Gabriele Cosmo
135 lines
5.0 KiB
C++
135 lines
5.0 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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#include "G4AngularDistributionNP.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "Randomize.hh"
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#include "G4ios.hh"
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// Initialization of static data arrays:
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#include "G4AngularDistributionNPData.hh"
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#include "Randomize.hh"
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G4double G4AngularDistributionNP::CosTheta(G4double S, G4double m_1, G4double m_2) const
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{
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G4int verboseLevel=1;
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G4double ek= ((S - sqr(m_1) -sqr(m_2) )/(2*m_1) - m_1 )/GeV ; // kinetic energy in GeV
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// Find energy bin
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G4int je1 = 0;
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G4int je2 = NENERGY - 1;
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G4int iterationsLeft=2*NENERGY +1;
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do {
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G4int midBin = (je1 + je2)/2;
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if (ek < elab[midBin])
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je2 = midBin;
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else
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je1 = midBin;
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} while ( (je2 - je1) > 1 && --iterationsLeft > 0 ); /* Loop checking, 30-Oct-2015, G.Folger */
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if ( iterationsLeft <= 0 ) {
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G4Exception("G4AngularDistributionNP", "im_r_matrix010", FatalException,
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"Problem with energy bin (elab) data");
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}
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// G4int j;
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//std::abs(ek-elab[je1]) < std::abs(ek-elab[je2]) ? j = je1 : j = je2;
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G4double delab = elab[je2] - elab[je1];
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// Sample the angle
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G4double sample = G4UniformRand();
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G4int ke1 = 0;
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G4int ke2 = NANGLE - 1;
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G4double dsig = sig[je2][0] - sig[je1][0];
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G4double rc = dsig/delab;
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G4double b = sig[je1][0] - rc*elab[je1];
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G4double sigint1 = rc*ek + b;
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G4double sigint2 = 0.;
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if (verboseLevel > 1) G4cout << "sample=" << sample << G4endl
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<< ek << " " << ke1 << " " << ke2 << " "
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<< sigint1 << " " << sigint2 << G4endl;
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iterationsLeft= 2*NANGLE +1;
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do {
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G4int midBin = (ke1 + ke2)/2;
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dsig = sig[je2][midBin] - sig[je1][midBin];
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rc = dsig/delab;
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b = sig[je1][midBin] - rc*elab[je1];
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G4double sigint = rc*ek + b;
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if (sample < sigint) {
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ke2 = midBin;
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sigint2 = sigint;
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}
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else {
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ke1 = midBin;
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sigint1 = sigint;
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}
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if (verboseLevel > 1)G4cout << ke1 << " " << ke2 << " "
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<< sigint1 << " " << sigint2 << G4endl;
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} while ( (ke2 - ke1) > 1 && --iterationsLeft > 0); /* Loop checking, 30-Oct-2015, G.Folger */
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if ( iterationsLeft <= 0 ) {
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G4Exception("G4AngularDistributionNP", "im_r_matrix011", FatalException,
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"Problem with angular distribution (sig) data");
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}
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// sigint1 and sigint2 should be recoverable from above loop
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// G4double dsig = sig[je2][ke1] - sig[je1][ke1];
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// G4double rc = dsig/delab;
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// G4double b = sig[je1][ke1] - rc*elab[je1];
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// G4double sigint1 = rc*ek + b;
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// G4double dsig = sig[je2][ke2] - sig[je1][ke2];
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// G4double rc = dsig/delab;
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// G4double b = sig[je1][ke2] - rc*elab[je1];
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// G4double sigint2 = rc*ek + b;
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dsig = sigint2 - sigint1;
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rc = 1./dsig;
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b = ke1 - rc*sigint1;
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G4double kint = rc*sample + b;
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G4double theta = (0.5 + kint)*pi/180.;
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// G4int k;
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//std::abs(sample-sig[j][ke1]) < std::abs(sample-sig[j][ke2]) ? k = ke1 : k = ke2;
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// G4double theta = (0.5 + k)*pi/180.;
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if (verboseLevel > 1) {
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G4cout << " energy bin " << je1 << " energy=" << elab[je1] << G4endl;
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G4cout << " angle bin " << kint << " angle=" << theta/degree << G4endl;
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}
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G4double costh= std::cos(theta);
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return costh;
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}
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G4double G4AngularDistributionNP::Phi() const
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{
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return twopi * G4UniformRand();
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}
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