source: trunk/source/processes/electromagnetic/lowenergy/src/G4FinalStateElasticChampion.cc@ 992

Last change on this file since 992 was 991, checked in by garnier, 17 years ago

update
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1//
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20// * By using, copying, modifying or distributing the software (or *
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24// ********************************************************************
25//
26// $Id: G4FinalStateElasticChampion.cc,v 1.7 2008/12/10 18:25:28 sincerti Exp $
27// GEANT4 tag $Name: geant4-09-02 $
28// -------------------------------------------------------------------
29
30
31#include "G4FinalStateElasticChampion.hh"
32
33//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
34
35G4FinalStateElasticChampion::G4FinalStateElasticChampion()
36{
37 G4ParticleDefinition* electronDef = G4Electron::ElectronDefinition();
38
39 lowEnergyLimit = 8.23* eV; // SI : i/o of 7. * eV;
40 highEnergyLimit = 10. * keV;
41
42 G4double scaleFactor = 1e-16*cm*cm;
43
44 char *path = getenv("G4LEDATA");
45
46 if (!path)
47 G4Exception("G4FinalStateElasticChampion: constructor: G4LEDATA environment variable not set");
48
49 if (electronDef != 0)
50 {
51 std::ostringstream eFullFileName;
52 eFullFileName << path << "/dna/sigmadiff_elastic_e_champion.dat";
53 std::ifstream eDiffCrossSection(eFullFileName.str().c_str());
54
55 if (!eDiffCrossSection) G4Exception("G4FinalStateElasticChampion: constructor: error opening electron DATA FILE");
56
57 eTdummyVec.push_back(0.);
58
59 while(!eDiffCrossSection.eof())
60 {
61 double tDummy;
62 double eDummy;
63 eDiffCrossSection>>tDummy>>eDummy;
64
65 // SI : mandatory eVecm initialization
66 if (tDummy != eTdummyVec.back())
67 {
68 eTdummyVec.push_back(tDummy);
69 eVecm[tDummy].push_back(0.);
70 }
71
72 eDiffCrossSection>>eDiffCrossSectionData[0][tDummy][eDummy];
73
74 // SI : only if not end of file reached !
75 if (!eDiffCrossSection.eof()) eDiffCrossSectionData[0][tDummy][eDummy]*=scaleFactor;
76
77 if (eDummy != eVecm[tDummy].back()) eVecm[tDummy].push_back(eDummy);
78
79 }
80
81 }
82 else
83 {
84 G4Exception("G4FinalStateElastiChampion : constructor: electron is not defined");
85 }
86}
87
88//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
89
90G4FinalStateElasticChampion::~G4FinalStateElasticChampion()
91{
92 eVecm.clear();
93}
94
95//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
96
97const G4FinalStateProduct& G4FinalStateElasticChampion::GenerateFinalState(const G4Track& track, const G4Step& )
98{
99 product.Clear();
100
101 G4double k = track.GetDynamicParticle()->GetKineticEnergy();
102
103 if (k>= lowEnergyLimit && k < highEnergyLimit)
104 {
105 G4double cosTheta = RandomizeCosTheta(k);
106
107 G4double phi = 2. * pi * G4UniformRand();
108
109 G4ThreeVector zVers = track.GetDynamicParticle()->GetMomentumDirection();
110 G4ThreeVector xVers = zVers.orthogonal();
111 G4ThreeVector yVers = zVers.cross(xVers);
112
113 G4double xDir = std::sqrt(1. - cosTheta*cosTheta);
114 G4double yDir = xDir;
115 xDir *= std::cos(phi);
116 yDir *= std::sin(phi);
117
118 G4ThreeVector zPrimeVers((xDir*xVers + yDir*yVers + cosTheta*zVers));
119
120 product.ModifyPrimaryParticle(zPrimeVers,k);
121 }
122
123 if (k<lowEnergyLimit)
124 {
125 product.KillPrimaryParticle();
126 }
127
128 return product;
129}
130
131//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
132
133G4double G4FinalStateElasticChampion::DifferentialCrossSection
134 (G4ParticleDefinition * particleDefinition, G4double k, G4double theta)
135{
136 G4double sigma = 0.;
137 G4double valueT1 = 0;
138 G4double valueT2 = 0;
139 G4double valueE21 = 0;
140 G4double valueE22 = 0;
141 G4double valueE12 = 0;
142 G4double valueE11 = 0;
143 G4double xs11 = 0;
144 G4double xs12 = 0;
145 G4double xs21 = 0;
146 G4double xs22 = 0;
147
148 //SI : ensure the correct computation of cross section at the 180*deg limit
149 if (theta==180.) theta=theta-1e-9;
150
151 if (particleDefinition == G4Electron::ElectronDefinition())
152 {
153 std::vector<double>::iterator t2 = std::upper_bound(eTdummyVec.begin(),eTdummyVec.end(), k);
154 std::vector<double>::iterator t1 = t2-1;
155
156 std::vector<double>::iterator e12 = std::upper_bound(eVecm[(*t1)].begin(),eVecm[(*t1)].end(), theta);
157 std::vector<double>::iterator e11 = e12-1;
158
159 std::vector<double>::iterator e22 = std::upper_bound(eVecm[(*t2)].begin(),eVecm[(*t2)].end(), theta);
160 std::vector<double>::iterator e21 = e22-1;
161
162 valueT1 =*t1;
163 valueT2 =*t2;
164 valueE21 =*e21;
165 valueE22 =*e22;
166 valueE12 =*e12;
167 valueE11 =*e11;
168
169 xs11 = eDiffCrossSectionData[0][valueT1][valueE11];
170 xs12 = eDiffCrossSectionData[0][valueT1][valueE12];
171 xs21 = eDiffCrossSectionData[0][valueT2][valueE21];
172 xs22 = eDiffCrossSectionData[0][valueT2][valueE22];
173 }
174
175 G4double xsProduct = xs11 * xs12 * xs21 * xs22;
176
177 if (xs11==0 || xs12==0 ||xs21==0 ||xs22==0) return (0.);
178
179 if (xsProduct != 0.)
