| 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 | // $Id: G4BigBanger.cc,v 1.29 2010/05/21 17:56:34 mkelsey Exp $ |
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| 26 | // Geant4 tag: $Name: geant4-09-04-beta-cand-01 $ |
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| 27 | // |
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| 28 | // 20100114 M. Kelsey -- Remove G4CascadeMomentum, use G4LorentzVector directly |
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| 29 | // 20100301 M. Kelsey -- In generateBangInSCM(), restore old G4CascMom calcs. |
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| 30 | // for (N-1)th outgoing nucleon. |
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| 31 | // 20100319 M. Kelsey -- Use new generateWithRandomAngles for theta,phi stuff |
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| 32 | // 20100407 M. Kelsey -- Replace std::vector<> returns with data members. |
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| 33 | // 20100413 M. Kelsey -- Pass G4CollisionOutput by ref to ::collide() |
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| 34 | // 20100517 M. Kelsey -- Inherit from common base class, clean up code |
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| 35 | |
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| 36 | #include "G4BigBanger.hh" |
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| 37 | #include "G4CollisionOutput.hh" |
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| 38 | #include "G4InuclNuclei.hh" |
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| 39 | #include "G4InuclElementaryParticle.hh" |
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| 40 | #include "G4InuclSpecialFunctions.hh" |
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| 41 | #include "G4ParticleLargerEkin.hh" |
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| 42 | #include "G4LorentzConvertor.hh" |
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| 43 | #include "G4HadTmpUtil.hh" |
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| 44 | #include "G4NucleiProperties.hh" |
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| 45 | #include <algorithm> |
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| 46 | |
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| 47 | using namespace G4InuclSpecialFunctions; |
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| 48 | |
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| 49 | typedef std::vector<G4InuclElementaryParticle>::iterator particleIterator; |
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| 50 | |
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| 51 | G4BigBanger::G4BigBanger() : G4VCascadeCollider("G4BigBanger") {} |
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| 52 | |
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| 53 | void |
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| 54 | G4BigBanger::collide(G4InuclParticle* /*bullet*/, G4InuclParticle* target, |
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| 55 | G4CollisionOutput& output) { |
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| 56 | |
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| 57 | if (verboseLevel > 3) { |
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| 58 | G4cout << " >>> G4BigBanger::collide" << G4endl; |
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| 59 | } |
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| 60 | |
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| 61 | // primitive explosion model A -> nucleons to prevent too exotic evaporation |
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| 62 | |
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| 63 | const G4double small_ekin = 1.0e-6; |
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| 64 | |
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| 65 | G4LorentzVector totscm; |
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| 66 | G4LorentzVector totlab; |
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| 67 | |
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| 68 | G4InuclNuclei* nuclei_target = dynamic_cast<G4InuclNuclei*>(target); |
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| 69 | if (!nuclei_target) { |
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| 70 | G4cerr << " BigBanger -> try to bang not nuclei " << G4endl; |
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| 71 | return; |
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| 72 | } |
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| 73 | |
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| 74 | G4double A = nuclei_target->getA(); |
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| 75 | G4double Z = nuclei_target->getZ(); |
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| 76 | G4LorentzVector PEX = nuclei_target->getMomentum(); |
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| 77 | G4double EEXS = nuclei_target->getExitationEnergy(); |
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| 78 | G4InuclElementaryParticle dummy(small_ekin, 1); |
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| 79 | G4LorentzConvertor toTheNucleiSystemRestFrame; |
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| 80 | |
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| 81 | toTheNucleiSystemRestFrame.setBullet(dummy); |
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| 82 | toTheNucleiSystemRestFrame.setTarget(nuclei_target); |
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| 83 | toTheNucleiSystemRestFrame.toTheTargetRestFrame(); |
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| 84 | |
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| 85 | G4double etot = (EEXS - G4NucleiProperties::GetBindingEnergy(G4lrint(A), G4lrint(Z) ) ) * MeV/GeV; // To Bertini units |
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| 86 | if (etot < 0.0) etot = 0.0; |
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| 87 | |
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| 88 | if (verboseLevel > 2) { |
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| 89 | G4cout << " BigBanger: target " << G4endl; |
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| 90 | nuclei_target->printParticle(); |
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| 91 | G4cout << " BigBanger: a " << A << " z " << Z << " eexs " << EEXS << " etot " << |
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| 92 | etot << " nm " << nuclei_target->getMass() << G4endl; |
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| 93 | } |
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| 94 | |
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| 95 | generateBangInSCM(etot, A, Z); |
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| 96 | |
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| 97 | if (verboseLevel > 2) { |
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| 98 | G4cout << " particles " << particles.size() << G4endl; |
