| 1 | $Id: README,v 1.29 2007/11/12 17:04:55 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 | TestEm3 |
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| 9 | ------- |
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| 10 | |
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| 11 | How to collect energy deposition in a sampling calorimeter. |
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| 12 | How to survey energy flow. |
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| 13 | how to print stopping power. |
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| 14 | |
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| 15 | 1- GEOMETRY DEFINITION |
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| 16 | |
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| 17 | The calorimeter is a box made of a given number of layers. |
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| 18 | A layer consists of a sequence of various absorbers (maximum MaxAbsor=9). |
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| 19 | The layer is replicated. |
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| 20 | |
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| 21 | Parameters defining the calorimeter : |
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| 22 | - the number of layers, |
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| 23 | - the number of absorbers within a layer, |
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| 24 | - the material of the absorbers, |
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| 25 | - the thickness of the absorbers, |
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| 26 | - the transverse size of the calorimeter (the input face is a square). |
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| 27 | |
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| 28 | In addition a transverse uniform magnetic field can be applied. |
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| 29 | |
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| 30 | The default geometry is constructed in DetectorConstruction class, but all |
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| 31 | of the above parameters can be modified interactively via the commands |
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| 32 | defined in the DetectorMessenger class. |
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| 33 | |
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| 34 | |
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| 35 | |<----layer 0---------->|<----layer 1---------->|<----layer 2---------->| |
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| 36 | | | | | |
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| 37 | ========================================================================== |
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| 38 | || | || | || | || |
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| 39 | || | || | || | || |
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| 40 | || abs 1 | abs 2 || abs 1 | abs 2 || abs 1 | abs 2 || |
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| 41 | || | || | || | || |
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| 42 | || | || | || | || |
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| 43 | beam || | || | || | || |
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| 44 | ======> || | || | || | || |
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| 45 | || | || | || | || |
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| 46 | || | || | || | || |
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| 47 | || | || | || | || |
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| 48 | || | || | || | || |
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| 49 | || cell 1 | cell 2|| cell 3 | cell 4|| cell 5 | cell 6|| |
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| 50 | ========================================================================== |
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| 51 | ^ ^ ^ ^ ^ ^ ^ |
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| 52 | pln1 pln2 pln3 pln4 pln5 pln6 pln7 |
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| 53 | |
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| 54 | NB. The number of absorbers and the number of layers can be set to 1. |
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| 55 | In this case we have a unique homogeneous block of matter, which looks like |
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| 56 | a bubble chamber rather than a calorimeter ... |
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| 57 | (see the macro of commands: newgeom.mac) |
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| 58 | |
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| 59 | 2- PHYSICS LISTS |
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| 60 | |
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| 61 | The following options for EM physics are available: |
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| 62 | - "standard" the best standard EM physics (default) |
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| 63 | - "G4standard" recommended standard EM physics for LHC |
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| 64 | - "G4standard_fast" the best CPU performance standard physics for LHC |
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| 65 | - "Livermore" low-energy EM physics using Livermore data |
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| 66 | - "Penelope" low-energy EM physics implementing Penelope models |
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| 67 | |
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| 68 | 3- AN EVENT : THE PRIMARY GENERATOR |
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| 69 | |
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| 70 | The primary kinematic consists of a single particle which hits the calorimeter |
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| 71 | perpendicular to the input face. The type of the particle and its energy are |
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| 72 | set in the PrimaryGeneratorAction class, and can be changed via the |
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| 73 | G4 build-in commands of ParticleGun class (see the macros provided with this |
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| 74 | example). |
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| 75 | |
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| 76 | In addition one can choose randomly the impact point of the incident particle. |
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| 77 | The corresponding interactive command is built in PrimaryGeneratorMessenger. |
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| 78 | |
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| 79 | A RUN is a set of events. |
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| 80 | |
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| 81 | TestEm3 computes the energy deposited per absorber and the energy flow through |
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| 82 | the calorimeter |
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| 83 | |
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| 84 | 4- VISUALIZATION |
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| 85 | |
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| 86 | The Visualization Manager is set in the main(). |
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| 87 | The initialisation of the drawing is done via the commands : |
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| 88 | /vis/... in the macro vis.mac. In interactive session: |
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| 89 | PreInit or Idle > /control/execute vis.mac |
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| 90 | |
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| 91 | The default view is a longitudinal view of the calorimeter. |
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| 92 | |
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| 93 | The tracks are drawn at the end of event, and erased at the end of run. |
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| 94 | Optionaly one can choose to draw all particles, only the charged one, or none. |
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| 95 | This command is defined in EventActionMessenger class. |
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| 96 | |
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| 97 | 5- PHYSICS DEMO |
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| 98 | |
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| 99 | The particle's type and the physic processes which will be available |
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| 100 | in this example are set in PhysicsList class. |
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| 101 | |
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| 102 | In addition a build-in interactive command (/process/inactivate processName) |
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| 103 | allows to activate/inactivate the processes one by one. |
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| 104 | Then one can well visualize the processes one by one, especially |
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| 105 | in the bubble chamber setup with a transverse magnetic field. |
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| 106 | |
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| 107 | As a homework try to visualize a gamma conversion alone, |
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| 108 | or the effect of the multiple scattering. |
