << " < " << fun
208 << G4endl;
209 }
210
211 q = amaj * G4UniformRand();
212 } while (q > fun);
213
214 tgam *= e;
215
216 p.clear();
217
218 return tgam;
219}
220
221G4double G4eBremsstrahlungSpectrum::IntSpectrum(G4double xMin,
222 G4double xMax,
223 const G4DataVector& p) const
224{
225 G4double x1 = std::min(xMin, xp[0]);
226 G4double x2 = std::min(xMax, xp[0]);
227 G4double sum = 0.0;
228
229 if(x1 < x2) {
230 G4double k = (p[1] - p[0])/(xp[1] - xp[0]);
231 sum += (1. - k*xp[0])*std::log(x2/x1) + k*(x2 - x1);
232 }
233
234 for (size_t i=0; i<length-1; i++) {
235 x1 = std::max(xMin, xp[i]);
236 x2 = std::min(xMax, xp[i+1]);
237 if(x1 < x2) {
238 G4double z1 = p[i];
239 G4double z2 = p[i+1];
240 sum += z2 - z1 + std::log(x2/x1)*(z1*x2 - z2*x1)/(x2 - x1);
241 }
242 }
243 if(sum < 0.0) sum = 0.0;
244 return sum;
245}
246
247G4double G4eBremsstrahlungSpectrum::AverageValue(G4double xMin,
248 G4double xMax,
249 const G4DataVector& p) const
250{
251 G4double x1 = std::min(xMin, xp[0]);
252 G4double x2 = std::min(xMax, xp[0]);
253 G4double z1 = x1;
254 G4double z2 = x2;
255 G4double sum = 0.0;
256
257 if(x1 < x2) {
258 G4double k = (p[1] - p[0])/(xp[1] - xp[0]);
259 sum += (z2 - z1)*(1. - k*xp[0]);
260 z1 *= x1;
261 z2 *= x2;
262 sum += 0.5*k*(z2 - z1);
263 }
264
265 for (size_t i=0; i<length-1; i++) {
266 x1 = std::max(xMin, xp[i]);
267 x2 = std::min(xMax, xp[i+1]);
268 if(x1 < x2) {
269 z1 = p[i];
270 z2 = p[i+1];
271 sum += 0.5*(z2 - z1)*(x2 + x1) + z1*x2 - z2*x1;
272 }
273 }
274 if(sum < 0.0) sum = 0.0;
275 return sum;
276}
277
278G4double G4eBremsstrahlungSpectrum::Function(G4double x,
279 const G4DataVector& p) const
280{
281 G4double f = 0.0;
282
283 if(x <= xp[0]) {
284 f = p[0] + (p[1] - p[0])*(x - xp[0])/(xp[1] - xp[0]);
285
286 } else {
287
288 for (size_t i=0; i<length-1; i++) {
289
290 if(x <= xp[i+1]) {
291 f = p[i] + (p[i+1] - p[i])*(x - xp[i])/(xp[i+1] - xp[i]);
292 break;
293 }
294 }
295 }
296 return f;
297}
298
299void G4eBremsstrahlungSpectrum::PrintData() const
300{ theBRparam->PrintData(); }
301
302G4double G4eBremsstrahlungSpectrum::Excitation(G4int , G4double ) const
303{
304 return 0.0;
305}
306
307G4double G4eBremsstrahlungSpectrum::MaxEnergyOfSecondaries(G4double kineticEnergy,
308 G4int, // Z,
309 const G4ParticleDefinition*) const
310{
311 return kineticEnergy;
312}
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