Gabriele Cosmo
119 lines
4.6 KiB
Plaintext
119 lines
4.6 KiB
Plaintext
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=========================================================
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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=========================================================
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Hadr04
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------
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This example is focused on neutronHP physics, especially neutron transport,
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including thermal scattering.
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See A.R. Garcia, E. Mendoza, D. Cano-Ott presentation at G4 Hadronic group
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meeting (04/2013) and note on G4NeutronHP package
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1- MATERIALS AND GEOMETRY DEFINITION
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It is a single box representing a 'quasi infinite' 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 m3 of pressurized water) is built in
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DetectorConstruction, but the above parameters can be changed interactively
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via commands defined in DetectorMessenger.
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A function, and its associated UI command, allows to build a material
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directly from a single isotope.
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To be identified by the ThermalScattering module, the elements composing a
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material must have a specific name (see G4NeutronHPThermalScatteringNames.cc)
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Examples of such materials are build in DetectorConstruction.
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2- PHYSICS LIST
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Only processes of neutronHP package are registered : neutronElastic
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(including thermalScattering), neutronInelastic, nCapture; nFission.
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See class NeutronHPphysics.
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No other hadronic nor electromagnetic processes are registered.
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A command allows to select or not ThermalScattering model.
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Several hadronic physics options are controlled by environment variables.
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To trigger them, an envHadronic.csh has been added in this example.
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One must select the options wished, and do
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source envHadronic.csh (or sh)
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NB. class NeutronHPphysics can be reused with other physicsConstructors,
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as neutron processes are deleted before to be re-created.
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3- AN EVENT : THE PRIMARY GENERATOR
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The primary kinematic is a single particle randomly shooted at the
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centre of the box. The type of the particle and its energy are set in
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PrimaryGeneratorAction (neutron 2 MeV), 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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4- PHYSICS
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All secondaries are killed in StackingAction. Therefore an event consists of
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the transport of the primary neutron. Then one survey the thermal and non
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thermal part of this parcours.
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5- HISTOGRAMS
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The test contains 7 built-in 1D histograms, which are managed by
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G4AnalysisManager and its Messenger. The histos can be individually
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activated with the command :
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/analysis/h1/set id nbBins valMin valMax unit
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where unit is the desired unit for the histo (MeV or keV, etc..)
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(see the macros xxxx.mac).
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1 "incident neutron: nb of collisions above 1 eV"
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2 "incident neutron: total track length above 1 eV"
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3 "incident neutron: time of flight above 1 eV"
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4 "incident neutron: nb of collisions below 1 eV"
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5 "incident neutron: total track length below 1*eV"
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6 "incident neutron: time of flight below 1 eV"
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7 "incident neutron: energy distribution below 1*eV"
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The histograms are managed by the HistoManager class and its Messenger.
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The histos can be individually activated with the command :
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/analysis/h1/set id nbBins valMin valMax unit
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where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
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One can control the name of the histograms file with the command:
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/analysis/setFileName name (default Hadr04)
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It is possible to choose the format of the histogram file : root (default),
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xml, csv, by using namespace in HistoManager.hh
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It is also possible to print selected histograms on an ascii file:
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/analysis/h1/setAscii id
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All selected histos will be written on a file name.ascii (default Hadr04)
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6- 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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> /control/execute vis.mac
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The detector has a default view which is a longitudinal view of the 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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7- HOW TO START ?
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Execute Hadr04 in 'batch' mode from macro files :
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% Hadr04 run01.mac
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Execute Hadr04 in 'interactive mode' with visualization :
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% Hadr04
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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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