| Geant4 Cross Reference |
1 //
2 // ********************************************************************
3 // * License and Disclaimer *
4 // * *
5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. *
10 // * *
11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitation of liability. *
17 // * *
18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Software license. *
24 // ********************************************************************
25 //
26 // 19.09.21 V. Grichine, first version
27 //
28
29 #include "G4GaussXTRadiator.hh"
30
31 #include "G4PhysicalConstants.hh"
32
33 ////////////////////////////////////////////////////////////////////////////
34 // Constructor, destructor
35
36 G4GaussXTRadiator::G4GaussXTRadiator(
37 G4LogicalVolume* anEnvelope, G4double alphaPlate, G4double alphaGas, G4Material* foilMat, G4Material* gasMat,
38 G4double a, G4double b, G4int n, const G4String& processName)
39 : G4VXTRenergyLoss(anEnvelope, foilMat, gasMat, a, b, n, processName)
40 {
41 if(verboseLevel > 0)
42 G4cout << "Gauss X-ray TR radiator EM process is called"
43 << G4endl;
44
45 fAlphaPlate = alphaPlate;
46 fAlphaGas = alphaGas; // 1000; //
47 }
48
49 ///////////////////////////////////////////////////////////////////////////
50 G4GaussXTRadiator::~G4GaussXTRadiator() = default;
51
52 ///////////////////////////////////////////////////////////////////////////
53 void G4GaussXTRadiator::ProcessDescription(std::ostream& out) const
54 {
55 out << "Simulation of forward X-ray transition radiation generated by\n"
56 "relativistic charged particles crossing the interface between\n"
57 "two materials.\n";
58 }
59
60 ///////////////////////////////////////////////////////////////////////////
61 //
62 // The Fabian-Strujinsky (FS) algorithm for integration over XTR angle,
63 // resolution is about 0.1-0.5 mrad
64
65 G4double G4GaussXTRadiator::SpectralXTRdEdx(G4double energy)
66 {
67 G4double result, sum = 0., tmp, cof1, cof2, cofMin, cofPHC, theta2, theta2k;
68 G4int k, kMax, kMin;
69
70 cofPHC = 4. * pi * hbarc;
71 tmp = (fSigma1 - fSigma2) / cofPHC / energy;
72 cof1 = fPlateThick * tmp;
73 cof2 = fGasThick * tmp;
74
75 cofMin = energy * (fPlateThick + fGasThick) / fGamma / fGamma;
76 cofMin += (fPlateThick * fSigma1 + fGasThick * fSigma2) / energy;
77 cofMin /= cofPHC;
78
79 theta2 = cofPHC / (energy * (fPlateThick + fGasThick));
80
81 kMin = G4int(cofMin);
82 if(cofMin > kMin)
83 kMin++;
84
85 kMax = kMin + fKrange;
86
87 if(verboseLevel > 2)
88 {
89 G4cout << cof1 << " " << cof2 << " " << cofMin << G4endl;
90 G4cout << "kMin = " << kMin << "; kMax = " << kMax << G4endl;
91 }
92 for(k = kMin; k <= kMax; ++k)
93 {
94 tmp = pi * fPlateThick * (k + cof2) / (fPlateThick + fGasThick);
95 result = (k - cof1) * (k - cof1) * (k + cof2) * (k + cof2);
96 if(k == kMin && kMin == G4int(cofMin))
97 {
98 sum +=
99 0.5 * std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result;
100 }
101 else
102 {
103 sum += std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result;
104 }
105 theta2k = std::sqrt(theta2 * std::abs(k - cofMin));
106
107 if(verboseLevel > 2)
108 {
109 G4cout << k << " " << theta2k << " "
110 << std::sin(tmp) * std::sin(tmp) * std::abs(k - cofMin) / result
111 << " " << sum << G4endl;
112 }
113 }
114 result = 4. * (cof1 + cof2) * (cof1 + cof2) * sum / energy;
115 result *= fPlateNumber;
116
117 return result;
118 }
119
120 ///////////////////////////////////////////////////////////////////////////
121 //
122 // Approximation for radiator interference factor for the case of
123 // Gauss-distributed regular radiator. The plate and gas gap thicknesses are Gauss distributed with RMS
124 // sa and sb for plate and gas, respectively.
125 // The mean values of the plate and gas gap thicknesses
126 // are supposed to be about XTR formation zones.
127
128
129 G4double G4GaussXTRadiator::GetStackFactor(G4double energy,
130 G4double gamma,
131 G4double varAngle)
132 {
133 G4double result(0.);
134 G4double sa = fPlateThick/fAlphaPlate;
135 G4double sb = fGasThick/fAlphaGas;
136 G4double nn = G4double(fPlateNumber);
137
138 G4complex med( 0., 1.);
139 G4complex Z1 = GetPlateComplexFZ( energy, gamma, varAngle);
140 G4complex order1 = -0.5*med*fPlateThick/Z1 - 0.125*sa*sa/Z1/Z1;
141
142 G4complex Z2 = GetGasComplexFZ( energy, gamma, varAngle);
143 G4complex order2 = -0.5*med*fGasThick/Z2 - 0.125*sb*sb/Z2/Z2;
144
145 G4complex ordernn = ( order1 + order2 )*nn;
146
147 G4complex Ha = std::exp( order1 );
148 G4complex Hb = std::exp( order2 );
149 G4complex H = Ha * Hb;
150 G4complex Hn = std::exp( ordernn );
151
152 G4complex F1 = ( 1.0 - Ha ) * ( 1.0 - Hb ) * nn / ( 1. - H );
153
154 G4complex F2 = ( 1.0 - Ha ) * ( 1.0 - Ha ) * Hb * ( 1. - Hn ) / ( 1. - H ) / ( 1. - H );
155
156 G4complex R = (F1 + F2) * OneInterfaceXTRdEdx(energy, gamma, varAngle);
157
158 result = 2.0 * std::real(R);
159
160 return result;
161 }
162