Gabriele Cosmo
244 lines
11 KiB
Plaintext
244 lines
11 KiB
Plaintext
$Id: README,v 1.2 2006/11/18 01:37:22 asaim Exp $
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-------------------------------------------------------------------
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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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ExampleRE02
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-----------
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This example simulates a simplified water phantom measurement
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in medical application with demonstration of primitive scorers.
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This example also demonstrates nested parameterised volume which
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realizes segmented boxes using a combination of replicated volumes
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and a parameterised volume.
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(Tips)
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This example creates 100 x 100 x 200 boxes using Nested Parameterised
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Volume for realistic situation of medical application.
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This is very memory consumption if normal Parameterised Volume is used,
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and needs roughly more than 1 GB memory for execution. However,
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NestedParameterised volume effectively works to reduce the memory consumption,
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and it only needs less than 100 MB memory for execution.
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1- GEOMETRY DEFINITION
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The setup contains a water phantom as target by default. The world volume
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is 200 cm x 200 cm x 200 cm box filled with air. The water phantom is box shape
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and the size of 200 mm x 200 mm x 400 mm. The volume of water phantom is divided
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into 100 x 100 x 1 towers using replicated volume,(RE02DetectorConstruction),
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and then those towers are segmented into 200 boxes with respect to z axis
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using nested parameterized volume,(RE02NestedPhantomParameterisation).
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e.g. The volume of water phantom is divided into 100 x 100 x 200 boxes,
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and a voxel size is 2.0 mm x 2.0 mm x 2.0 mm.
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For demonstration purpose of the nested parameterised volume,
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(RE02NestedPhantomParameterisation), materials are assigned as water (lead)
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in even (odd) order segments, alternately.
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The simulation for homogeneous water phantom is also possible using an option.
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---- Tips(1)
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*If you want to reduce number of segments of water phantom,
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please change following numbers which represent number of segments
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in x, y, z axis, respectively.The following code can be found in
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exampleRE02.cc.
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RE02DetectorConstruction* detector = new RE02DetectorConstruction;
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detector->SetNumberOfSegmentsInPhantom(100,100,200);
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Nx, Ny, Nz
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---- Tips(2)
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*If you want to set all materials to water,
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please use the following method. The following code can be found in
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exampleRE02.cc.
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detector->SetLeadSegment(FALSE); // Homogeneous water phantom
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----
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The geometry and sensitive detector are constructed in
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RE02DetectorConstruction class.
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(See "4- SCORER " for detail descriptions about sensitive detector.)
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2- PHYSICS LIST
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The particle's type and the physic processes which is available
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in this example are set in PhysicsList class.
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The PhysicsList is originally copied from extended example,
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(example/extended/analysis/A01).
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Full set of particles (baryons, bosons and mesons) are created, and
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Standard EM Physics and Low/High Energy parameterized models
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for hadrons are applied. The detail description will be found in
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example/extended/analysis/A01/README.
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Specially, the PhysicsList was modified in this example,
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to use Binary cascade model for hadron physics at low energy (<4GeV)
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and inelastic process for generic ions with BinaryLightIonReaction.
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The data files for physics processes have to be assigned using
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environment variables.
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RE02PhysicsList is optimized for robustness and is not optimized for
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any particular cases. If you will do precise calculation for your
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use-case, please consider utilizing hadronic_lists, and defines the
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production cut properly.
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The default CutValue defines the production threshold of secondary
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particles (mainly Ionisation and Bremsstrahlung processes are
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concerned by this CutValue).
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3- RUNS and EVENTS
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- Primary particles.
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The primary kinematics consists of a single particle which hits the
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target perpendicular to the input face. The default type of the particle
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and its energy are set in the RE02PrimaryGeneratorAction class.
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However it can be changed via the G4 build-in commands of ParticleGun
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class.
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The RE02PrimaryGeneratorAction class introduces a beam spot size
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that makes initial particle position of x,y randomized using a Gaussian
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random function, where the center position is fixed to (0,0).
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The standard deviation of the beam spot size is given in
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RE02PrimaryGeneratorAction as 10 mm.
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An EVENT represents a simulation of one primary particle.
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A RUN is a set of events.
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The user has control:
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-at Begin and End of each run (class RunAction)
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-at Begin and End of each event (class EventAction)
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-at Begin and End of each track (class TrackingAction, not used here)
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-at End of each step (class SteppingAction, not used here)
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4- SCORER
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- Concrete Scorer
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This example introduces concrete primitive scorer (PS) and filter
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classes for easy scoring. Those primitive scorers are registered to
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MultiFunctionalDetector which is a concrete class of sensitive
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detector(SD). Then the MultiFunctionalDetector is attached to
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the logical volume of sensitive geometry.
