source: trunk/source/processes/electromagnetic/lowenergy/src/G4CrossSectionExcitationMillerGreenPartial.cc @ 1347

Last change on this file since 1347 was 1347, checked in by garnier, 13 years ago

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26// $Id: G4CrossSectionExcitationMillerGreenPartial.cc,v 1.4 2009/06/10 13:32:36 mantero Exp $
27// GEANT4 tag $Name: geant4-09-04-ref-00 $
28
29#include "G4CrossSectionExcitationMillerGreenPartial.hh"
30
31//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
32
33G4CrossSectionExcitationMillerGreenPartial::G4CrossSectionExcitationMillerGreenPartial()
34{
35  nLevels = waterExcitation.NumberOfLevels();
36 
37  //PROTON
38  kineticEnergyCorrection[0] = 1.;
39  slaterEffectiveCharge[0][0] = 0.;
40  slaterEffectiveCharge[1][0] = 0.;
41  slaterEffectiveCharge[2][0] = 0.;
42  sCoefficient[0][0] = 0.;
43  sCoefficient[1][0] = 0.;
44  sCoefficient[2][0] = 0.;
45
46  //ALPHA++
47  kineticEnergyCorrection[1] = 0.9382723/3.727417;
48  slaterEffectiveCharge[0][1]=0.;
49  slaterEffectiveCharge[1][1]=0.;
50  slaterEffectiveCharge[2][1]=0.;
51  sCoefficient[0][1]=0.;
52  sCoefficient[1][1]=0.;
53  sCoefficient[2][1]=0.;
54
55  // ALPHA+
56  kineticEnergyCorrection[2] = 0.9382723/3.727417;
57  slaterEffectiveCharge[0][2]=2.0;
58  slaterEffectiveCharge[1][2]=1.15;
59  slaterEffectiveCharge[2][2]=1.15;
60  sCoefficient[0][2]=0.7;
61  sCoefficient[1][2]=0.15;
62  sCoefficient[2][2]=0.15;
63
64  // HELIUM
65  kineticEnergyCorrection[3] = 0.9382723/3.727417;
66  slaterEffectiveCharge[0][3]=1.7;
67  slaterEffectiveCharge[1][3]=1.15;
68  slaterEffectiveCharge[2][3]=1.15;
69  sCoefficient[0][3]=0.5;
70  sCoefficient[1][3]=0.25;
71  sCoefficient[2][3]=0.25; 
72 
73}
74
75//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
76
77G4CrossSectionExcitationMillerGreenPartial::~G4CrossSectionExcitationMillerGreenPartial()
78{}
79 
80//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
81
82G4double G4CrossSectionExcitationMillerGreenPartial::CrossSection(G4double k, G4int excitationLevel, 
83                                                                  const G4ParticleDefinition* particleDefinition)
84{
85  //                               ( ( z * aj ) ^ omegaj ) * ( t - ej ) ^ nu
86  // sigma(t) = zEff^2 * sigma0 * --------------------------------------------
87  //                               jj ^ ( omegaj + nu ) + t ^ ( omegaj + nu )
88  //
89  // where t is the kinetic energy corrected by Helium mass over proton mass for Helium ions
90  //
91  // zEff is:
92  //  1 for protons
93  //  2 for alpha++
94  //  and  2 - c1 S_1s - c2 S_2s - c3 S_2p for alpha+ and He
95  //
96  // Dingfelder et al., RPC 59, 255-275, 2000 from Miller and Green (1973)
97  // Formula (34) and Table 2
98 
99  const G4double sigma0(1.E+8 * barn);
100  const G4double nu(1.);
101  const G4double aj[]={876.*eV, 2084.* eV, 1373.*eV, 692.*eV, 900.*eV};
102  const G4double jj[]={19820.*eV, 23490.*eV, 27770.*eV, 30830.*eV, 33080.*eV};
103  const G4double omegaj[]={0.85, 0.88, 0.88, 0.78, 0.78};
104 
105  G4int particleTypeIndex = 0;
106  G4DNAGenericIonsManager* instance;
107  instance = G4DNAGenericIonsManager::Instance();
108
109  if (particleDefinition == G4Proton::ProtonDefinition()) particleTypeIndex=0;
110  if (particleDefinition == instance->GetIon("alpha++")) particleTypeIndex=1;
111  if (particleDefinition == instance->GetIon("alpha+")) particleTypeIndex=2;
112  if (particleDefinition == instance->GetIon("helium")) particleTypeIndex=3;
113 
114  G4double tCorrected;
115  tCorrected = k * kineticEnergyCorrection[particleTypeIndex];