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| 99 | for(G4int i = 0; i < G4int(particles.size()); i++) |
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| 100 | particles[i].printParticle(); |
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| 101 | } |
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| 102 | |
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| 103 | if(!particles.empty()) { // convert back to Lab |
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| 104 | particleIterator ipart; |
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| 105 | |
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| 106 | for(ipart = particles.begin(); ipart != particles.end(); ipart++) { |
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| 107 | if (verboseLevel > 2) { |
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| 108 | totscm += ipart->getMomentum(); |
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| 109 | } |
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| 110 | G4LorentzVector mom = |
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| 111 | toTheNucleiSystemRestFrame.backToTheLab(ipart->getMomentum()); |
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| 112 | ipart->setMomentum(mom); |
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| 113 | |
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| 114 | if (verboseLevel > 2) { |
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| 115 | mom = ipart->getMomentum(); |
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| 116 | totlab += mom; |
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| 117 | } |
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| 118 | } |
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| 119 | |
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| 120 | std::sort(particles.begin(), particles.end(), G4ParticleLargerEkin()); |
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| 121 | |
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| 122 | if (verboseLevel > 2) { |
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| 123 | G4cout << " In SCM: total outgoing momentum " << G4endl |
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| 124 | << " E " << totscm.e() << " px " << totscm.x() |
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| 125 | << " py " << totscm.y() << " pz " << totscm.z() << G4endl; |
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| 126 | G4cout << " In Lab: mom cons " << G4endl |
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| 127 | << " E " << PEX.e() + 0.001 * EEXS - totlab.e() |
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| 128 | << " px " << PEX.x() - totlab.x() |
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| 129 | << " py " << PEX.y() - totlab.y() |
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| 130 | << " pz " << PEX.z() - totlab.z() << G4endl; |
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| 131 | } |
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| 132 | } |
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| 133 | |
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| 134 | output.addOutgoingParticles(particles); |
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| 135 | |
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| 136 | return; |
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| 137 | } |
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| 138 | |
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| 139 | void G4BigBanger::generateBangInSCM(G4double etot, G4double a, G4double z) { |
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| 140 | if (verboseLevel > 3) { |
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| 141 | G4cout << " >>> G4BigBanger::generateBangInSCM" << G4endl; |
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| 142 | } |
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| 143 | |
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| 144 | // Proton and neutron masses |
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| 145 | const G4double mp = G4InuclElementaryParticle::getParticleMass(1); |
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| 146 | const G4double mn = G4InuclElementaryParticle::getParticleMass(2); |
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| 147 | |
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| 148 | const G4double ang_cut = 0.9999; |
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| 149 | const G4int itry_max = 1000; |
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| 150 | |
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| 151 | G4int ia = int(a + 0.1); |
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| 152 | G4int iz = int(z + 0.1); |
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| 153 | |
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| 154 | if (verboseLevel > 2) { |
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| 155 | G4cout << " ia " << ia << " iz " << iz << G4endl; |
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| 156 | } |
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| 157 | |
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| 158 | particles.clear(); // Reset output vector before filling |
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| 159 | |
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| 160 | if(ia == 1) { |
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| 161 | // abnormal situation |
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| 162 | G4double m = iz > 0 ? mp : mn; |
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| 163 | G4double pmod = std::sqrt((etot + 2.0 * m) * etot); |
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| 164 | G4LorentzVector mom = generateWithRandomAngles(pmod, m); |
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| 165 | |
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| 166 | G4int knd = iz > 0 ? 1 : 2; |
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| 167 | |
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| 168 | particles.push_back(G4InuclElementaryParticle(mom, knd, 8)); // modelId included |
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| 169 | |
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| 170 | return; |
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| 171 | }; |
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| 172 | |
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| 173 | generateMomentumModules(etot, a, z); |
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| 174 | G4bool bad = true; |
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| 175 | G4int itry = 0; |
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| 176 | |
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| 177 | while(bad && itry < itry_max) { |
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| 178 | itry++; |
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| 179 | std::vector<G4LorentzVector> scm_momentums; |
