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 | // This software was developed by Lawrence Livermore National Laboratory. |
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28 | // |
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29 | // Redistribution and use in source and binary forms, with or without |
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30 | // modification, are permitted provided that the following conditions are met: |
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31 | // |
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32 | // 1. Redistributions of source code must retain the above copyright notice, |
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33 | // this list of conditions and the following disclaimer. |
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34 | // 2. Redistributions in binary form must reproduce the above copyright notice, |
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35 | // this list of conditions and the following disclaimer in the documentation |
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36 | // and/or other materials provided with the distribution. |
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37 | // 3. The name of the author may not be used to endorse or promote products |
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38 | // derived from this software without specific prior written permission. |
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39 | // |
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40 | // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
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41 | // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
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42 | // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
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43 | // EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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44 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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45 | // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
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46 | // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
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47 | // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
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48 | // OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
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49 | // ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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50 | // |
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51 | // Copyright (c) 2006 The Regents of the University of California. |
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52 | // All rights reserved. |
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53 | // UCRL-CODE-224807 |
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54 | // |
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55 | // |
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56 | // $Id: G4SmpNVel.cc,v 1.2 2007/06/01 13:46:53 gcosmo Exp $ |
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57 | // |
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58 | |
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59 | #include <cmath> |
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60 | #include "G4fissionEvent.hh" |
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61 | |
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62 | G4double G4fissionEvent::G4SmpNVel(G4double eng, G4double* cosdiru, G4double* cosdirv, G4double* cosdirw) { |
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63 | |
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64 | /* |
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65 | Description |
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66 | Knowing the neutron energy, determine its velocity and the 3 direction cosines |
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67 | */ |
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68 | |
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69 | /* |
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70 | Input |
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71 | eng - energy of neutron |
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72 | Output |
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73 | - velocity |
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74 | - 3 components of the neutron velocity |
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75 | in arguments (cosdiru, cosdirv, cosdirw) |
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76 | */ |
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77 | |
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78 | const G4double rme = 939.56563; /* Rest Mass Energy equivalents for neutrons (MeV) */ |
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79 | const G4double cspeed = 2.99792458e+8; /* speed of light (m/sec) */ |
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80 | |
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81 | G4double vel; |
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82 | G4double ratio = eng/rme; |
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83 | |
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84 | if (ratio > 1.e-8) { |
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85 | /* Relativistic vel calculation */ |
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86 | vel = cspeed*std::sqrt(1.-rme*rme/((rme+eng)*(rme+eng))); |
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87 | } else { |
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88 | /* Non-relativistic vel calculation */ |
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89 | vel = cspeed*std::sqrt(2.*eng/rme); |
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90 | } |
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91 | |
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92 | G4SmpIsoDir(cosdiru, cosdirv, cosdirw); |
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93 | |
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94 | return vel; |
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95 | } |
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