Gabriele Cosmo
120 lines
3.9 KiB
Markdown
120 lines
3.9 KiB
Markdown
\page ExampleTestEm17 Example TestEm17
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This example is intended to check implementation of the processes
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of muon interactions: ionization, direct (e+,e-) production, mu+mu-
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pair production, bremsstrahlung, and mu-nuclear interaction.
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It allows to compute differential cross sections (as function of the
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energy transfered to secondaries), total cross sections, and to compare
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with analytic calculations.
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## GEOMETRY DEFINITION
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It is a single box of homogeneous medium.
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Two parameters define the geometry :
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- the material of the box,
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- the (full) size of the box.
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The default geometry (1 m of Iron) is constructed in
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DetectorConstruction, but the above parameters can be changed
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interactively via the commands defined in DetectorMessenger.
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## PHYSICS LIST
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The Physics List of the example uses the main physics constructor
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(builder) called "local", which includes only muon, pion, and proton
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processes under study. As an alternative standard "emstandard_opt0"
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and "emstandard_opt4" constructors may be used.
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Default energy range for EM processes in this example
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is from 100*eV to 1000*PeV.
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Optionally "muNucl" builder, MuNuclearBuilder, may be added activating muon-nuclear
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inelastic interaction.
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## AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic consists of a single particle starting at the edge
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of the box. The type of the particle and its energy are set in
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PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4
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build-in commands of ParticleGun class (see the macros provided with
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this example).
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## PHYSICS
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The incident particle is a muon. During the tracking, secondary
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particles are killed.
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The number of interactions are plotted as a function of the energy
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transfered to the secondaries.
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The total number of interactions is recorded, and the total cross section
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computed from this.
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At RunAction::EndOfRun(..), the above results are compared with analytical
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calculations. The functions computing the theoretical cross sections have been
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provided by the G4 MEPhI group, and implemented in MuCrossSections class.
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## HISTOGRAMS
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The test contains 8 built-in 1D histograms, which are managed by the
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HistoManager class and its messenger, HistoMessenger.
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- 1 Relative muon transferred energy distribution
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(log10(eps/Emu kin) for knock-on electrons (ionization)
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- 2 ... direct (e+,e-) pair production by muons
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- 3 ... bremsstrahlung by muons
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- 4 ... nuclear interaction by muons
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- 5 ... ionistion for hadrons
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- 6 ... (e+,e-) pair production by hadrons
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- 7 ... bremsstrahlung by hadrons
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- 8 ... direct mu+,mu- pair production by muons
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The histos can be activated individually with the command :
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```
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/testem/histo/setHisto id nbBins valMin valMax
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```
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min and max values of log10(eps/Emu kin).
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At RunAction::EndOfRunAction() the corresponding histos for analytic calculations are
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automatically created and filled (histo 11 to 14, and 18).
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One can control the name and the type of the histograms file with
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the command:
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```
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/testem/histo/setFileName name (default testem17)
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```
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It is possible to choose the format of the histogram file :
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root (default), xml, csv by changing the default file type in HistoManager.cc.
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## VISUALIZATION
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The Visualization Manager is set in the main().
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The initialisation of the drawing is done via the commands
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/vis/... in the macro vis.mac. To get visualisation:
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```
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> /control/execute vis.mac
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```
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The detector has a default view which is a longitudinal view of the
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box.
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The tracks are drawn at the end of event, and erased at the end of run.
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## HOW TO START ?
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- Execute TestEm17 in 'batch' mode from macro files :
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```
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% ./TestEm17 allproc.mac
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```
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- Execute TestEm17 in 'interactive mode' with visualization :
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```
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% ./TestEm17
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Idle> control/execute vis.mac
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....
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Idle> type your commands
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....
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Idle> exit
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```
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