180 {
181 sigma = QuadInterpolator( valueE11, valueE12,
182 valueE21, valueE22,
183 xs11, xs12,
184 xs21, xs22,
185 valueT1, valueT2,
186 k, theta );
187 }
188
189 return sigma;
190}
191
192//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
193
194G4double G4FinalStateElasticChampion::LinLogInterpolate(G4double e1,
195 G4double e2,
196 G4double e,
197 G4double xs1,
198 G4double xs2)
199{
200 G4double d1 = std::log(xs1);
201 G4double d2 = std::log(xs2);
202 G4double value = std::exp(d1 + (d2 - d1)*(e - e1)/ (e2 - e1));
203 return value;
204}
205
206//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
207
208G4double G4FinalStateElasticChampion::LogLogInterpolate(G4double e1,
209 G4double e2,
210 G4double e,
211 G4double xs1,
212 G4double xs2)
213{
214 G4double a = (std::log10(xs2)-std::log10(xs1)) / (std::log10(e2)-std::log10(e1));
215 G4double b = std::log10(xs2) - a*std::log10(e2);
216 G4double sigma = a*std::log10(e) + b;
217 G4double value = (std::pow(10.,sigma));
218 return value;
219}
220
221//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
222
223G4double G4FinalStateElasticChampion::QuadInterpolator(G4double e11, G4double e12,
224 G4double e21, G4double e22,
225 G4double xs11, G4double xs12,
226 G4double xs21, G4double xs22,
227 G4double t1, G4double t2,
228 G4double t, G4double e)
229{
230// Log-Log
231/*
232 G4double interpolatedvalue1 = LogLogInterpolate(e11, e12, e, xs11, xs12);
233 G4double interpolatedvalue2 = LogLogInterpolate(e21, e22, e, xs21, xs22);
234 G4double value = LogLogInterpolate(t1, t2, t, interpolatedvalue1, interpolatedvalue2);
235*/
236
237// Lin-Log
238 G4double interpolatedvalue1 = LinLogInterpolate(e11, e12, e, xs11, xs12);
239 G4double interpolatedvalue2 = LinLogInterpolate(e21, e22, e, xs21, xs22);
240 G4double value = LinLogInterpolate(t1, t2, t, interpolatedvalue1, interpolatedvalue2);
241 return value;
242}
243
244//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
245
246G4double G4FinalStateElasticChampion::RandomizeCosTheta(G4double k)
247{
248
249 G4double cosTheta = -1;
250 G4double cumul = 0;
251 G4double value = 0;
252
253 // Number of integration steps in the 0-180 deg range
254 G4int iMax=180;
255
256 G4double random = G4UniformRand();
257
258 // Cumulate differential cross section
259 for (G4int i=0; i<iMax; i++)
260 {
261 cumul = cumul + DifferentialCrossSection(G4Electron::ElectronDefinition(),k/eV,G4double(i)*180./(iMax-1));
262 }
263
264 // Select theta angle
265 for (G4int i=0; i<iMax; i++)
266 {
267 value = value + DifferentialCrossSection(G4Electron::ElectronDefinition(),k/eV,G4double(i)*180./(iMax-1)) / cumul;
268 if (random < value)
269 {
270 cosTheta=std::cos( deg*G4double(i)*180./(iMax-1) );
271 break;
272 }
273 }
274
275 return cosTheta;
276}
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