1 | $Id: README,v 1.1 2001/10/11 07:18:17 grichine 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 | field03 (based on field01) |
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9 | ------------------------- |
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10 | |
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11 | Test for investigation of tracking in magnetic field which is set different |
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12 | depending of selected logical volume |
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13 | |
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14 | |
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15 | 1- GEOMETRY DEFINITION |
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16 | |
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17 | The "absorber" is a solid made of a given material. |
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18 | |
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19 | Three parameters define the absorber : |
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20 | - the material of the absorber, |
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21 | - the thickness of an absorber, |
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22 | - the transverse size of the absorber (the input face is a square). |
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23 | |
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24 | The volume "World" contains the "absorber". |
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25 | In this test the parameters of the "World" can be changed , too. |
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26 | |
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27 | In addition a transverse uniform magnetic field can be applied. |
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28 | |
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29 | The default geometry is constructed in DetectorConstruction class, |
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30 | but all the parameters can be changed via |
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31 | the commands defined in the DetectorMessenger class. |
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32 | |
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33 | 2- AN EVENT : THE PRIMARY GENERATOR |
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34 | |
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35 | The primary kinematic consists of a single particle which hits the |
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36 | absorber perpendicular to the input face. The type of the particle |
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37 | and its energy are set in the PrimaryGeneratorAction class, and can |
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38 | be changed via the G4 build-in commands of ParticleGun class (see |
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39 | the macros provided with this example). |
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40 | |
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41 | A RUN is a set of events. |
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42 | |
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43 | 3- DETECTOR RESPONSE |
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44 | |
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45 | Here we test G4PAIionisation , G4IonisationByLogicalVolume and |
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46 | transition radiation processes |
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47 | |
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48 | A HIT is a record, event per event , of all the |
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49 | informations needed to simulate and analyse the detector response. |
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50 | |
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51 | In this example a CalorHit is defined as a set of 2 informations: |
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52 | - the total energy deposit in the absorber, |
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53 | - the total tracklength of all charged particles in the absorber, |
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54 | |
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55 | Therefore the absorber is declared |
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56 | 'sensitive detector' (SD), which means they can contribute to the hit. |
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57 | |
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58 | At the end of a run, from the histogram(s), one can study |
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59 | different physics quantities such as : |
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60 | - angle distribution, |
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61 | - energy deposit, |
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62 | - transmission/backscattering, |
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63 | - ... |
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64 | |
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65 | The test contains 10 built-in histograms, which can be activated by |
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66 | interactive commands (see the macros runxx.mac for details). |
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67 | The histograms/plots are in printed form in the corresponding |
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68 | resultxx (for GEANT4) and outxx (for GEANT3) files, and they are |
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69 | saved as geant4.plotxx and geant3.plotxx histogram files, too. |
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70 | |
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71 | The histogram files can be viewed using PAW e.g with the commands |
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72 | |
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73 | paw> h/file 1 geant4.plot01 or g4.p11 |
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74 | paw> option stat |
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75 | paw> h/pl 1 |
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76 | |
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77 | |
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78 | |
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79 | 4- PHYSICS DEMO |
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80 | |
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81 | The particle's type and the physic processes which will be available |
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82 | in this example are set in PhysicsList class. |
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83 | |
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84 | The messenger classes introduce interactive commands . Using these |
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85 | commands the geometry of the detector, the data of the primary |
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86 | particle, the limits of the histograms , etc. can be changed. |
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87 | |
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88 | |
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89 | 5- HOW TO START ? |
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90 | |
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91 | - compile and link to generate an executable |
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92 | % cd $G4INSTALL/example/extended/field/field01 |
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93 | % gmake |
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94 | |
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95 | - execute field01 in 'batch' mode from macro files e.g. |
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96 | % $(G4INSTALL)/bin/$(G4SYSTEM)/field01 run11.mac |
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97 | |
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98 | - execute field01 in 'interactive' mode with visualization e.g. |
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99 | % $(G4INSTALL)/bin/$(G4SYSTEM)/field01 |
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100 | .... |
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101 | Idle> type your commands |
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102 | .... |
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103 | |
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104 | 6- GEANT4/GEANT3/exp.data comparison |
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105 | |
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106 | A GEANT4/GEANT3/exp. data comparison is given here for a few cases. |
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107 | |
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108 | The GEANT4 results can be found in the results/ directory, the resultxx |
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109 | output was obtained with the runxx.mac macro. |
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110 | |
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111 | The relevant part of the GEANT3 code is in the geant3/ directory |
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112 | together with the runxx.dat input files. The outputs of the GEANT3 runs |
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113 | geant3/results subdirectory. |
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114 | |
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115 | In order to make an executable of GEANT3 the gmakeB command should be |
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116 | used in the geant3/ subdirectory.To run this executable with a given |
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117 | input file the input file name should be given when it is being asked |
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118 | by the program.(see geant3/README) |
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119 | |
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120 | The expdata/ directory contains some information |
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121 | on the experimental data. |
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122 | |
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123 | |
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124 | List of the built-in histograms |
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125 | ------------------------------- |
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126 | |
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127 | 1. number of (tracking) steps/event |
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128 | 2. energy deposit distribution in the absorber (in MeV) |
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129 | 3. angle distribution of the primary particle at the exit |
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130 | of the absorber (deg) |
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131 | 4. distribution of the lateral displacement at exit(mm) |
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132 | 5. kinetic energy of the transmitted primaries (MeV) |
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133 | 6. angle distribution of the backscattered primaries (deg) |
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134 | 7. kinetic energy of the backscattered primary particles (MeV) |
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135 | 8. kinetic energy of the charged secondary particles (MeV) |
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136 | 9. z distribution of the secondary charged vertices (mm) |
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137 | 10. kinetic energy of the photons escaping the absorber (MeV) |
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138 | |
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