| 1 | //
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| 2 | // ********************************************************************
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| 3 | // * License and Disclaimer *
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| 4 | // * *
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of *
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and *
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| 7 | // * conditions of the Geant4 Software License, included in the file *
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These *
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| 9 | // * include a list of copyright holders. *
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| 10 | // * *
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| 11 | // * Neither the authors of this software system, nor their employing *
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| 12 | // * institutes,nor the agencies providing financial support for this *
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| 13 | // * work make any representation or warranty, express or implied, *
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| 14 | // * regarding this software system or assume any liability for its *
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| 15 | // * use. Please see the license in the file LICENSE and URL above *
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| 16 | // * for the full disclaimer and the limitation of liability. *
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| 17 | // * *
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| 18 | // * This code implementation is the result of the scientific and *
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| 19 | // * technical work of the GEANT4 collaboration. *
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| 20 | // * By using, copying, modifying or distributing the software (or *
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| 21 | // * any work based on the software) you agree to acknowledge its *
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| 22 | // * use in resulting scientific publications, and indicate your *
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| 23 | // * acceptance of all terms of the Geant4 Software license. *
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| 24 | // ********************************************************************
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| 25 | //
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| 26 | #include "G4AngularDistributionPP.hh"
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| 27 | #include "Randomize.hh"
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| 28 | #include "G4ios.hh"
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| 29 |
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| 30 | // Initialization of static data arrays:
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| 31 | #include "G4AngularDistributionPPData.hh"
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| 32 | #include "Randomize.hh"
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| 33 |
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| 34 |
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| 35 | G4double G4AngularDistributionPP::CosTheta(G4double s, G4double m1, G4double m2) const
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| 36 | {
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| 37 | G4int verboseLevel=1;
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| 38 |
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| 39 | G4double ek= ((s - sqr(m1) -sqr(m2) )/(2*m1) - m1 )/GeV ; // kinetic energy in GeV
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| 40 |
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| 41 | // Find energy bin
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| 42 |
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| 43 | G4int je1 = 0;
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| 44 | G4int je2 = NENERGY - 1;
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| 45 | do {
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| 46 | G4int midBin = (je1 + je2)/2;
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| 47 | if (ek < elab[midBin])
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| 48 | je2 = midBin;
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| 49 | else
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| 50 | je1 = midBin;
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| 51 | } while (je2 - je1 > 1);
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| 52 | // G4int j;
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| 53 | //std::abs(ek-elab[je1]) < std::abs(ek-elab[je2]) ? j = je1 : j = je2;
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| 54 | G4double delab = elab[je2] - elab[je1];
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| 55 |
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| 56 | // Sample the angle
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| 57 |
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| 58 | G4float sample = G4UniformRand();
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| 59 | G4int ke1 = 0;
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| 60 | G4int ke2 = NANGLE - 1;
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| 61 | G4double dsig = sig[je2][0] - sig[je1][0];
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| 62 | G4double rc = dsig/delab;
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| 63 | G4double b = sig[je1][0] - rc*elab[je1];
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| 64 | G4double sigint1 = rc*ek + b;
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| 65 | G4double sigint2 = 0.;
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| 66 |
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| 67 | if (verboseLevel > 1) G4cout << "sample=" << sample << G4endl
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| 68 | << ek << " " << ke1 << " " << ke2 << " "
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| 69 | << sigint1 << " " << sigint2 << G4endl;
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| 70 |
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| 71 | do {
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| 72 | G4int midBin = (ke1 + ke2)/2;
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| 73 | dsig = sig[je2][midBin] - sig[je1][midBin];
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| 74 | rc = dsig/delab;
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| 75 | b = sig[je1][midBin] - rc*elab[je1];
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| 76 | G4double sigint = rc*ek + b;
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| 77 | if (sample < sigint) {
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| 78 | ke2 = midBin;
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| 79 | sigint2 = sigint;
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| 80 | }
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| 81 | else {
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| 82 | ke1 = midBin;
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| 83 | sigint1 = sigint;
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| 84 | }
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| 85 | if (verboseLevel > 1)G4cout << ke1 << " " << ke2 << " "
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| 86 | << sigint1 << " " << sigint2 << G4endl;
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| 87 | } while (ke2 - ke1 > 1);
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| 88 |
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| 89 | // sigint1 and sigint2 should be recoverable from above loop
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| 90 |
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| 91 | // G4double dsig = sig[je2][ke1] - sig[je1][ke1];
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| 92 | // G4double rc = dsig/delab;
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| 93 | // G4double b = sig[je1][ke1] - rc*elab[je1];
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| 94 | // G4double sigint1 = rc*ek + b;
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| 95 |
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| 96 | // G4double dsig = sig[je2][ke2] - sig[je1][ke2];
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| 97 | // G4double rc = dsig/delab;
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| 98 | // G4double b = sig[je1][ke2] - rc*elab[je1];
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| 99 | // G4double sigint2 = rc*ek + b;
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| 100 |
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| 101 | dsig = sigint2 - sigint1;
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| 102 | rc = 1./dsig;
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| 103 | b = ke1 - rc*sigint1;
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| 104 | G4double kint = rc*sample + b;
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| 105 | G4double theta = (0.5 + kint)*pi/180.;
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| 106 |
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| 107 | // G4int k;
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| 108 | //std::abs(sample-sig[j][ke1]) < std::abs(sample-sig[j][ke2]) ? k = ke1 : k = ke2;
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| 109 | // G4double theta = (0.5 + k)*pi/180.;
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| 110 |
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| 111 | if (verboseLevel > 1) {
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| 112 | G4cout << " energy bin " << je1 << " energy=" << elab[je1] << G4endl;
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| 113 | G4cout << " angle bin " << kint << " angle=" << theta/degree << G4endl;
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| 114 | }
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| 115 | G4double costh= std::cos(theta);
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| 116 | // G4cout << "scattering angle hpw "<<costh<<" "<<s<<" "<<m1<<" "<<m2<<G4endl;
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| 117 | return costh;
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| 118 | }
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| 119 |
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| 120 | G4double G4AngularDistributionPP::Phi() const
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| 121 | {
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| 122 | return twopi * G4UniformRand();
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| 123 | }
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