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Survey energy deposition and particle's flux from an hadronic cascade, including radioactive decays. The main purpose of the example is to plot evolution of each metastable isomer as a function of time, taking into account the time of exposure in the beam. Also plot the activity of emerging particles. Use PhysicsConstructor objects rather than predefined G4 PhysicsLists.
The "absorber" is a box made of a given material.
Three parameters define the absorber :
The volume "World" contains the "absorber".
A function, and its associated UI command, allows to build a material directly from a single isotope.
To be identified by the ThermalScattering module, the elements composing a material must have a specific name (see G4ParticleHPThermalScatteringNames.cc) Examples of such materials are build in DetectorConstruction::DefineMaterials().
The physics list contains a "full" set of physics processes. It is defined in the PhysicsList class as a Geant4 modular physics list with registered physics constructors (builders).
Physics constructors are either constructors provided in Geant4 (with G4 prefix) or 'local'. They include : HadronElastic, HadronInelastic, IonsInelastic, GammaNuclear, RadioactiveDecay and Electomagnetic. (see geant4/source/physics_lists/constructors)
HadronElasticPhysicsHP include a model for thermalized neutrons, under the control of a command defined in NeutronHPMesseger.
GammmaNuclearPhysics is a subset of G4BertiniElectroNuclearBuilder.
ElectromagneticPhysics is a simplified version of G4EmStandardPhysics.
Several hadronic physics options are controlled by environment variables. To select them, see Activation.cc
The primary kinematic is a single particle which hits the absorber perpendicular to the input face. The type of particle and its energy are set in the PrimaryGeneratorAction class, and can be changed via the G4 build-in commands of G4ParticleGun class (see the macros provided with this example).
One can control the transverse size of the beam. The command
/testhadr/gun/beamSize
is built in PrimaryGeneratorMessenger class.
The time of exposure in the beam may be finite. It is controled by the command
/testhadr/gun/beamTime.
Then the time zero of each event is randomly chosen within this interval.
The program computes and plots energy deposited in the interaction volume (absorber), energy spectrum and activity of particles leaving the absorber, and evolution of population of metastable isomers within the absorber (see below : histograms). Processes invoked and particles generated during interactions are listed.
The test contains 43 built-in 1D histograms, which are managed by G4AnalysisManager and its Messenger. The histos can be individually activated with the command :
/analysis/h1/set id nbBins valMin valMax unit
where unit is the desired unit for the histo (MeV or keV, etc..) (see the macros xxxx.mac).
1 "total energy deposit"
2 "Edep (MeV/mm) profile along beam direction"
3 "total kinetic energy emerging"
4 "energy spectrum of emerging gamma"
5 "energy spectrum of emerging e+-"
6 "energy spectrum of emerging neutrons"
7 "energy spectrum of emerging protons"
8 "energy spectrum of emerging deuterons"
9 "energy spectrum of emerging alphas"
10 "energy spectrum of all others emerging ions"
11 "energy spectrum of all others emerging baryons"
12 "energy spectrum of all others emerging mesons"
13 "energy spectrum of all others emerging leptons (neutrinos)"
14 "dN/dt (becquerel) of emerging gamma"
15 "dN/dt (becquerel) of emerging e+-"
16 "dN/dt (becquerel) of emerging neutrons"
17 "dN/dt (becquerel) of emerging protons"
18 "dN/dt (becquerel) of emerging deuterons"
19 "dN/dt (becquerel) of emerging alphas"
20 "dN/dt (becquerel) of all others emerging ions"
21 "dN/dt (becquerel) of all others emerging baryons"
22 "dN/dt (becquerel) of all others emerging mesons"
23 "dN/dt (becquerel) of all others emerging leptons (neutrinos)"
Histograms 24 to 43 are assigned to population of metastable isomer. Here, ´metastable' means time life > 0.
The type and number of isomers created in a run cannot be predicted in advance. Therefore the assignation : isomer <--> histo_Id is done on fly and printed at end of run. A lock mechanism is necessary in MT mode; see Run.cc
Activation and binning control of histograms is done with the usual command
/analysis/h1/set
One can control the name of the histograms file with the command:
/analysis/setFileName name (default Activation)
It is possible to choose the format of the histogram file : root (default), xml, csv, by using namespace in HistoManager.hh
It is also possible to print selected histograms on an ascii file:
/analysis/h1/setAscii id
All selected histos will be written on a file name.ascii (default Activation)
The Visualization Manager is set in the main(). The initialisation of the drawing is done via the commands /vis/... in the macro vis.mac. To get visualisation:
> /control/execute vis.mac
The tracks are drawn at the end of event, and erased at the end of run.
gamma green
neutron yellow negative particles (e-, ...) red positive particles (e+, ions, ...) blue
Execute Activation in 'batch' mode from macro files :
% ./Activation run.mac
Execute Activation in 'interactive mode' with visualization :
% ./Activation Idle> control/execute debug.mac .... Idle> type your commands .... Idle> exit
Macros provided in this example:
Macros to be run interactively:
1.9.8