1 | $Id: README,v 1.10 2006/11/22 18:58:25 vnivanch 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 | TestEm9 |
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9 | ------- |
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10 | Demonstrate electromagnetic physics in crystal calorimeters. |
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11 | How to define cut-per-region. |
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12 | |
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13 | 1- GEOMETRY DEFINITION |
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14 | |
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15 | The geometry consists of the vertex detector (VD), the electromagnetic |
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16 | calorimeter (EM), and the muon identifier (MU). Detector layout along |
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17 | the axis Z. |
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18 | |
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19 | VD consisted of 3 layers of Si with pads structured along the axis X. |
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20 | Between VD and EM there are 2 active absorbers (scintillators). |
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21 | EM is the matrix 5x5 of heavy crystals. MU consist of 2 active absorbers |
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22 | (scintillators) and the iron plate between. |
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23 | |
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24 | 2 additional to the World regions are defined: VertexDetector and |
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25 | MuonDetector. For testing purposes first absorber of MU is included in |
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26 | the region of VD. |
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27 | |
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28 | Material of calorimiter and absorber can be choosen: |
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29 | Air Water lAr Al Fe BGO PbWO4 Pb. |
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30 | eg: /testem/det/CalMat PbWO4 |
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31 | /testem/det/AbsMat Al |
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32 | |
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33 | The size of the detector can be changed also. |
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34 | |
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35 | eg: /testem/det/EcalLength 20 cm |
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36 | /testem/det/EcalWidth 5 cm |
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37 | /testem/det/update ---> rebuild the geometry |
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38 | |
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39 | 2- PHYSICS LISTS |
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40 | |
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41 | Physics Lists are based on modular design. Few modules are instantiated: |
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42 | 1. Transporatation |
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43 | 2. EM physics |
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44 | 3. Decays |
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45 | 4. StepMax - for steplimitation |
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46 | |
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47 | The following options for EM physics are available: |
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48 | - "standard" the best standard EM physics (default) |
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49 | - "G4standard" recommended standard EM physics for LHC |
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50 | - "G4standard_fast" the best CPU performance standard physics for LHC |
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51 | - "G4standard_exp" experimental standard physics for LHC |
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52 | - "Livermore" low-energy EM physics using Livermore data |
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53 | - "Penelope" low-energy EM physics implementing Penelope models |
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54 | |
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55 | Optional components can be added: |
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56 | - "elastic" elastic scattering of hadrons |
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57 | - "binary" QBBC configuration of hadron/ion inelastic models |
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58 | - "gamma_nuc" gamma- and electro-nuclear processes |
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59 | - "stopping" stopping processes |
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60 | |
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61 | 3- AN EVENT : THE PRIMARY GENERATOR |
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62 | |
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63 | The primary kinematic consists of a single particle which hits the |
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64 | cylinder perpendicular to the input face. The type of the particle |
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65 | and its energy are set in the PrimaryGeneratorAction class, and can |
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66 | changed via the G4 build-in commands of ParticleGun class. |
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67 | |
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68 | 4- OUTPUT |
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69 | |
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70 | The batch regime of simulation can be started |
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71 | $G4WORKDIR/bin/$G4SYSTEM/TestEm9 TestEm9.in |
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72 | where TestEm9.in is the example of macro file for batch job. |
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73 | |
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74 | As a result of simulation the number of secondaries produced |
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75 | in different regions are averaged. The average energy depositions |
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76 | in active absorbers and EM as well as RMS of these values are shown. |
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77 | The number of hits in pads of VD is printed out. |
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78 | |
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79 | 5- VISUALISATION |
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80 | |
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81 | To use visualisation the environment variable G4_VIS_USE should be |
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82 | defined. An interactive session starts if no macro file is specified |
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83 | in the command line: |
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84 | $G4WORKDIR/bin/$G4SYSTEM/TestEm9 |
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85 | |
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86 | To start visualisation one can issur |
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87 | >/control/execute vis.mac |
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88 | >/run/beamOn 1 |
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89 | |
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90 | 6- ANALYSIS |
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91 | |
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92 | To create histograms/ntuple for further analysis one should define |
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93 | environment variable G4ANALYSIS_USE and setup local AIDA implementation. |
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94 | The example should be recompiled: |
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95 | |
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96 | gmake histclean |
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97 | gmake |
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98 | |
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99 | The macro file csi.mac can be used as exmple of macro for analysis. It |
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100 | can be executed in the following way: |
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101 | $G4WORKDIR/bin/$G4SYSTEM/TestEm9 csi.mac |
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102 | |
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103 | |
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104 | 7- Using histograms |
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105 | ------------------- |
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106 | |
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107 | By default the histograms are not activated. To activate histograms |
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108 | the environment variable G4ANALYSIS_USE should be defined. For instance |
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109 | uncomment the flag G4ANALYSIS_USE in GNUmakefile. |
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110 | |
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111 | To use histograms any of implementations of AIDA interfaces should |
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112 | be available (see http://aida.freehep.org). |
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113 | |
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114 | A package including AIDA and extended interfaces also using Python |
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115 | is PI, available from: http://cern.ch/pi . |
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116 | |
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117 | Once installed PI or PI-Lite in a specified local area $MYPY, it is |
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118 | required to add the installation path to $PATH, i.e. for example, |
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119 | for release 1.2.1 of PI: |
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120 | |
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121 | setenv PATH ${PATH}:$MYPI/1.2.1/app/releases/PI/PI_1_2_1/rh73_gcc32/bin |
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122 | |
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123 | CERN users can use the PATH to the LCG area on AFS. |
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124 | |
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125 | Before compilation of the example it is optimal to clean up old |
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126 | files: |
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127 | |
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128 | gmake histclean |
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129 | gmake |
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130 | |
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131 | Before running the example the command should be issued: |
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132 | |
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133 | eval `aida-config --runtime csh` |
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134 | |
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135 | It is possible to choose the format of the output file with |
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136 | histograms using UI command: |
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137 | |
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138 | /testem/histo/setFileType type |
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139 | |
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140 | The following types are available: hbook, root, xml. |
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