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A MultiFunctionalDetector, PrimitiveScorers, and SDFilters are
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created and assigned to the logical volume of water phantom in
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DetectorConstruction.
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A primitive scorer can score one kind of physical quantity, and
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creates one hits collection per event. The quantity is collected in
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G4THitsMap with the copy number of geometry. Here collection name is
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given as <MultiFunctionalDetector Name>/<PrimitiveScorer Name>.
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A primitive scorer can have one filter (SDFilter) for selecting hits
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to be used for the quantity.
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Since the geometry is constructed using nested parameterisation,
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the copy number of geometry is defined as follows,
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copy number of geometry = iy*Nx*Ny+ix*Nz+iz,
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where Nx,Ny,Nz is total number of segmentation in x, y, and z axis,respectively,
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and ix,iy,iz is a copy number of the mother volume, the grand mother volume,
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and this volume, respectively.
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This conversion is described in GetIndex() method in PrimitiveScorer.
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The physical quantities scored in this example are:
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----------------------------------------------------
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- Total energy deposit
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unit: Energy, collName: totalEDep
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- Energy deposit by protons
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unit: Energy, collName: protonEDep
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- Number of steps of protons
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unit: - , collName: protonNStep
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- Cell Flux of charged tracks which pass through the geometry
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unit: Length/Volume, collName: chargedPassCellFlux
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- Cell Flux of all charged tracks
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unit: Length/Volume, collName: chargedCellFlux
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- Flux of charged particle at -Z surface of the BOX geometry,
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where incident angle at the surface is taken into account.
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unit: Surface^(-1), collName: chargedSurfFlux
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- Surface current of gamma at -Z surface of the BOX geometry.
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The energy of gammas are from 1. keV to 10. keV.
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The incident angle is not taken into account.
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unit: Surface^(-1), collName: gammaSurfCurr000
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- Same as previous one, but different energy bin.
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The energy of gammas are from 10. keV to 100. keV.
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unit: Surface^(-1), collName: gammaSurfCurr001
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- Same as previous one, but different energy bin.
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The energy of gammas are from 100. keV to 1. MeV.
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unit: Surface^(-1), collName: gammaSurfCurr002
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- Same as previous one, except for energy bin.
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The energy of gammas are from 1. MeV to 10. MeV.
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unit: Surface^(-1), collName: gammaSurfCurr003
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-------------------------------------------------
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- Accumulating quantities during a RUN
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A PrimitiveScorer creates one hits collection per event.
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The physical quantity in the hits collection need to be accumulated
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into another G4THitsMap object during a RUN, in order to obtain
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integrated flux or dose in a RUN. The accumulation of quantities
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are done at RE02Run class.
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RE02Run class can automatically generate G4THitsMap objects for a RUN,
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and accumulate physical quantities of an event into it. The accumulation
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is done at RE02Run::RecordEvent(G4Event* aEvent).
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- Generate a Run object, and print results
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The RE02Run object is generated at RE02RunAction::GenerateRun().
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The accumulated physical quantities are printed at the end of RUN
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( RE02RunAction::EndOfEvent() ). This example prints only selected
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physical quantities.
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5- VISUALIZATION
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The Visualization Manager is set in the main().
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The initialization of the drawing is done via a set of /vis/ commands
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in the macro vis.mac. This macro is automatically read from
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the main when running in interactive mode.
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The tracks are automatically drawn at the end of event and erased at
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the beginning of the next run.
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The visualization (with OpenGL driver) assumes two things:
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1- the visualization & interfaces categories have been compiled
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with the environment variable G4VIS_BUILD_OPENGLX_DRIVER.
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2- exampleRE02.cc has been compiled with G4VIS_USE_OPENGLX.
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(The same with DAWNFILE instead of OPENGLX)
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6- USER INTERFACES
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The default command interface, called G4UIterminal, is done via
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standard G4cin/G4cout.
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On Linux and Sun-cc on can use a smarter command interface G4UItcsh.
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It is enough to set the environment variable G4UI_USE_TCSH before
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compiling exampleRE02.cc
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7- HOW TO START ?
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- compile and link to generate an executable
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% cd RE02
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% gmake
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- execute RE02 in 'batch' mode from macro files (without visualization)
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% exampleRE02 run1.mac
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- execute RE02 in 'interactive mode' with visualization
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% exampleRE02
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....
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Idle> type your commands. For instance:
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Idle> /run/beamOn 10
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....
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Idle> /control/execute run2.mac
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....
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Idle> exit
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- macros are for different primary particles.
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vis.mac : 200 MeV proton with visualization
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run1.mac : 150 MeV proton
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run2.mac : 195 MeV/u Carbon ion
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run3.mac : 30 MeV electron
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run4.mac : 60 keV gamma
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