1 | $Id: README,v 1.11 2009/09/22 14:20:31 maire Exp $ |
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2 | ------------------------------------------------------------------- |
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3 | |
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4 | ========================================================= |
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5 | Geant4 - an Object-Oriented Toolkit for Simulation in HEP |
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6 | ========================================================= |
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7 | |
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8 | TestEm11 |
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9 | ------- |
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10 | |
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11 | How to plot a depth dose profile in a rectangular box. |
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12 | |
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13 | |
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14 | 1- GEOMETRY DEFINITION |
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15 | |
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16 | The geometry consists of a single block of an homogenous material. |
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17 | Optionally, the block can be divided in thinner layers (replica) |
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18 | |
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19 | 4 parameters define the geometry : |
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20 | - the material of the box, |
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21 | - the thickness of the box (sizeX), |
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22 | - the tranverse dimension of the box (sizeYZ). |
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23 | - the number of layers (nbOfLayers) |
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24 | |
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25 | In addition a transverse uniform magnetic field can be applied. |
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26 | |
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27 | The default geometry is constructed in DetectorConstruction class, |
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28 | but all of the above parameters can be changed interactively via |
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29 | the commands defined in the DetectorMessenger class. |
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30 | |
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31 | 2- PHYSICS LIST |
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32 | |
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33 | Physics lists can be local (eg. in this example) or from G4 kernel |
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34 | physics_lists subdirectory. |
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35 | |
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36 | Local physics lists: |
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37 | - "local" standard EM physics with current 'best' options setting. |
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38 | these options are explicited in PhysListEmStandard |
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39 | |
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40 | From geant4/source/physics_lists/builders: |
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41 | - "emstandard_opt0" recommended standard EM physics for LHC |
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42 | - "emstandard_opt1" best CPU performance standard physics for LHC |
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43 | - "emstandard_opt2" |
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44 | - "emstandard_opt3" best current advanced EM options. |
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45 | analog to "local" above |
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46 | - "emlivermore" low-energy EM physics using Livermore data |
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47 | - "empenelope" low-energy EM physics implementing Penelope models |
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48 | |
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49 | Physics lists and options can be (re)set with UI commands |
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50 | |
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51 | Please, notice that options set through G4EmProcessOPtions are global, eg |
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52 | for all particle types. In G4 builders, it is shown how to set options per |
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53 | particle type. |
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54 | |
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55 | |
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56 | 3- AN EVENT : THE PRIMARY GENERATOR |
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57 | |
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58 | The primary kinematic consists of a single particle starting at the |
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59 | left face of the box. The type of the particle and its energy are set |
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60 | in the PrimaryGeneratorAction class, and can be changed via the G4 |
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61 | build-in commands of ParticleGun class (see the macros provided with |
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62 | this example). |
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63 | |
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64 | In addition one can choose randomly the impact point of the incident |
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65 | particle. The corresponding interactive command is built in |
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66 | PrimaryGeneratorMessenger class. |
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67 | |
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68 | A RUN is a set of events. |
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69 | |
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70 | |
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71 | 4- VISUALIZATION |
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72 | |
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73 | The Visualization Manager is set in the main(). |
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74 | The initialisation of the drawing is done via the commands |
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75 | /vis/... in the macro vis.mac. To get visualisation: |
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76 | > /control/execute vis.mac |
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77 | |
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78 | The detector has a default view which is a longitudinal view of the |
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79 | box. |
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80 | |
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81 | The tracks are drawn at the end of event, and erased at the end of run. |
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82 | Optionaly one can choose to draw all particles, only the charged one, |
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83 | or none. This command is defined in EventActionMessenger class. |
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84 | |
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85 | |
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86 | 5- HOW TO START ? |
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87 | |
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88 | - compile and link to generate an executable |
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89 | % cd geant4/examples/extended/electromagnetic/TestEm1 |
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90 | % gmake |
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91 | |
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92 | - execute TestEm11 in 'batch' mode from macro files |
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93 | % TestEm11 run01.mac |
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94 | |
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95 | - execute TestEm11 in 'interactive mode' with visualization |
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96 | % TestEm11 |
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97 | .... |
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98 | Idle> type your commands |
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99 | .... |
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100 | Idle> exit |
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101 | |
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102 | |
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103 | 6- TRACKING and STEP MAX |
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104 | |
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105 | Testem11 computes the total energy deposited along the trajectory of |
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106 | the incident particle : the so-called longitudinal energy profile, |
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107 | or depth dose distribution. |
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108 | The energy deposited (edep) is randomly distribued along the step (see |
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109 | SteppingAction). |
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110 | |
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111 | In order to control the accuracy of the deposition, the maximum step size |
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112 | of charged particles is computed automatically from the binning of |
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113 | histogram 1 and 8 (see HistoManager). |
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114 | |
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115 | As an example, this limitation is implemented as a 'full' process : |
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116 | see StepMax class and its Messenger. The 'StepMax process' is registered |
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117 | in the Physics List. |
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118 | |
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119 | In RunAction::BeginOfRun() the stepMax value is passed from the |
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120 | HistoManager to the StepMax process. |
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121 | A boolean UI command allows to desactivate this mechanism. |
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122 | |
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123 | 7- HISTOGRAMS |
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124 | |
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125 | Testem11 has several predefined 1D histograms : |
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126 | |
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127 | 1 : longitudinal energy profile (in MeV/mm and per event) |
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128 | 2 : total energy deposited in the absorber |
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129 | 3 : total track length of the primary track |
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130 | 4 : step size of the primary track |
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131 | 5 : projected range of the primary track |
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132 | 6 : total track length of charged secondary tracks |
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133 | 7 : step size of charged secondary tracks |
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134 | 8 : longitudinal energy profile (in MeV.cm2/g), as a function of x/r0 |
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135 | where r0 is the range of the primary particle |
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136 | |
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137 | The histograms are managed by the HistoManager class and its Messenger. |
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138 | The histos can be individually activated with the command : |
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139 | /testem/histo/setHisto id nbBins valMin valMax unit |
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140 | where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..) |
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141 | |
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142 | One can control the name of the histograms file with the command: |
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143 | /testem/histo/setFileName name (default testem11) |
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144 | |
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145 | It is possible to choose the format of the histogram file (hbook, root, XML) |
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146 | with the command /testem/histo/setFileType (root by default) |
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147 | |
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148 | It is also possible to print selected histograms on an ascii file: |
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149 | /testem/histo/printHisto id |
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150 | All selected histos will be written on a file name.ascii (default testem11) |
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151 | |
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152 | Note that, by default, histograms are disabled. To activate them, uncomment |
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153 | the flag G4ANALYSIS_USE in GNUmakefile. |
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154 | |
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155 | |
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156 | 8- USING HISTOGRAMS |
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157 | |
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158 | To use histograms, at least one of the AIDA implementations should be |
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159 | available. See InstallAida.txt |
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