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| 180 | G4LorentzVector tot_mom; |
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| 181 | |
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| 182 | if(ia == 2) { |
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| 183 | // FIXME: This isn't actually a correct four-vector, wrong mass! |
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| 184 | G4LorentzVector mom = generateWithRandomAngles(momModules[0]); |
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| 185 | |
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| 186 | tot_mom += mom; |
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| 187 | |
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| 188 | scm_momentums.push_back(mom); |
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| 189 | |
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| 190 | G4LorentzVector mom1 = -mom; |
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| 191 | |
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| 192 | scm_momentums.push_back(mom1); |
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| 193 | bad = false; |
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| 194 | } else { |
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| 195 | for(G4int i = 0; i < ia - 2; i++) { |
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| 196 | // FIXME: This isn't actually a correct four-vector, wrong mass! |
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| 197 | G4LorentzVector mom = generateWithRandomAngles(momModules[i]); |
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| 198 | |
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| 199 | tot_mom += mom; |
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| 200 | |
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| 201 | scm_momentums.push_back(mom); |
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| 202 | }; |
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| 203 | |
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| 204 | // handle last two |
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| 205 | G4double tot_mod = tot_mom.rho(); |
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| 206 | G4double ct = -0.5 * (tot_mod * tot_mod + momModules[ia - 2] * momModules[ia - 2] - |
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| 207 | momModules[ia - 1] * momModules[ia - 1]) / tot_mod / momModules[ia - 2]; |
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| 208 | |
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| 209 | if (verboseLevel > 2) { |
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| 210 | G4cout << " ct last " << ct << G4endl; |
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| 211 | } |
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| 212 | |
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| 213 | if(std::fabs(ct) < ang_cut) { |
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| 214 | // FIXME: These are not actually four-vectors, just three-momenta |
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| 215 | G4LorentzVector mom2 = generateWithFixedTheta(ct, momModules[ia - 2]); |
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| 216 | // rotate to the normal system |
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| 217 | G4LorentzVector apr = tot_mom/tot_mod; |
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| 218 | G4double a_tr = std::sqrt(apr.x()*apr.x() + apr.y()*apr.y()); |
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| 219 | G4LorentzVector mom; |
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| 220 | mom.setX(mom2.z()*apr.x() + ( mom2.x()*apr.y() + mom2.y()*apr.z()*apr.x())/a_tr); |
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| 221 | mom.setY(mom2.z()*apr.y() + (-mom2.x()*apr.x() + mom2.y()*apr.z()*apr.y())/a_tr); |
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| 222 | mom.setZ(mom2.z()*apr.z() - mom2.y()*a_tr); |
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| 223 | |
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| 224 | scm_momentums.push_back(mom); |
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| 225 | // and the last one |
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| 226 | G4LorentzVector mom1= - mom - tot_mom; |
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| 227 | scm_momentums.push_back(mom1); |
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| 228 | bad = false; |
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| 229 | }; |
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| 230 | }; |
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| 231 | if(!bad) { |
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| 232 | for(G4int i = 0; i < ia; i++) { |
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| 233 | G4int knd = i < iz ? 1 : 2; |
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| 234 | |
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| 235 | particles.push_back(G4InuclElementaryParticle(scm_momentums[i], knd, 8)); |
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| 236 | }; |
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| 237 | }; |
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| 238 | }; |
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| 239 | if (verboseLevel > 2) { |
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| 240 | if(itry == itry_max) G4cout << " BigBanger -> can not generate bang " << G4endl; |
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| 241 | } |
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| 242 | |
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| 243 | return; |
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| 244 | } |
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| 245 | |
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| 246 | void G4BigBanger::generateMomentumModules(G4double etot, G4double a, G4double z) { |
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| 247 | if (verboseLevel > 3) { |
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| 248 | G4cout << " >>> G4BigBanger::generateMomentumModules" << G4endl; |
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| 249 | } |
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| 250 | |
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| 251 | // Proton and neutron masses |
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| 252 | const G4double mp = G4InuclElementaryParticle::getParticleMass(1); |
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| 253 | const G4double mn = G4InuclElementaryParticle::getParticleMass(2); |
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| 254 | |
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| 255 | momModules.clear(); // Reset buffer for filling |
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| 256 | |
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| 257 | G4int ia = G4int(a + 0.1); |
