Geant4 Cross Reference |
1 ---------------------------------------------- 1 ------------------------------------------------------------------- 2 2 3 ========================================= 3 ========================================================= 4 Geant4 - an Object-Oriented Toolkit for S 4 Geant4 - an Object-Oriented Toolkit for Simulation in HEP 5 ========================================= 5 ========================================================= 6 6 7 TestEm18 7 TestEm18 8 -------- 8 -------- 9 This example allows to study the various c 9 This example allows to study the various contributions of the energy lost 10 by a charged particle in a single layer of 10 by a charged particle in a single layer of an homogeneous material. 11 See any textbook of interactions of charge 11 See any textbook of interactions of charged particles with matter, in particular : 12 1- geant4.web.cern.ch --> UserSupport -- 12 1- geant4.web.cern.ch --> UserSupport --> Physics Reference Manual 13 2- lappweb.in2p3.fr/~maire/tutorials/ind 13 2- lappweb.in2p3.fr/~maire/tutorials/index.html 14 14 15 1- GEOMETRY DEFINITION 15 1- GEOMETRY DEFINITION 16 16 17 It is a simple cubic box of homogeneous ma 17 It is a simple cubic box of homogeneous material. 18 Two parameters define the geometry : 18 Two parameters define the geometry : 19 - the material of the box, 19 - the material of the box, 20 - the thickness of the box. 20 - the thickness of the box. 21 21 22 The default geometry (1 cm of water) is co 22 The default geometry (1 cm of water) is constructed in DetectorConstruction, 23 but the above parameters can be changed in 23 but the above parameters can be changed interactively via the commands 24 defined in DetectorMessenger. 24 defined in DetectorMessenger. 25 25 26 2- PHYSICS 26 2- PHYSICS 27 27 28 The physics list contains the 'standard' e 28 The physics list contains the 'standard' electromagnetic processes. 29 However the MultipleScattering is not regi 29 However the MultipleScattering is not registered, in order to focuse on 30 fluctuations of to energy loss alone. 30 fluctuations of to energy loss alone. 31 31 32 3- BEAM 32 3- BEAM 33 33 34 The primary kinematic is a single particle 34 The primary kinematic is a single particle starting at the edge 35 of the box. The type of the particle and i 35 of the box. The type of the particle and its energy are set in 36 PrimaryGeneratorAction (e- 10 MeV), and ca 36 PrimaryGeneratorAction (e- 10 MeV), and can be changed via the G4 37 build-in commands of ParticleGun class. 37 build-in commands of ParticleGun class. 38 38 39 4- RUN 39 4- RUN 40 40 41 During the tracking of the incident partic 41 During the tracking of the incident particle, by default, the secondary 42 particles are immediately killed, after th 42 particles are immediately killed, after that their energy has been registered 43 (see SteppingAction and StackingAction). 43 (see SteppingAction and StackingAction). 44 Therefore, we study here the various compo 44 Therefore, we study here the various components of the total energy lost 45 by the incident particle, not the energy d 45 by the incident particle, not the energy deposited in a layer of finite 46 thickness. 46 thickness. 47 With the option /testEm/trackSecondaries o 47 With the option /testEm/trackSecondaries one can compute and plot the energy 48 deposited in the layer. See edep.mac 48 deposited in the layer. See edep.mac 49 49 50 At EndOfRun, the above results are compare 50 At EndOfRun, the above results are compared with 'reference' values, 51 i.e. the input data read from EnergyLoss a 51 i.e. the input data read from EnergyLoss and Range tables. 52 See reference 2 : Energy-Range relation, s 52 See reference 2 : Energy-Range relation, slide 4. 53 53 54 5- HISTOGRAMS 54 5- HISTOGRAMS 55 55 56 The test contains 13 built-in 1D histogram 56 The test contains 13 built-in 1D histograms, which are managed by 57 G4AnalysisManager and its Messenger. 57 G4AnalysisManager and its Messenger. 