[1211] | 1 | \section{Introduction} \label{em_disc} |
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| 2 | |
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| 3 | All processes of gamma interaction with media in Geant4 are happen at the |
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| 4 | end of the step, so are following $G4VDiscreteProcess$ interface. There are |
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| 5 | a number of similar functions for discrete electromagnetic processes and in the Standard |
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| 6 | electromagnetic (EM) package an additional base classes are designed to provide |
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| 7 | common computations \cite{discrete.em}. |
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| 8 | |
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| 9 | \subsection{General Interfaces} |
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| 10 | |
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| 11 | Common calculations are performed in the class $G4VEmProcess$ in which |
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| 12 | the following public methods are implemented: |
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| 13 | \begin{itemize} |
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| 14 | \item |
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| 15 | PrintInfoDefinition; |
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| 16 | \item |
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| 17 | PreparePhysicsTable; |
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| 18 | \item |
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| 19 | BuildPhysicsTable; |
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| 20 | \item |
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| 21 | PostStepDoIt; |
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| 22 | \item |
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| 23 | StorePhysicsTable; |
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| 24 | \item |
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| 25 | RetrievePhysicsTable; |
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| 26 | \item |
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| 27 | MeanFreePath; |
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| 28 | \item |
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| 29 | PostStepGetPhysicalInteractionLength; |
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| 30 | \item |
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| 31 | MicroscopicCrossSection; |
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| 32 | \item |
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| 33 | AddEmModel; |
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| 34 | \item |
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| 35 | SetEmModel; |
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| 36 | \item |
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| 37 | UpdateEmModel; |
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| 38 | \item |
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| 39 | SelectModelForMaterial; |
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| 40 | \item |
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| 41 | LambdaTable; |
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| 42 | \end{itemize} |
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| 43 | There are many Get/Set and other accessors methods implemented for this base class. |
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| 44 | Any derive class need to have an implementation of pure virtual methods: |
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| 45 | \begin{itemize} |
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| 46 | \item |
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| 47 | IsApplicable; |
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| 48 | \item |
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| 49 | PrintInfo; |
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| 50 | \item |
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| 51 | InitialiseProcess; |
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| 52 | \end{itemize} |
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| 53 | This interface is used by the following processes: |
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| 54 | \begin{itemize} |
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| 55 | \item |
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| 56 | G4ComptonScattering; |
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| 57 | \item |
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| 58 | G4CoulombScattering; |
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| 59 | \item |
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| 60 | G4GammaConversion; |
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| 61 | \item |
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| 62 | G4eplusAnnihilation (additionally AtRest methods are provided); |
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| 63 | \item |
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| 64 | G4eeToHadrons; |
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| 65 | \item |
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| 66 | G4PolarizedCompton; |
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| 67 | \item |
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| 68 | G4PolarizedGammaConversion; |
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| 69 | \item |
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| 70 | G4PolarizedPhotoElectricEffect; |
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| 71 | \item |
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| 72 | G4eplusPolarizedAnnihilation (additionally AtRest methods are provided); |
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| 73 | \end{itemize} |
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| 74 | These processes mainly provide initialization and also some generic functions |
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| 75 | like $PostStepDoIt$. The physics models are |
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| 76 | implemented using the $G4VEmModel$ interface. Because a model is defined to |
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| 77 | be active over a given energy range and for a defined set of $G4Region$s, |
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| 78 | an energy loss process can have one or several models defined for a particle |
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| 79 | and $G4Region$. The following models from {\it standard, lowenergy, and polarisation} |
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| 80 | libraries are available for above list of processes: |
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| 81 | \begin{itemize} |
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| 82 | \item |
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| 83 | G4BetheHeitlerModel; |
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| 84 | \item |
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| 85 | G4CoulombScatteringModel; |
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| 86 | \item |
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| 87 | G4eCoulombScatteringModel; |
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| 88 | \item |
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| 89 | G4eeToHadronsModel; |
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| 90 | \item |
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| 91 | G4DummyModel (zero cross section, no secondaries); |
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| 92 | \item |
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| 93 | G4KleinNishinaCompton; |
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| 94 | \item |
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| 95 | G4LivermoreComptonModel; |
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| 96 | \item |
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| 97 | G4LivermoreGammaConversionModel; |
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| 98 | \item |
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| 99 | G4LivermorePhotoElectricModel; |
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| 100 | \item |
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| 101 | G4LivermorePolarizedComptonModel; |
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| 102 | \item |
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| 103 | G4LivermorePolarizedRayleighModel; |
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| 104 | \item |
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| 105 | G4LivermoreRayleighModel; |
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| 106 | \item |
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| 107 | G4PenelopePhotoElectricModel; |
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| 108 | \item |
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| 109 | G4PenelopeRayleighModel; |
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| 110 | \item |
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| 111 | G4PEEffectModel; |
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| 112 | \item |
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| 113 | G4PenelopeAnnihilationModel; |
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| 114 | \item |
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| 115 | G4PenelopeComptonModel; |
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| 116 | \item |
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| 117 | G4PenelopeGammaConversionModel; |
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| 118 | \item |
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| 119 | G4PolarizedAnnihilationModel; |
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| 120 | \item |
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| 121 | G4PolarizedComptonModel; |
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| 122 | \item |
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| 123 | G4PolarizedGammaConversionModel; |
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| 124 | \item |
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| 125 | G4PolarizedPEEffectModel; |
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| 126 | \item |
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| 127 | G4WentzelVIModel; |
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| 128 | \end{itemize} |
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| 129 | Some processes from {\it standard} library do not follow |
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| 130 | described interfaces but provide direct implementations |
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| 131 | of the basic $G4VDiscreteProcess$ process: |
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| 132 | \begin{itemize} |
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| 133 | \item |
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| 134 | G4GammaConversionToMuons; |
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| 135 | \item |
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| 136 | G4AnnihiToMuPair; |
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| 137 | \item |
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| 138 | G4ScreenedNuclearRecoil; |
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| 139 | \item |
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| 140 | G4Cerenkov; |
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| 141 | \item |
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| 142 | G4Scintillation; |
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| 143 | \item |
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| 144 | G4SynchrotronRadiation; |
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| 145 | \end{itemize} |
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| 146 | |
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| 147 | |
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| 148 | \subsection{Status of this document} |
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| 149 | 06.12.07 created by V.Ivanchenko \\ |
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| 150 | 11.12.08 extended list of models by V.Ivanchenko \\ |
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| 151 | |
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| 152 | \begin{latexonly} |
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| 153 | |
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| 154 | \begin{thebibliography}{99} |
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| 155 | \bibitem{discrete.em} H.~Burkhardt et al., |
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| 156 | Geant4 standard electromagnetic package for HEP applications. |
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| 157 | {\em Nuclear Science Symposium Conference Record 2004, IEEE, Volume 3, |
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| 158 | Oct 2004. pp. 1907-1910.} |
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| 159 | \end{thebibliography} |
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| 160 | |
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| 161 | \end{latexonly} |
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| 162 | |
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| 163 | \begin{htmlonly} |
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| 164 | |
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| 165 | \subsection{Bibliography} |
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| 166 | |
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| 167 | \begin{enumerate} |
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| 168 | \item H.~Burkhardt et al., |
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| 169 | Geant4 standard electromagnetic package for HEP applications. |
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| 170 | {\em Nuclear Science Symposium Conference Record 2004, IEEE, Volume 3, |
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| 171 | Oct 2004. pp. 1907-1910.} |
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| 172 | \end{enumerate} |
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| 173 | |
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| 174 | \end{htmlonly} |
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