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Celeritas

The celeritas directory focuses on the physics and transport loop implementation for the Celeritas codebase, using components from the corecel and orange dependencies.

Fundamentals

.. doxygennamespace:: units


.. doxygennamespace:: constants


.. doxygenfile:: celeritas/Units.hh
   :sections: user-defined var innernamespace


.. doxygenfile:: celeritas/Quantities.hh
   :sections: user-defined var innernamespace


.. doxygenfile:: celeritas/Constants.hh
   :sections: user-defined var innernamespace

Problem definition

.. doxygenclass:: celeritas::MaterialParams


.. doxygenclass:: celeritas::ParticleParams


.. doxygenclass:: celeritas::PhysicsParams

Transport interface

.. doxygenclass:: celeritas::Stepper

Geant4 physics interfaces

.. doxygenclass:: celeritas::GeantImporter


.. doxygenclass:: celeritas::GeantSetup

Geant4 physics options

.. doxygenstruct:: celeritas::GeantPhysicsOptions

Geometry interfaces

.. doxygenclass:: celeritas::VecgeomParams


.. doxygenclass:: celeritas::GeantGeoParams

On-device access

.. doxygenclass:: celeritas::MaterialTrackView


.. doxygenclass:: celeritas::ParticleTrackView


.. doxygenclass:: celeritas::PhysicsTrackView

Random number distributions

The 2011 ISO C++ standard defined a new functional paradigm for sampling from random number distributions. In this paradigm, random number engines generate a uniformly distributed stream of bits. Then, distributions use that entropy to sample a random number from a distribution. Distributions are function-like objects whose constructors take the parameters of the distribution: for example, a uniform distribution over the range [a, b) takes the a and b parameters as constructor arguments. The templated call operator accepts a random engine as its sole argument.

Celeritas extends this paradigm to physics distributions. At a low level, it has :ref:`random number distributions <celeritas_random>` that result in single real values (such as uniform, exponential, gamma) and correlated three-vectors (such as sampling an isotropic direction).

.. doxygenclass:: celeritas::BernoulliDistribution
   :members: none

.. doxygenclass:: celeritas::DeltaDistribution
   :members: none

.. doxygenclass:: celeritas::ExponentialDistribution
   :members: none

.. doxygenclass:: celeritas::GammaDistribution
   :members: none

.. doxygenclass:: celeritas::IsotropicDistribution
   :members: none

.. doxygenclass:: celeritas::NormalDistribution
   :members: none

.. doxygenclass:: celeritas::PoissonDistribution
   :members: none

.. doxygenclass:: celeritas::RadialDistribution
   :members: none

.. doxygenclass:: celeritas::ReciprocalDistribution
   :members: none

.. doxygenclass:: celeritas::UniformBoxDistribution
   :members: none

.. doxygenclass:: celeritas::UniformRealDistribution
   :members: none

Physics distributions

At a higher level, Celeritas expresses many physics operations as distributions of updated track states based on original track states. For example, the Tsai-Urban distribution used for sampling exiting angles of bremsstrahlung and pair production has parameters of incident particle energy and mass, and it samples the exiting polar angle cosine.

.. doxygenclass:: celeritas::BhabhaEnergyDistribution
   :members: none


.. doxygenclass:: celeritas::EnergyLossGammaDistribution
   :members: none


.. doxygenclass:: celeritas::EnergyLossGaussianDistribution
   :members: none


.. doxygenclass:: celeritas::EnergyLossUrbanDistribution
   :members: none


.. doxygenclass:: celeritas::MollerEnergyDistribution
   :members: none


.. doxygenclass:: celeritas::TsaiUrbanDistribution
   :members: none

Physics implementations

Additional distributions are built on top of the helper distributions above. All discrete interactions (in Geant4 parlance, "post-step do-it"s) use distributions to sample an Interaction based on incident particle properties. The sampled result contains the updated particle direction and energy, as well as properties of any secondary particles produced.

.. doxygenclass:: celeritas::BetheHeitlerInteractor
   :members: none

.. doxygenclass:: celeritas::EPlusGGInteractor
   :members: none

.. doxygenclass:: celeritas::KleinNishinaInteractor
   :members: none

.. doxygenclass:: celeritas::MollerBhabhaInteractor
   :members: none

.. doxygenclass:: celeritas::LivermorePEInteractor
   :members: none

.. doxygenclass:: celeritas::RayleighInteractor
   :members: none

.. doxygenclass:: celeritas::RelativisticBremInteractor
   :members: none

.. doxygenclass:: celeritas::SeltzerBergerInteractor
   :members: none


.. doxygenclass:: celeritas::AtomicRelaxation
   :members: none

.. doxygenclass:: celeritas::EnergyLossHelper
   :members: none

.. doxygenclass:: celeritas::detail::UrbanMscStepLimit
   :members: none

.. doxygenclass:: celeritas::detail::UrbanMscScatter
   :members: none


.. doxygenclass:: celeritas::SBEnergyDistribution
   :members: none

.. doxygenclass:: celeritas::detail::SBPositronXsCorrector
   :members: none

Physics data

Celeritas reads physics data from Geant4 (or from a ROOT file exported from data previously loaded into Geant4). Different versions of Geant4 (and Geant4 data) can be used seamlessly with any version of Celeritas, allowing differences to be isolated without respect to machine or model implementation. The following classes enumerate all the data used at runtime.

.. doxygenstruct:: celeritas::ImportData
   :undoc-members:

Material and geometry properties

.. doxygenstruct:: celeritas::ImportElement
   :undoc-members:

.. doxygenstruct:: celeritas::ImportProductionCut
   :undoc-members:

.. doxygenstruct:: celeritas::ImportMatElemComponent
   :undoc-members:

.. doxygenstruct:: celeritas::ImportMaterial
   :undoc-members:

.. doxygenstruct:: celeritas::ImportVolume
   :undoc-members:

.. doxygenstruct:: celeritas::ImportTransParameters
   :undoc-members:

.. doxygenstruct:: celeritas::ImportLoopingThreshold
   :undoc-members:


.. doxygenenum:: ImportMaterialState

Physics properties

.. doxygenstruct:: celeritas::ImportParticle
   :undoc-members:

.. doxygenstruct:: celeritas::ImportProcess
   :undoc-members:

.. doxygenstruct:: celeritas::ImportModel
   :undoc-members:

.. doxygenstruct:: celeritas::ImportMscModel
   :undoc-members:

.. doxygenstruct:: celeritas::ImportModelMaterial
   :undoc-members:

.. doxygenstruct:: celeritas::ImportPhysicsTable
   :undoc-members:

.. doxygenstruct:: celeritas::ImportPhysicsVector
   :undoc-members:


.. doxygenenum:: ImportProcessType

.. doxygenenum:: ImportProcessClass

.. doxygenenum:: ImportModelClass

.. doxygenenum:: ImportTableType

.. doxygenenum:: ImportUnits

.. doxygenenum:: ImportPhysicsVectorType

EM data

.. doxygenstruct:: celeritas::ImportEmParameters
   :undoc-members:

.. doxygenstruct:: celeritas::ImportAtomicTransition
   :undoc-members:

.. doxygenstruct:: celeritas::ImportAtomicSubshell
   :undoc-members:

.. doxygenstruct:: celeritas::ImportAtomicRelaxation
   :undoc-members:


.. doxygenstruct:: celeritas::ImportLivermoreSubshell
   :undoc-members:

.. doxygenstruct:: celeritas::ImportLivermorePE
   :undoc-members:


.. doxygenstruct:: celeritas::ImportSBTable
   :undoc-members: