[1342] | 1 | $Id: README,v 1.23 2010/09/17 18:45:43 maire Exp $ |
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[807] | 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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[1337] | 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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[807] | 55 | |
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| 56 | |
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[1337] | 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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[807] | 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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[1337] | 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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[807] | 99 | |
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[1337] | 100 | 5- VISUALIZATION |
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[807] | 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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[1337] | 113 | 6- HOW TO START ? |
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[807] | 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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[1337] | 130 | 7- HISTOGRAM OF THE BRAGG PEAK |
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[807] | 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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[1337] | 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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[807] | 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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[1342] | 146 | The next histogram allows to have a zoom around the Bragg peak. Its bining |
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[1337] | 147 | should be defined via UI command: |
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[1342] | 148 | /testem/histo/setHisto 2 nbins xmin xmax unit |
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[807] | 149 | |
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[1342] | 150 | The last histogram shows the projectile range. Its bining should be defined |
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[1337] | 151 | similary by the UI command: |
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[1342] | 152 | /testem/histo/setHisto 3 nbins xmin xmax unit |
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[1337] | 153 | |
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| 154 | 8- USING HISTOGRAMS |
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[807] | 155 | |
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[1337] | 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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[807] | 162 | |
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[1337] | 163 | Before compilation of the example it is optimal to clean up old files: |
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[807] | 164 | gmake histclean |
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| 165 | gmake |
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| 166 | |
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[1342] | 167 | One can choose the format of the histogram file (hbook, root, XML): |
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| 168 | /testem/histo/setFileType root |
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[807] | 169 | |
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[1337] | 170 | The default name "testem7" can be changed: |
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[1342] | 171 | /testem/histo/setFileName myname |
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