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| 258 | G4int iz = G4int(z + 0.1); |
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| 259 | |
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| 260 | G4double xtot = 0.0; |
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| 261 | G4double promax = maxProbability(a); |
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| 262 | |
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| 263 | G4int i; |
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| 264 | for(i = 0; i < ia; i++) { |
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| 265 | G4double x = generateX(ia, a, promax); |
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| 266 | |
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| 267 | if (verboseLevel > 2) { |
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| 268 | G4cout << " i " << i << " x " << x << G4endl; |
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| 269 | } |
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| 270 | momModules.push_back(x); |
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| 271 | xtot += x; |
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| 272 | }; |
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| 273 | for(i = 0; i < ia; i++) { |
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| 274 | G4double m = i < iz ? mp : mn; |
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| 275 | |
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| 276 | momModules[i] = momModules[i] * etot / xtot; |
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| 277 | momModules[i] = std::sqrt(momModules[i] * (momModules[i] + 2.0 * m)); |
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| 278 | |
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| 279 | if (verboseLevel > 2) { |
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| 280 | G4cout << " i " << i << " pmod " << momModules[i] << G4endl; |
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| 281 | } |
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| 282 | }; |
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| 283 | |
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| 284 | return; |
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| 285 | } |
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| 286 | |
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| 287 | G4double G4BigBanger::xProbability(G4double x, G4int ia) const { |
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| 288 | |
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| 289 | |
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| 290 | if (verboseLevel > 3) { |
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| 291 | G4cout << " >>> G4BigBanger::xProbability" << G4endl; |
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| 292 | } |
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| 293 | |
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| 294 | G4int ihalf = ia / 2; |
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| 295 | G4double ekpr = 0.0; |
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| 296 | |
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| 297 | if(x < 1.0 || x > 0.0) { |
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| 298 | ekpr = x * x; |
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| 299 | |
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| 300 | if(2 * ihalf == ia) { // even A |
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| 301 | ekpr *= std::sqrt(1.0 - x) * std::pow((1.0 - x), G4int(G4double(3 * ia - 6) / 2.0)); |
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| 302 | } |
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| 303 | else { |
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| 304 | ekpr *= std::pow((1.0 - x), G4int(G4double(3 * ia - 5) / 2.0)); |
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| 305 | }; |
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| 306 | }; |
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| 307 | |
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| 308 | return ekpr; |
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| 309 | } |
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| 310 | |
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| 311 | G4double G4BigBanger::maxProbability(G4double a) const { |
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| 312 | |
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| 313 | if (verboseLevel > 3) { |
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| 314 | G4cout << " >>> G4BigBanger::maxProbability" << G4endl; |
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| 315 | } |
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| 316 | |
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| 317 | return xProbability(1.0 / (a - 1.0) / 1.5, G4int(a + 0.1)); |
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| 318 | } |
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| 319 | |
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| 320 | G4double G4BigBanger::generateX(G4int ia, |
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| 321 | G4double a, |
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| 322 | G4double promax) const { |
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| 323 | |
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| 324 | if (verboseLevel > 3) { |
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| 325 | G4cout << " >>> G4BigBanger::generateX" << G4endl; |
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| 326 | } |
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| 327 | |
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| 328 | const G4int itry_max = 1000; |
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| 329 | G4int itry = 0; |
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| 330 | G4double x; |
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| 331 | |
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| 332 | while(itry < itry_max) { |
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| 333 | itry++; |
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| 334 | x = inuclRndm(); |
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| 335 | |
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| 336 | if(xProbability(x, ia) >= promax * inuclRndm()) return x; |
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| 337 | }; |
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| 338 | if (verboseLevel > 2) { |
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| 339 | G4cout << " BigBanger -> can not generate x " << G4endl; |
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| 340 | } |
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| 341 | |
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| 342 | return maxProbability(a); |
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| 343 | } |
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