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 | // |
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27 | // |
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28 | #ifndef G4NuclearFermiDensity_h |
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29 | #define G4NuclearFermiDensity_h 1 |
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30 | |
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31 | #include "globals.hh" |
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32 | #include "G4ThreeVector.hh" |
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33 | #include "G4VNuclearDensity.hh" |
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34 | |
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35 | #include <CLHEP/Units/PhysicalConstants.h> // pi, fermi,.. |
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36 | #include <cmath> // pow |
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37 | |
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38 | class G4NuclearFermiDensity : public G4VNuclearDensity |
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39 | { |
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40 | |
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41 | public: |
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42 | G4NuclearFermiDensity(G4double anA, G4double aZ); |
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43 | ~G4NuclearFermiDensity(); |
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44 | |
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45 | G4double GetRelativeDensity(const G4ThreeVector & aPosition) const |
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46 | { |
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47 | return 1./(1.+std::exp((aPosition.mag()-theR)/a)); |
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48 | } |
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49 | |
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50 | G4double GetRadius(const G4double maxRelativeDenisty) const |
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51 | { |
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52 | return (maxRelativeDenisty>0 && maxRelativeDenisty <= 1 ) ? |
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53 | (theR + a*std::log((1-maxRelativeDenisty+std::exp(-1*theR/a))/maxRelativeDenisty)) : DBL_MAX; |
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54 | } |
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55 | |
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56 | G4double GetDeriv(const G4ThreeVector & aPosition) const |
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57 | { |
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58 | G4double currentR=aPosition.mag(); |
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59 | if (currentR > 40*theR ) {return 0;} |
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60 | else return -std::exp((currentR-theR)/a) * sqr(GetDensity(aPosition)) / (a*Getrho0()); |
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61 | } |
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62 | |
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63 | private: |
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64 | |
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65 | G4int theA; |
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66 | G4int theZ; |
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67 | G4double theR; // Nuclear Radius |
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68 | const G4double a; // Determines the nuclear surface thickness |
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69 | |
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70 | }; |
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71 | |
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72 | #endif |
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73 | |
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