Geant4  10.01
G4ionEffectiveCharge.cc
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26 // $Id: G4ionEffectiveCharge.cc 79394 2014-02-27 08:51:38Z gcosmo $
27 //
28 // -------------------------------------------------------------------
29 //
30 // GEANT4 Class file
31 //
32 //
33 // File name: G4ionEffectiveCharge
34 //
35 // Author: Vladimir Ivanchenko
36 //
37 // Creation date: 07.05.2002
38 //
39 // Modifications:
40 // 12.09.2004 Set low energy limit to 1 keV (V.Ivanchenko)
41 // 25.01.2005 Add protection - min Charge 0.1 eplus (V.Ivanchenko)
42 // 28.04.2006 Set upper energy limit to 50 MeV (V.Ivanchenko)
43 // 23.05.2006 Set upper energy limit to Z*10 MeV (V.Ivanchenko)
44 // 15.08.2006 Add protection for not defined material (V.Ivanchenko)
45 // 27-09-2007 Use Fermi energy from material, optimazed formulas (V.Ivanchenko)
46 //
47 
48 // -------------------------------------------------------------------
49 //
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52 
53 #include "G4ionEffectiveCharge.hh"
54 #include "G4PhysicalConstants.hh"
55 #include "G4SystemOfUnits.hh"
56 #include "G4UnitsTable.hh"
57 #include "G4Material.hh"
58 #include "G4NistManager.hh"
59 #include "G4Log.hh"
60 #include "G4Exp.hh"
61 #include "G4Pow.hh"
62 
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64 
66 
68 {
69  chargeCorrection = 1.0;
70  energyHighLimit = 20.0*MeV;
71  energyLowLimit = 1.0*keV;
72  energyBohr = 25.*keV;
73  massFactor = amu_c2/(proton_mass_c2*keV);
74  minCharge = 1.0;
75  lastPart = 0;
76  lastMat = 0;
77  lastKinEnergy = 0.0;
78  effCharge = eplus;
80 }
81 
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83 
85 {}
86 
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88 
90  const G4Material* material,
91  G4double kineticEnergy)
92 {
93  if(p == lastPart && material == lastMat && kineticEnergy == lastKinEnergy)
94  return effCharge;
95 
96  lastPart = p;
97  lastMat = material;
98  lastKinEnergy = kineticEnergy;
99 
100  G4double mass = p->GetPDGMass();
101  G4double charge = p->GetPDGCharge();
102  G4double Zi = charge*inveplus;
103 
104  chargeCorrection = 1.0;
105  effCharge = charge;
106 
107  // The aproximation of ion effective charge from:
108  // J.F.Ziegler, J.P. Biersack, U. Littmark
109  // The Stopping and Range of Ions in Matter,
110  // Vol.1, Pergamon Press, 1985
111  // Fast ions or hadrons
112  G4double reducedEnergy = kineticEnergy * proton_mass_c2/mass ;
113 
114  //G4cout << "e= " << reducedEnergy << " Zi= " << Zi << " "
115  //<< material->GetName() << G4endl;
116 
117  if(Zi < 1.5 || !material || reducedEnergy > Zi*energyHighLimit ) {
118  return charge;
119  }
120  G4double z = material->GetIonisation()->GetZeffective();
121  reducedEnergy = std::max(reducedEnergy,energyLowLimit);
122 
123  // Helium ion case
124  if( Zi < 2.5 ) {
125 
126  static const G4double c[6] =
127  {0.2865,0.1266,-0.001429,0.02402,-0.01135,0.001475};
128 
129  G4double Q = std::max(0.0,G4Log(reducedEnergy*massFactor));
130  G4double x = c[0];
131  G4double y = 1.0;
132  for (G4int i=1; i<6; ++i) {
133  y *= Q;
134  x += y * c[i] ;
135  }
136  G4double ex;
