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0001 \page ExampleNeutronSource Example NeutronSource
0002
0003
0004 NeutronSource is an example of neutrons production. It illustrates the cooperative work
0005 of nuclear reactions and radioactive decay processes.
0006 It survey energy deposition and particle's flux.
0007 It uses PhysicsConstructor objects.
0008
0009 ## MATERIALS AND GEOMETRY DEFINITION
0010
0011 The geometry is a cylinder (absorber) of an homogenous material (default : Beryllium oxide).
0012 This absorber is within a container (default : stainless-steel).
0013
0014 Five parameters define the geometry :
0015 - the material of the absorber
0016 - the radius and length of the absorber
0017 - the material of the container
0018 - the thickness of the container
0019
0020 The default geometry is built in DetectorConstruction, but the above
0021 parameters can be changed interactively via commands defined in DetectorMessenger.
0022
0023 The container is surrounded by a World volume (air)
0024
0025 A function, and its associated UI command, allows to build a material
0026 directly from a single isotope.
0027
0028 To be identified by the ThermalScattering module, the elements composing a
0029 material must have a specific name (see G4ParticleHPThermalScatteringNames.cc)
0030 Examples of such materials are build in DetectorConstruction of Hadr04,06,07.
0031
0032 ## PHYSICS LIST
0033
0034 "Full" set of physics processes are registered, but via PhysicsConstructor
0035 objects rather than complete pre-defined G4 physics lists. This alternative
0036 way may give more freedom to register physics.
0037
0038 Physics constructors are either constructors provided in Geant4 (with G4 prefix)
0039 or 'local'. They include : HadronElastic, HadronInelastic, IonsInelastic, GammaNuclear,
0040 RadioactiveDecay and Electomagnetic.
0041 (see geant4/source/physics_lists/constructors)
0042
0043 HadronElasticPhysicsHP include a model for thermalized neutrons, under the control of a command
0044 defined in NeutronHPMesseger.
0045
0046 GammmaNuclearPhysics is a subset of G4BertiniElectroNuclearBuilder.
0047
0048 ElectromagneticPhysics is a simplified version of G4EmStandardPhysics.
0049
0050 RadioactiveDecayPhysics is G4RadioactiveDecayPhysics with SetARM(false).
0051 ARM (for Atomic Relaxation Mode also called Atomic Deexcitation) produce a large number of low energy e-
0052 which slow down the simulation while their contribution is negligible.
0053
0054 In PhysicsList::ConstructProcess() we give an example of how to access hadronic models.
0055
0056 Several hadronic physics options are controlled by environment variables.
0057 To select them, see NeutronSource.cc
0058
0059 ## AN EVENT : THE PRIMARY GENERATOR
0060
0061 The primary kinematic is a single particle uniformly shooted within the absorber.
0062 The type of the particle and its energy are set in PrimaryGeneratorAction (Am241, at rest),
0063 and can be changed via the G4 build-in commands of ParticleGun class
0064 (see the macros provided with this example).
0065
0066 ## PHYSICS
0067
0068 The program computes and plots energy deposited in the interaction volume
0069 (absorber + container) and the flux of particles leaving this volume.
0070 Processes invoked and particles generated during hadronic cascade are listed.
0071
0072 ## HISTOGRAMS
0073
0074 The test contains 13 built-in 1D histograms, which are managed by
0075 G4AnalysisManager and its Messenger. The histos can be individually
0076 activated with the command :
0077 /analysis/h1/set id nbBins valMin valMax unit
0078 where unit is the desired unit for the histo (MeV or keV, etc..)
0079 (see the macros xxxx.mac).
0080 ```
0081 1 "total energy deposit"
0082 2 "dummy"
0083 3 "total kinetic energy flow"
0084 4 "gamma flux (dN/dE) at exit"
0085 5 "e+- flux (dN/dE) at exit"
0086 6 "neutrons flux (dN/dE) at exit"
0087 7 "protons flux (dN/dE) at exit"
0088 8 "deuterons flux (dN/dE) at exit"
0089 9 "alphas flux (dN/dE) at exit"
0090 10 "all others ions flux (dN/dE) at exit"
0091 11 "all others baryons flux (dN/dE) at exit"
0092 12 "all others mesons flux (dN/dE) at exit"
0093 13 "all others leptons flux (dN/dE) at exit"
0094 ```
0095 The histograms are managed by the HistoManager class and its Messenger.
0096 The histos can be individually activated with the command :
0097 ```
0098 /analysis/h1/set id nbBins valMin valMax unit
0099 ```
0100 where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
0101
0102 One can control the name of the histograms file with the command:
0103 ```
0104 /analysis/setFileName name (default NeutronSource)
0105 ```
0106 It is possible to choose the format of the histogram file : root (default),
0107 xml, csv, by using namespace in HistoManager.hh
0108
0109 It is also possible to print selected histograms on an ascii file:
0110 ```
0111 /analysis/h1/setAscii id
0112 ```
0113 All selected histos will be written on a file name.ascii (default NeutronSource)
0114
0115 ## VISUALIZATION
0116
0117 The Visualization Manager is set in the main().
0118 The initialisation of the drawing is done via the commands
0119 /vis/... in the macro vis.mac. To get visualisation:
0120 ```
0121 > /control/execute vis.mac
0122 ```
0123
0124 The tracks are drawn at the end of event, and erased at the end of run.
0125 gamma green
0126 neutron yellow
0127 negative particles (e-, ...) red
0128 positive particles (e+, ions, ...) blue
0129
0130 ## HOW TO START ?
0131
0132 Execute NeutronSource in 'batch' mode from macro files :
0133 ```
0134 % NeutronSource run1.mac
0135 % NeutronSource neutronSource.in > neutronSource.out
0136 ```
0137
0138 Execute NeutronSource in 'interactive mode' with visualization :
0139 ```
0140 % NeutronSource
0141 Idle> control/execute vis.mac
0142 ....
0143 Idle> type your commands
0144 ....
0145 Idle> exit
0146 ```
0147
0148 Macros provided in this example:
0149 - run1.mac: Am-Be system (default configuration)
0150
0151 Macros to be run interactively:
0152 - debug.mac: Am-Be
0153 - vis.mac: To activate visualization