58 58 59 1 step size of primary track 59 1 step size of primary track 60 2 energy continuously deposited al 60 2 energy continuously deposited along primary track 61 3 energy transfered to secondaries 61 3 energy transfered to secondaries by ionisation 62 4 energy transfered to secondaries 62 4 energy transfered to secondaries by Bremsstrahlung 63 5 energy transfered to secondaries 63 5 energy transfered to secondaries by (e+,e-) production 64 6 total energy transfered to secon 64 6 total energy transfered to secondaries 65 7 total energy lost by primary tra 65 7 total energy lost by primary track 66 8 total energy lost by primary tra 66 8 total energy lost by primary track from energy balance 67 9 energy continuously deposited al 67 9 energy continuously deposited along secondary tracks 68 10 total energy deposited 68 10 total energy deposited 69 11 energy spectrum of gamma 69 11 energy spectrum of gamma 70 12 energy spectrum of e- 70 12 energy spectrum of e- 71 13 energy spectrum of e+ 71 13 energy spectrum of e+ 72 72 73 The histograms are defined in HistoManager 73 The histograms are defined in HistoManager. 74 74 75 The histos can be activated individually w 75 The histos can be activated individually with the command : 76 /analysis/h1/set id nbBins valMin valMax u 76 /analysis/h1/set id nbBins valMin valMax unit 77 where 'unit' is the desired unit for the h 77 where 'unit' is the desired unit for the histo (MeV or KeV, cm or mm, etc..) 78 78 79 One can control the name of the histograms 79 One can control the name of the histograms file with the command: 80 /analysis/setFileName name (default test 80 /analysis/setFileName name (default testem18) 81 81 82 It is possible to choose the format of the 82 It is possible to choose the format of the histogram file : root (default), 83 xml, csv, by using namespace in HistoManag 83 xml, csv, by using namespace in HistoManager.hh 84 For convenience, few simple Root macros ar 84 For convenience, few simple Root macros are provided : plotHisto.C pixe.C 85 It is also possible to print selected hist 85 It is also possible to print selected histograms on an ascii file: 86 /analysis/h1/setAscii id 86 /analysis/h1/setAscii id 87 All selected histos will be written on a f 87 All selected histos will be written on a file name.ascii (default testem18) 88 88 89 6- VISUALIZATION 89 6- VISUALIZATION 90 90 91 The Visualization Manager is set in the ma 91 The Visualization Manager is set in the main(). 92 The initialisation of the drawing is done 92 The initialisation of the drawing is done via the commands 93 /vis/... in the macro vis.mac. To get visu 93 /vis/... in the macro vis.mac. To get visualisation: 94 > /control/execute vis.mac 94 > /control/execute vis.mac 95 95 96 The detector has a default view which is a 96 The detector has a default view which is a longitudinal view of the box. 97 The tracks are drawn at the end of event, 97 The tracks are drawn at the end of event, and erased at the end of run. 98 98 99 7- HOW TO START ? 99 7- HOW TO START ? 100 100 101 execute TestEm18 in 'batch' mode from macr 101 execute TestEm18 in 'batch' mode from macro files : 102 % TestEm18 electron.mac 102 % TestEm18 electron.mac 103 103 104 execute TestEm18 in 'interactive mode' wit 104 execute TestEm18 in 'interactive mode' with visualization : 105 % TestEm18 105 % TestEm18 106 Idle> control/execute vis.mac 106 Idle> control/execute vis.mac 107 .... 107 .... 108 Idle> type your commands 108 Idle> type your commands 109 .... 109 .... 110 Idle> exit 110 Idle> exit 111 111 112 Macros provided in this example: 112 Macros provided in this example: 113 - csda.mac: test independance of user step m 113 - csda.mac: test independance of user step max 114 - edep.mac: track secondary particles and pl 114 - edep.mac: track secondary particles and plot energy deposited 115 - electron.mac: e- (10 MeV) on 1 cm of water 115 - electron.mac: e- (10 MeV) on 1 cm of water 116 - ion.mac: ion C12 (4 GeV) on 1 cm of water 116 - ion.mac: ion C12 (4 GeV) on 1 cm of water 117 - muon.mac: mu+ (1 TeV) on 1 m of water 117 - muon.mac: mu+ (1 TeV) on 1 m of water 118 - pixe.mac: proton (20 MeV) on 50 um of gold 118 - pixe.mac: proton (20 MeV) on 50 um of gold. Plot gamma pixe 119 - proton.mac: proton (1 GeV) on 10 cm of wat 119 - proton.mac: proton (1 GeV) on 10 cm of water 120 - plotHisto.C, pixe.C: Root macros 120 - plotHisto.C, pixe.C: Root macros 121 121 122 Macros to be run interactively: 122 Macros to be run interactively: 123 - vis.mac: To activate visualization 123 - vis.mac: To activate visualization