| 1 | $Id: README,v 1.11 2009/09/22 15:18:20 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 | TestEm12 |
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| 9 | -------- |
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| 10 | |
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| 11 | |
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| 12 | How to plot a depth dose profile in spherical geometry. |
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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 geometry consists of a single sphere of an homogenous material. |
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| 18 | Optionally, the sphere can be divided in thin shells. |
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| 19 | |
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| 20 | 3 parameters define the geometry : |
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| 21 | - the material of the sphere, |
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| 22 | - the radius of the sphere (absorRadius), |
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| 23 | - the number of shells (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 | |
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| 39 | From geant4/source/physics_lists/builders: |
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| 40 | - "emstandard_opt0" recommended standard EM physics for LHC |
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| 41 | - "emstandard_opt1" best CPU performance standard physics for LHC |
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| 42 | - "emstandard_opt2" |
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| 43 | - "emstandard_opt3" best current advanced EM options. |
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| 44 | analog to "local" above |
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| 45 | - "emlivermore" low-energy EM physics using Livermore data |
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| 46 | - "empenelope" low-energy EM physics implementing Penelope models |
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| 47 | |
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| 48 | Physics lists and options can be (re)set with UI commands |
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| 49 | |
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| 50 | Please, notice that options set through G4EmProcessOPtions are global, eg |
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| 51 | for all particle types. In G4 builders, it is shown how to set options per |
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| 52 | particle type. |
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| 53 | |
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| 54 | |
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| 55 | 3- AN EVENT : THE PRIMARY GENERATOR |
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| 56 | |
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| 57 | The primary kinematic consists of a single particle randomly shooted at |
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| 58 | the centre of the sphere. The type of the particle and its energy are set |
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| 59 | in the PrimaryGeneratorAction class, and can be changed via the G4 |
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| 60 | build-in commands of ParticleGun class (see the macros provided with |
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| 61 | this example). |
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| 62 | |
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| 63 | In addition one can desactivate the randomness of the direction of the |
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| 64 | incident particle. The corresponding interactive command is built in |
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| 65 | PrimaryGeneratorMessenger class. |
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| 66 | |
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| 67 | A RUN is a set of events. |
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| 68 | |
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| 69 | |
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| 70 | 4- VISUALIZATION |
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| 71 | |
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| 72 | The Visualization Manager is set in the main(). |
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| 73 | The initialisation of the drawing is done via the commands |
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| 74 | /vis/... in the macro vis.mac. To get visualisation: |
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| 75 | > /control/execute vis.mac |
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| 76 | |
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| 77 | The detector has a default view which is a longitudinal view of the |
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| 78 | box. |
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| 79 | |
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| 80 | The tracks are drawn at the end of event, and erased at the end of run. |
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| 81 | Optionaly one can choose to draw all particles, only the charged one, |
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| 82 | or none. This command is defined in EventActionMessenger class. |
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| 83 | |
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| 84 | |
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| 85 | 5- HOW TO START ? |
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| 86 | |
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| 87 | - compile and link to generate an executable |
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| 88 | % cd geant4/examples/extended/electromagnetic/TestEm1 |
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| 89 | % gmake |
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| 90 | |
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| 91 | - execute TestEm12 in 'batch' mode from macro files |
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| 92 | % TestEm12 run01.mac |
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| 93 | |
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| 94 | - execute TestEm12 in 'interactive mode' with visualization |
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| 95 | % TestEm12 |
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| 96 | .... |
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| 97 | Idle> type your commands |
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| 98 | .... |
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| 99 | Idle> exit |
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| 100 | |
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| 101 | 6- TRACKING and STEP MAX |
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| 102 | |
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| 103 | Testem12 computes the total energy deposited along the trajectory of |
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| 104 | the incident particle : the so-called longitudinal energy profile, |
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| 105 | or depth dose distribution. |
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| 106 | The energy deposited (edep) is randomly distribued along the step (see |
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| 107 | SteppingAction). |
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| 108 | |
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| 109 | In order to control the accuracy of the deposition, the maximum step size |
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| 110 | of charged particles is computed automatically from the binning of |
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| 111 | histograms 1 and 8 (see HistoManager). |
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| 112 | |
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| 113 | As an example, this limitation is implemented as a 'full' process : |
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| 114 | see StepMax class and its Messenger. The 'StepMax process' is registered |
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| 115 | in the Physics List. |
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| 116 | |
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| 117 | In RunAction::BeginOfRun() the stepMax value is passed from the |
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| 118 | HistoManager to the StepMax process. |
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| 119 | A boolean UI command allows to desactivate this mechanism. |
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| 120 | |
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| 121 | 7- HISTOGRAMS |
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| 122 | |
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| 123 | Testem12 has several predefined 1D histograms : |
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| 124 | |
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| 125 | 1 : energy profile dE/dr (in MeV/mm per event) |
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| 126 | 2 : total energy deposited in the absorber |
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| 127 | 3 : total track length of the primary track |
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| 128 | 4 : step size of the primary track |
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| 129 | 5 : projected range of the primary track |
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| 130 | 6 : total track length of charged secondary tracks |
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| 131 | 7 : step size of charged secondary tracks |
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| 132 | 8 : normalized energy profile d(E/E0)/d(r/r0), where r0 is the range of |
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| 133 | the primary particle of energy E0 |
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| 134 | |
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| 135 | The histograms are managed by the HistoManager class and its Messenger. |
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| 136 | The histos can be individually activated with the command : |
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| 137 | /testem/histo/setHisto id nbBins valMin valMax unit |
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| 138 | where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..) |
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| 139 | |
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| 140 | One can control the name of the histograms file with the command: |
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| 141 | /testem/histo/setFileName name (default testem12) |
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| 142 | |
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| 143 | It is possible to choose the format of the histogram file (hbook, root, XML) |
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| 144 | with the command /testem/histo/setFileType (root by default) |
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| 145 | |
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| 146 | It is also possible to print selected histograms on an ascii file: |
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| 147 | /testem/histo/printHisto id |
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| 148 | All selected histos will be written on a file name.ascii (default testem12) |
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| 149 | |
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| 150 | Note that, by default, histograms are disabled. To activate them, uncomment |
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| 151 | the flag G4ANALYSIS_USE in GNUmakefile. |
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| 152 | |
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| 153 | |
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| 154 | 8- USING HISTOGRAMS |
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| 155 | |
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| 156 | To use histograms, at least one of the AIDA implementations should be |
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| 157 | available. See InstallAida.txt |
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