116
117  // SI - added protection
118  if (tCorrected < waterExcitation.ExcitationEnergy(excitationLevel)) return 0;
119  //
120 
121  G4int z = 10;
122
123  G4double numerator;
124  numerator = std::pow(z * aj[excitationLevel], omegaj[excitationLevel]) * 
125    std::pow(tCorrected - waterExcitation.ExcitationEnergy(excitationLevel), nu);
126
127  G4double power;
128  power = omegaj[excitationLevel] + nu;
129
130  G4double denominator;
131  denominator = std::pow(jj[excitationLevel], power) + std::pow(tCorrected, power);
132
133  G4double zEff = particleDefinition->GetPDGCharge() / eplus + particleDefinition->GetLeptonNumber();
134
135  zEff -= ( sCoefficient[0][particleTypeIndex] * S_1s(k, waterExcitation.ExcitationEnergy(excitationLevel), slaterEffectiveCharge[0][particleTypeIndex], 1.) +
136            sCoefficient[1][particleTypeIndex] * S_2s(k, waterExcitation.ExcitationEnergy(excitationLevel), slaterEffectiveCharge[1][particleTypeIndex], 2.) +
137            sCoefficient[2][particleTypeIndex] * S_2p(k, waterExcitation.ExcitationEnergy(excitationLevel), slaterEffectiveCharge[2][particleTypeIndex], 2.) );
138
139  G4double cross = sigma0 * zEff * zEff * numerator / denominator;
140
141  return cross;
142}
143
144//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
145
146G4int G4CrossSectionExcitationMillerGreenPartial::RandomSelect(G4double k, 
147                                                               const G4ParticleDefinition* particle)
148{
149  G4int i = nLevels;
150  G4double value = 0.;
151  std::deque<double> values;
152 
153  // ---- MGP ---- The following algorithm is wrong: it works if the cross section
154  // is a monotone increasing function.
155  // The algorithm should be corrected by building the cumulative function
156  // of the cross section and comparing a random number in the range 0-1 against
157  // the cumulative value at each bin
158
159  G4DNAGenericIonsManager *instance;
160  instance = G4DNAGenericIonsManager::Instance();
161
162  // ELECTRON CORRECTION
163 
164  if ( particle == instance->GetIon("alpha++")||
165       particle == G4Proton::ProtonDefinition())
166       
167  {  while (i > 0)
168     {
169        i--;
170        G4double partial = CrossSection(k,i,particle);
171        values.push_front(partial);
172        value += partial;
173     }
174
175     value *= G4UniformRand();
176   
177     i = nLevels;
178
179     while (i > 0)
180     {
181        i--;
182        if (values[i] > value) return i;
183        value -= values[i];
184     }
185  } 
186
187  // add ONE or TWO electron-water excitation for alpha+ and helium
188   
189  if ( particle == instance->GetIon("alpha+") 
190       ||
191       particle == instance->GetIon("helium")
192     ) 
193  {
194    while (i>0)
195    {
196          i--;
197         
198          G4CrossSectionExcitationEmfietzoglouPartial* excitationXS = 
199            new G4CrossSectionExcitationEmfietzoglouPartial();
200         
201          G4double sigmaExcitation=0;
202          if (k*0.511/3728 > 7.4*eV && k*0.511/3728 < 10*keV) sigmaExcitation = excitationXS->CrossSection(k*0.511/3728,i);
203 
204          G4double partial = CrossSection(k,i,particle);
205          if (particle == instance->GetIon("alpha+")) partial = CrossSection(k,i,particle) + sigmaExcitation;
206          if (particle == instance->GetIon("helium")) partial = CrossSection(k,i,particle) + 2*sigmaExcitation;
207          values.push_front(partial);
208          value += partial;
209          delete excitationXS;
210    }
211 
