| 1 | $Id: README,v 1.22 2009/11/21 22:02:51 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 | TestEm7
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| 9 | -------
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| 10 |
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| 11 | How to produce a Bragg curve in a water phantom.
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| 12 | How to compute the dose in small 'test volumes' called tallies.
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| 13 | How to define a maximum step size.
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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 block of a homogenous material,
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| 18 | placed in a world.
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| 19 |
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| 20 | Three parameters define the geometry :
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| 21 | - the material of the box,
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| 22 | - the thickness of the box (sizeX),
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| 23 | - the tranverse dimension of the box (sizeYZ).
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| 24 |
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| 25 | The default is 20 cm of water.
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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 of the above parameters can be changed interactively via
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| 31 | the commands defined in the DetectorMessenger class.
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| 32 |
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| 33 | The size, matter, positions of several test-volumes (tallies) can be
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| 34 | defined via UI commands : /testem/det/tally...
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| 35 |
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| 36 | 2- PHYSICS LIST
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| 37 |
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| 38 | Physics lists can be local (eg. in this example) or from G4 kernel
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| 39 | physics_lists subdirectory.
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| 40 |
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| 41 | Local physics lists:
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| 42 | - "local" standard EM physics with current 'best' options setting.
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| 43 | these options are explicited in PhysListEmStandard
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| 44 | - "standardSS" standard EM physics with single Coulomb scattering
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| 45 | instead of multiple scattering;
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| 46 | - "standardNR" standard EM physics with single Coulomb scattering
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| 47 | process G4ScreenedNuclearRecoil instead of the
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| 48 | multiple scattering for ions with energy less than
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| 49 | 100 MeV/nucleon; the new process was developed
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| 50 | by M.H. Mendenhall and R.A. Weller from Vanderbuilt
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| 51 | University and published in NIM B 277 (2005) 420.
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| 52 | In later Geant4 releases the process will be a part
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| 53 | of Geant4 source, currently it is released together
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| 54 | with its mathematical tool c2_functions in current
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| 55 |
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| 56 |
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| 57 | From geant4/source/physics_lists/builders:
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| 58 | - "emstandard_opt0" recommended standard EM physics for LHC
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| 59 | - "emstandard_opt1" best CPU performance standard physics for LHC
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| 60 | - "emstandard_opt2"
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| 61 | - "emstandard_opt3" best current advanced EM options.
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| 62 | analog to "local" above
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| 63 | - "emlivermore" low-energy EM physics using Livermore data
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| 64 | - "empenelope" low-energy EM physics implementing Penelope models
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| 65 |
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| 66 | Optional components can be added:
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| 67 | - "elastic" elastic scattering of hadrons
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| 68 | - "HElastic"
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| 69 | - "QElastic"
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| 70 | - "binary" QBBC configuration of hadron inelastic models
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| 71 | - "binary_ion" Binary ion inelastic models
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| 72 |
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| 73 | Physics lists and options can be (re)set with UI commands
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| 74 |
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| 75 | Please, notice that options set through G4EmProcessOPtions are global, eg
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| 76 | for all particle types. In G4 builders, it is shown how to set options per
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| 77 | particle type.
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| 78 |
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| 79 | 3- AN EVENT : THE PRIMARY GENERATOR
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| 80 |
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| 81 | The primary kinematic consists of a single particle which hits the
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| 82 | block perpendicular to the input face. The type of the particle
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| 83 | and its energy are set in the PrimaryGeneratorAction class, and can
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| 84 | changed via the G4 build-in commands of ParticleGun class (see
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| 85 | the macros provided with this example).
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| 86 | The default is proton 160 MeV
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| 87 |
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| 88 | In addition one can define randomly the impact point of the incident
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| 89 | particle. The corresponding interactive command is built in
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| 90 | PrimaryGeneratorMessenger class.
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| 91 |
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| 92 | A RUN is a set of events.
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| 93 |
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| 94 |
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| 95 | 4- DOSE IN 'TEST-VOLUMES'
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| 96 |
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| 97 | The energy deposited in the test-volumes (tallies) defined in
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| 98 | DetectorConstruction are printed at EndOfRun, both in MeV and gray.
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| 99 |
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| 100 | 5- VISUALIZATION
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| 101 |
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| 102 | The Visualization Manager is set in the main().
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| 103 | The initialisation of the drawing is done via the command
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| 104 | > /control/execute vis.mac
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| 105 |
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| 106 | The detector has a default view which is a longitudinal view of the box.
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| 107 |
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| 108 | The tracks are drawn at the end of event, and erased at the end of run.
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| 109 | Optionaly one can choose to draw all particles, only the charged one,
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| 110 | or none. This command is defined in EventActionMessenger class.
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| 111 |
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| 112 |
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| 113 | 6- HOW TO START ?
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| 114 |
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| 115 | - compile and link to generate an executable
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| 116 | % cd geant4/examples/extended/electromagnetic/TestEm7
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| 117 | % gmake
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| 118 |
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| 119 | - execute Test in 'batch' mode from macro files
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| 120 | % TestEm7 proton.mac
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| 121 |
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| 122 | - execute Test in 'interactive mode' with visualization
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| 123 | % TestEm7
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| 124 | ....
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| 125 | Idle> type your commands
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| 126 | ....
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| 127 | Idle> exit
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| 128 |
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| 129 |
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| 130 | 7- HISTOGRAM OF THE BRAGG PEAK
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| 131 |
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| 132 | Testem7 computes the total energy deposited along the trajectory of
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| 133 | the incident particle : the so-called Bragg peak.
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| 134 |
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| 135 | In order to control the accuracy of the deposition, the user can limit
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| 136 | the maximum allowed for the step size of charged particles.
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| 137 | (command /testem/stepMax )
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| 138 |
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| 139 | The result is a 1D histogram, which is the total energy deposited
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| 140 | along the trajectory of the incident particle.
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| 141 |
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| 142 | The bin size is egal to stepMax. The number of bins is determined by
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| 143 | the thickness of the absorber (with a minimum of 100 bins).
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| 144 | The total energy deposited is plotted in MeV/mm per incident particle.
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| 145 |
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| 146 | The next histogram alowing to have a zoom around the Bragg peak. Its binning
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| 147 | should be defined via UI command:
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| 148 | /testem/histo/setHisto 1 nbins xmin xmax
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| 149 |
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| 150 | The last histogram shows the projectile range. Its binning should be defined
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| 151 | similary by the UI command:
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| 152 | /testem/histo/setHisto 2 nbins xmin xmax
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| 153 |
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| 154 | 8- USING HISTOGRAMS
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| 155 |
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| 156 | By default the histograms are not activated. To activate histograms
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| 157 | the environment variable G4ANALYSIS_USE should be defined. For instance
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| 158 | uncomment the flag G4ANALYSIS_USE in GNUmakefile.
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| 159 |
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| 160 | To use histograms, at least one of the AIDA implementations should be
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| 161 | available. See InstallAida.txt
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| 162 |
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| 163 | Before compilation of the example it is optimal to clean up old files:
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| 164 | gmake histclean
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| 165 | gmake
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| 166 |
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| 167 | It is possible to choose the format of the histogram file (hbook, root, XML):
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| 168 | /testem/histo/setHistoType root
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| 169 |
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| 170 | The default name "testem7" can be changed:
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| 171 | /testem/histo/setHistoName myname
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