Gabriele Cosmo
84 lines
3.2 KiB
Plaintext
84 lines
3.2 KiB
Plaintext
Example GB07 : leading particle biasing
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This example illustrates how to use the leading particle biasing option.
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It uses the G4BOptnLeadingParticle biasing operation located in:
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source/processes/biasing/generic ,
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and defines the following biasing operation to handle it:
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GB07OptrLeadingParticle.
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As a reminder, the generic biasing scheme consists of a G4VBiasingOperator
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that takes decisions on what sort of biasing technique to be applied. The
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techniques are called biasing operations, represented by the G4VBiasingOperation
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class. The operator is attached to a logical volume in which the biasing must
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happen. Decisions are made on requests of the G4BiasingProcessInterface process
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that messages the operator when the track is travelling in the volume. To equip
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the phyics list with this process, the G4GenericBiasingPhysics physics
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constructor is used. In this example, several processes -to which the technique
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is applied- are wrapped by this process to control their final state production
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for applying the biasing technique.
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Geometry:
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---------
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The geometry is simply :
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- a volume in which the biasing occurs and to which an instance of
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GB07OptrLeadingParticle is attached,
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- a thin volume placed after the above volume, that is used to tally the
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particles exiting biasing volume.
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- a sensitive detector is attached to the thin volume to simply print the
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particles entering here. In particular the statistical weight is printed,
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this one is obtained by:
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w = track->GetWeight() ;
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Biasing configuration:
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----------------------
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The particle types and processes under the leading particle biasing are
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visible in the main program exampleGB07.cc, these are:
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pi+ and pi-, inelastic process,
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proton and anti-proton, inelastic process,
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neutron, inelastic and capture processes,
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anti-neutron, inelastic process,
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gamma, conversion and photonNuclear processes,
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electron, electronNuclear process,
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positron, annihilation and positronNuceal processes,
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pi0, decay process.
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For the inelastic and lepto/gamma-nuclear processes, leading particle is applied in a rather
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classical way:
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- keep the leading particle,
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- keep one particle of each species (particles and anti-particles are considered a one
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species, and all hadrons with Z>=2 are counted as one species too).
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For e+, e-, gamma and pi0 processes (which means in practice main conversion, annihililation
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and pi0 decay processes), the leading particle is kept, and the companion track(s) is(are) randomly
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kept/killed under a Russian roulette, with a 2/3 killing probabilty. See
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GB07BOptrLeadingParticle::StartTracking( ... ) for this killing probability setting.
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Running the program:
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--------------------
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The program can be run in batch or interactive mode and has the following options:
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in batch:
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./exampleGB07 [-m macro ] [-b biasing {'on' = default,'off'}]
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or
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./exampleGB07 [macro.mac]
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interactive:
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./exampleGB07 [-b biasing {'on' = default,'off'}]
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