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| 109 | |
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| 110 | Notice that one can control the maximum step size in each absorber, via the |
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| 111 | StepMax process and the command /testem/stepMax/absorber |
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| 112 | (see StepMax and PhysicsList classes) |
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| 113 | |
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| 114 | 6- HOW TO START ? |
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| 115 | |
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| 116 | - compile and link to generate an executable |
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| 117 | % cd TestEm3 |
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| 118 | % gmake |
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| 119 | |
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| 120 | - execute TestEm3 in 'batch' mode from macro files |
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| 121 | % TestEm3 run01.mac |
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| 122 | |
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| 123 | - execute TestEm3 in 'interactive mode' with visualization |
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| 124 | % TestEm3 |
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| 125 | .... |
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| 126 | Idle> type your commands. For instance: |
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| 127 | Idle> /control/execute run01.mac |
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| 128 | .... |
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| 129 | Idle> exit |
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| 130 | |
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| 131 | 7- HISTOGRAMS |
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| 132 | |
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| 133 | Testem3 can produce histograms : |
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| 134 | histo 1 : energy deposit in absorber 1 |
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| 135 | histo 2 : energy deposit in absorber 2 |
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| 136 | ...etc........... |
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| 137 | |
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| 138 | One can control the binning of the histo with the command: |
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| 139 | /testem/histo/setHisto idAbsor nbin Emin Emax unit |
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| 140 | ...etc........... |
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| 141 | where unit is the desired energy unit for that histo (see TestEm3.in). |
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| 142 | |
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| 143 | histo 11 : longitudinal profile of energy deposit in absorber 1 (MeV/event) |
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| 144 | histo 12 : longitudinal profile of energy deposit in absorber 2 (MeV/event) |
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| 145 | ...etc........... |
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| 146 | |
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| 147 | histo 21 : energy flow (MeV/event) |
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| 148 | histo 22 : lateral energy leak (MeV/event) |
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| 149 | |
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| 150 | One can control the name of the histograms file with the command: |
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| 151 | /testem/histo/setFileName name (default testem3.hbook) |
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| 152 | |
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| 153 | NB. Numbering scheme for histograms: |
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| 154 | layer : from 1 to NbOfLayers (inclued) |
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| 155 | absorbers : from 1 to NbOfAbsor (inclued) |
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| 156 | planes : from 1 to NbOfLayers*NbOfAbsor + 1 (inclued) |
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| 157 | |
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| 158 | It is also possible to print selected histograms on an ascii file: |
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| 159 | /testem/histo/printHisto id |
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| 160 | All selected histos will be written on a file name.ascii (default testem3) |
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| 161 | |
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| 162 | Note that, by default, histograms are disabled. To activate them, uncomment |
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| 163 | the flag G4ANALYSIS_USE in GNUmakefile. |
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| 164 | |
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| 165 | Before compilation of the example it is optimal to clean up old files: |
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| 166 | gmake histclean |
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| 167 | gmake |
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| 168 | |
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| 169 | |
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| 170 | 8- USING HISTOGRAMS |
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| 171 | |
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| 172 | To use histograms, at least one of the AIDA implementations should be |
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| 173 | available (see http://aida.freehep.org). |
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| 174 | |
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| 175 | 8a - PI |
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| 176 | |
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| 177 | A package including AIDA and extended interfaces also using Python is PI, |
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| 178 | available from: http://cern.ch/pi |
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| 179 | |
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| 180 | Once installed PI or PI-Lite in a specified local area $MYPY, it is required |
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| 181 | to add the installation path to $PATH, i.e. for example, for release 1.2.1 of |
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| 182 | PI: |
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| 183 | setenv PATH ${PATH}:$MYPI/1.2.1/app/releases/PI/PI_1_2_1/rh73_gcc32/bin |
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| 184 | |
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| 185 | CERN users can use the PATH to the LCG area on AFS. |
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| 186 | Before running the example the command should be issued: |
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| 187 | eval `aida-config --runtime csh` |
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| 188 | |
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| 189 | 8b - OpenScientist |
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| 190 | |
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| 191 | OpenScientist is available at http://OpenScientist.lal.in2p3.fr. |
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| 192 | |
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| 193 | You have to "setup" the OpenScientist AIDA implementation before compiling |
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| 194 | (then with G4ANALYSIS_USE set) and running your Geant4 application. |
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| 195 | |
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| 196 | On UNIX you setup, with a csh flavoured shell : |
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| 197 | csh> source <<OpenScientist install path>/aida-setup.csh |
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| 198 | or with a sh flavoured shell : |
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| 199 | sh> . <<OpenScientist install path>/aida-setup.sh |
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| 200 | On Windows : |
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| 201 | DOS> call <<OpenScientist install path>/aida-setup.bat |
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| 202 | |
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| 203 | You can use various file formats for writing (AIDA-XML, hbook, root). |
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| 204 | These formats are readable by the Lab onx interactive program |
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| 205 | or the OpenPAW application. See the web pages. |
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| 206 | |
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| 207 | |
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| 208 | With OpenPAW, on a run.hbook file, one can view the histograms |
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| 209 | with something like : |
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| 210 | OS> opaw |
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| 211 | opaw> h/file 1 run.hbook ( or opaw> h/file 1 run.aida or run.root) |
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| 212 | opaw> zone 2 2 |
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| 213 | opaw> h/plot 1 |
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| 214 | opaw> h/plot 2 |
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