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0001
0002 =========================================================
0003 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
0004 =========================================================
0005
0006 Activation
0007 ----------
0008
0009 Survey energy deposition and particle's flux from an hadronic cascade,
0010 including radioactive decays.
0011 The main purpose of the example is to plot evolution of each metastable isomer
0012 as a function of time, taking into account the time of exposure in the beam.
0013 Also plot the activity of emerging particles.
0014 Use PhysicsConstructor objects rather than predefined G4 PhysicsLists.
0015
0016 1- MATERIALS AND GEOMETRY DEFINITION
0017
0018 The "absorber" is a box made of a given material.
0019
0020 Three parameters define the absorber :
0021 - the material of the absorber
0022 - the thickness of an absorber
0023 - the transverse size of the absorber (the input face is a square)
0024
0025 The volume "World" contains the "absorber".
0026
0027 A function, and its associated UI command, allows to build a material
0028 directly from a single isotope.
0029
0030 To be identified by the ThermalScattering module, the elements composing a
0031 material must have a specific name (see G4ParticleHPThermalScatteringNames.cc)
0032 Examples of such materials are build in DetectorConstruction::DefineMaterials().
0033
0034 2- PHYSICS LIST
0035
0036 The physics list contains a "full" set of physics processes. It is defined in
0037 the PhysicsList class as a Geant4 modular physics list with registered physics
0038 constructors (builders).
0039
0040 Physics constructors are either constructors provided in Geant4 (with G4 prefix)
0041 or 'local'. They include : HadronElastic, HadronInelastic, IonsInelastic, GammaNuclear,
0042 RadioactiveDecay and Electomagnetic.
0043 (see geant4/source/physics_lists/constructors)
0044
0045 HadronElasticPhysicsHP include a model for thermalized neutrons, under the control of a command
0046 defined in NeutronHPMesseger.
0047
0048 GammmaNuclearPhysics is a subset of G4BertiniElectroNuclearBuilder.
0049
0050 ElectromagneticPhysics is a simplified version of G4EmStandardPhysics.
0051
0052 Several hadronic physics options are controlled by environment variables.
0053 To select them, see Activation.cc
0054
0055 3- AN EVENT : THE PRIMARY GENERATOR
0056
0057 The primary kinematic is a single particle which hits the absorber
0058 perpendicular to the input face. The type of particle and its energy are
0059 set in the PrimaryGeneratorAction class, and can be changed via the G4
0060 build-in commands of G4ParticleGun class
0061 (see the macros provided with this example).
0062
0063 One can control the transverse size of the beam.
0064 The command /testhadr/gun/beamSize is built in PrimaryGeneratorMessenger class.
0065
0066 The time of exposure in the beam may be finite. It is controled by the command
0067 /testhadr/gun/beamTime.
0068 Then the time zero of each event is randomly chosen within this interval.
0069
0070 4- PHYSICS
0071
0072 The program computes and plots energy deposited in the interaction volume
0073 (absorber), energy spectrum and activity of particles leaving the absorber,
0074 and evolution of population of metastable isomers within the absorber
0075 (see below : histograms).
0076 Processes invoked and particles generated during interactions are listed.
0077
0078 5- HISTOGRAMS
0079
0080 The test contains 43 built-in 1D histograms, which are managed by
0081 G4AnalysisManager and its Messenger. The histos can be individually
0082 activated with the command :
0083 /analysis/h1/set id nbBins valMin valMax unit
0084 where unit is the desired unit for the histo (MeV or keV, etc..)
0085 (see the macros xxxx.mac).
0086
0087 1 "total energy deposit"
0088 2 "Edep (MeV/mm) profile along beam direction"
0089 3 "total kinetic energy emerging"
0090 4 "energy spectrum of emerging gamma"
0091 5 "energy spectrum of emerging e+-"
0092 6 "energy spectrum of emerging neutrons"
0093 7 "energy spectrum of emerging protons"
0094 8 "energy spectrum of emerging deuterons"
0095 9 "energy spectrum of emerging alphas"
0096 10 "energy spectrum of all others emerging ions"
0097 11 "energy spectrum of all others emerging baryons"
0098 12 "energy spectrum of all others emerging mesons"
0099 13 "energy spectrum of all others emerging leptons (neutrinos)"
0100 14 "dN/dt (becquerel) of emerging gamma"
0101 15 "dN/dt (becquerel) of emerging e+-"
0102 16 "dN/dt (becquerel) of emerging neutrons"
0103 17 "dN/dt (becquerel) of emerging protons"
0104 18 "dN/dt (becquerel) of emerging deuterons"
0105 19 "dN/dt (becquerel) of emerging alphas"
0106 20 "dN/dt (becquerel) of all others emerging ions"
0107 21 "dN/dt (becquerel) of all others emerging baryons"
0108 22 "dN/dt (becquerel) of all others emerging mesons"
0109 23 "dN/dt (becquerel) of all others emerging leptons (neutrinos)"
0110
0111 Histograms 24 to 43 are assigned to population of metastable isomer.
0112 Here, ´metastable' means time life > 0.
0113
0114 The type and number of isomers created in a run cannot be predicted in advance.
0115 Therefore the assignation : isomer <--> histo_Id is done on fly
0116 and printed at end of run. A lock mechanism is necessary in MT mode; see Run.cc
0117
0118 Activation and binning control of histograms is done with the usual command
0119 /analysis/h1/set
0120
0121 One can control the name of the histograms file with the command:
0122 /analysis/setFileName name (default Activation)
0123
0124 It is possible to choose the format of the histogram file : root (default),
0125 xml, csv, by using namespace in HistoManager.hh
0126
0127 It is also possible to print selected histograms on an ascii file:
0128 /analysis/h1/setAscii id
0129 All selected histos will be written on a file name.ascii (default Activation)
0130
0131 6- VISUALIZATION
0132
0133 The Visualization Manager is set in the main().
0134 The initialisation of the drawing is done via the commands
0135 /vis/... in the macro vis.mac. To get visualisation:
0136 > /control/execute vis.mac
0137
0138 The tracks are drawn at the end of event, and erased at the end of run.
0139 gamma green
0140 neutron yellow
0141 negative particles (e-, ...) red
0142 positive particles (e+, ions, ...) blue
0143
0144 7- HOW TO START ?
0145
0146 Execute Activation in 'batch' mode from macro files :
0147 % ./Activation run.mac
0148 % ./Activation Activation.in > Activation.out
0149
0150 Execute Activation in 'interactive mode' with visualization :
0151 % ./Activation
0152 Idle> control/execute debug.mac
0153 ....
0154 Idle> type your commands
0155 ....
0156 Idle> exit
0157
0158 Macros provided in this example:
0159 - Bi209.mac: neutron (25 meV) on 10 cm of Bi209
0160 - Co60.mac: neutron (25 meV) on 1 cm of Cobalt.
0161 - run.mac: simplified Co60.mac (no beam time, no histograms)
0162
0163 Macros to be run interactively:
0164 - vis.mac: To activate visualization
0165 - debug.mac: 1 neutron (25 meV) on Cobalt. Visualization and tracking/verbose
0166