137  if(x < 0.2) { ex = x * (1 - 0.5*x); }
138  else { ex = 1. - G4Exp(-x); }
139 
140  G4double tq = 7.6 - Q;
141  G4double tq2= tq*tq;
142  G4double tt = ( 0.007 + 0.00005 * z );
143  if(tq2 < 0.2) { tt *= (1.0 - tq2 + 0.5*tq2*tq2); }
144  else { tt *= G4Exp(-tq2); }
145 
146  effCharge = charge*(1.0 + tt) * std::sqrt(ex);
147 
148  // Heavy ion case
149  } else {
150 
151  G4double y;
152  G4double zi13 = g4pow->A13(Zi);
153  G4double zi23 = zi13*zi13;
154 
155  // v1 is ion velocity in vF unit
156  G4double eF = material->GetIonisation()->GetFermiEnergy();
157  G4double v1sq = reducedEnergy/eF;
158  G4double vFsq = eF/energyBohr;
159  G4double vF = std::sqrt(eF/energyBohr);
160 
161  // Faster than Fermi velocity
162  if ( v1sq > 1.0 ) {
163  y = vF * std::sqrt(v1sq) * ( 1.0 + 0.2/v1sq ) / zi23 ;
164 
165  // Slower than Fermi velocity
166  } else {
167  y = 0.692308 * vF * (1.0 + 0.666666*v1sq + v1sq*v1sq/15.0) / zi23 ;
168  }
169 
170  G4double q;
171  G4double y3 = std::pow(y, 0.3) ;
172  // G4cout<<"y= "<<y<<" y3= "<<y3<<" v1= "<<v1<<" vF= "<<vF<<G4endl;
173  q = 1.0 - G4Exp( 0.803*y3 - 1.3167*y3*y3 - 0.38157*y - 0.008983*y*y);
174  q = std::max(q, minCharge/Zi);
175 
176  effCharge = q*charge;
177 
178  G4double tq = 7.6 - G4Log(reducedEnergy/keV);
179  G4double tq2= tq*tq;
180  G4double sq = 1.0 + ( 0.18 + 0.0015 * z )*G4Exp(-tq2)/ (Zi*Zi);
181 
182  // G4cout << "sq= " << sq << G4endl;
183 
184  // Screen length according to
185  // J.F.Ziegler and J.M.Manoyan, The stopping of ions in compaunds,
186  // Nucl. Inst. & Meth. in Phys. Res. B35 (1988) 215-228.
187 
188  G4double lambda = 10.0 * vF *g4pow->A23(1.0 - q)/ (zi13 * (6.0 + q));
189 
190  G4double lambda2 = lambda*lambda;
191 
192  G4double xx = (0.5/q - 0.5)*G4Log(1.0 + lambda2)/vFsq;
193 
194  chargeCorrection = sq * (1.0 + xx);
195 
196  }
197  // G4cout << "G4ionEffectiveCharge: charge= " << charge << " q= " << q
198  // << " chargeCor= " << chargeCorrection
199  // << " e(MeV)= " << kineticEnergy/MeV << G4endl;
200  return effCharge;
201 }
202 
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204 
205 
static G4Pow * GetInstance()
Definition: G4Pow.cc:55
const G4Material * lastMat
G4IonisParamMat * GetIonisation() const
Definition: G4Material.hh:224
static const double MeV
Definition: G4SIunits.hh:193
G4double z
Definition: TRTMaterials.hh:39
int G4int
Definition: G4Types.hh:78
G4double GetZeffective() const
G4double GetFermiEnergy() const
G4double A23(G4double A) const
Definition: G4Pow.hh:157
const G4ParticleDefinition * lastPart
G4double G4Log(G4double x)
Definition: G4Log.hh:230
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition: G4Exp.hh:183
G4double EffectiveCharge(const G4ParticleDefinition *p, const G4Material *material, G4double kineticEnergy)
G4double GetPDGMass() const
G4double A13(G4double A) const
Definition: G4Pow.hh:132
T max(const T t1, const T t2)
brief Return the largest of the two arguments
static const double keV
Definition: G4SIunits.hh:195
double G4double
Definition: G4Types.hh:76
static const double eplus
Definition: G4SIunits.hh:178
G4double GetPDGCharge() const
static const G4double inveplus