212    value*=G4UniformRand();
213 
214    i=5;
215    while (i>0)
216    {
217          i--;
218   
219          if (values[i]>value) return i;
220 
221          value-=values[i];
222    }
223  }   
224  //   
225
226  return 0;
227}
228
229//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
230
231G4double G4CrossSectionExcitationMillerGreenPartial::Sum(G4double k, const G4ParticleDefinition* particle)
232{
233  G4double totalCrossSection = 0.;
234
235  for (G4int i=0; i<nLevels; i++)
236  {
237    totalCrossSection += CrossSection(k,i,particle);
238  }
239  return totalCrossSection;
240}
241
242//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
243
244G4double G4CrossSectionExcitationMillerGreenPartial::S_1s(G4double t,
245                                                          G4double energyTransferred,
246                                                          G4double slaterEffectiveCharge,
247                                                          G4double shellNumber)
248{
249  // 1 - e^(-2r) * ( 1 + 2 r + 2 r^2)
250  // Dingfelder, in Chattanooga 2005 proceedings, formula (7)
251 
252  G4double r = R(t, energyTransferred, slaterEffectiveCharge, shellNumber);
253  G4double value = 1. - std::exp(-2 * r) * ( ( 2. * r + 2. ) * r + 1. );
254 
255  return value;
256}
257
258
259//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
260
261G4double G4CrossSectionExcitationMillerGreenPartial::S_2s(G4double t,
262                                                          G4double energyTransferred,
263                                                          G4double slaterEffectiveCharge,
264                                                          G4double shellNumber)
265{
266  // 1 - e^(-2 r) * ( 1 + 2 r + 2 r^2 + 2 r^4)
267  // Dingfelder, in Chattanooga 2005 proceedings, formula (8)
268
269  G4double r = R(t, energyTransferred, slaterEffectiveCharge, shellNumber);
270  G4double value =  1. - std::exp(-2 * r) * (((2. * r * r + 2.) * r + 2.) * r + 1.);
271
272  return value;
273 
274}
275
276//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
277
278G4double G4CrossSectionExcitationMillerGreenPartial::S_2p(G4double t,
279                                                          G4double energyTransferred,
280                                                          G4double slaterEffectiveCharge,
281                                                          G4double shellNumber)
282{
283  // 1 - e^(-2 r) * ( 1 + 2 r + 2 r^2 + 4/3 r^3 + 2/3 r^4)
284  // Dingfelder, in Chattanooga 2005 proceedings, formula (9)
285
286  G4double r = R(t, energyTransferred, slaterEffectiveCharge, shellNumber);
287  G4double value =  1. - std::exp(-2 * r) * (((( 2./3. * r + 4./3.) * r + 2.) * r + 2.) * r  + 1.);
288
289  return value;
290}
291
292//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
293
294G4double G4CrossSectionExcitationMillerGreenPartial::R(G4double t,
295                                                       G4double energyTransferred,
296                                                       G4double slaterEffectiveCharge,
297                                                       G4double shellNumber) 
298{
299  // tElectron = m_electron / m_alpha * t
300  // Hardcoded in Riccardo's implementation; to be corrected
301  // Dingfelder, in Chattanooga 2005 proceedings, p 4
302
303  G4double tElectron = 0.511/3728. * t;
304  G4double value = 2. * tElectron * slaterEffectiveCharge / (energyTransferred * shellNumber);
305 
306  return value;
307}
308
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