| 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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