5 Interactions of Beams with Surroundings
187
5.1.2.2 GEANT4
GEANT4 is an object-oriented toolkit originally designed to simulate detector
responses of modern particle and nuclear physics experiments [3, 4]. It consists of
a kernel which provides the framework for particle transport, including tracking,
geometry description, material specifications, management of events and interfaces
to external graphics systems.
The kernel also provides interfaces to physics processes. In this regard the
flexibility of GEANT4 is unique as it allows the user to select freely the physics
models which serve best the particular application needs. This freedom comes
with high responsibility as the user must ensure that the most adequate models
are used for a given problem. Implementations of interaction models exist over
an extended range of energies, from optical photons and thermal neutrons to high
energy interactions as required for the simulation of accelerator and cosmic ray
experiments. In many cases complementary or alternative modelling approaches are
offered from which the user can choose.
Descriptions of intranuclear cascades include implementations of the Binary
and the Bertini cascade models (the latter significantly reworked and not at all
linked to the original Bertini model). Both are valid for interactions of nucleons
and charged mesons, the former for energies below 3 GeV and the latter below
10 GeV. The Intranuclear Cascade of Liège (INCL) is also an usable option.
At higher energies (up to 10 TeV), three models are available: a high-energy
parameterized model (using fits to experimental data), a quark-gluon string model
and the Fritiof fragmentation model, both based on string excitations and decay into
hadrons. Nuclear de-excitation models include abrasion-ablation and Fermi-breakup
models. Furthermore, heavy ion interactions can also be simulated if the appropriate
packages are linked.
The package for electromagnetic physics comprises the standard physics processes as well as extensions to energies below 1 keV, including emissions of X-rays,
optical photon transport, etc.
5.1.2.3 MARS15
The MARS15 code system [5, 6] is a set of Monte Carlo programs for the simulation
of hadronic and electromagnetic cascades which is used for shielding, accelerator
design and detector studies. Correspondingly, it covers a wide energy range:
100 keV–100 TeV for muons, charged hadrons and heavy ions, 1 keV–100 TeV for
electromagnetic showers and down to 0.00215 eV for neutrons.
Hadronic interactions above 5 GeV can be simulated with either an inclusive
or an exclusive event generator. While the former is CPU-efficient (especially at
high energy) and based on a wealth of experimental data on inclusive interaction
spectra, the latter provides final states on a single interaction level and preserves
correlations. In the exclusive mode, the cascade-exciton model code CEM03,
the Quark-Gluon String Model code LAQGSM03 and the DPMJET3 code are
187
5.1.2.2 GEANT4
GEANT4 is an object-oriented toolkit originally designed to simulate detector
responses of modern particle and nuclear physics experiments [3, 4]. It consists of
a kernel which provides the framework for particle transport, including tracking,
geometry description, material specifications, management of events and interfaces
to external graphics systems.
The kernel also provides interfaces to physics processes. In this regard the
flexibility of GEANT4 is unique as it allows the user to select freely the physics
models which serve best the particular application needs. This freedom comes
with high responsibility as the user must ensure that the most adequate models
are used for a given problem. Implementations of interaction models exist over
an extended range of energies, from optical photons and thermal neutrons to high
energy interactions as required for the simulation of accelerator and cosmic ray
experiments. In many cases complementary or alternative modelling approaches are
offered from which the user can choose.
Descriptions of intranuclear cascades include implementations of the Binary
and the Bertini cascade models (the latter significantly reworked and not at all
linked to the original Bertini model). Both are valid for interactions of nucleons
and charged mesons, the former for energies below 3 GeV and the latter below
10 GeV. The Intranuclear Cascade of Liège (INCL) is also an usable option.
At higher energies (up to 10 TeV), three models are available: a high-energy
parameterized model (using fits to experimental data), a quark-gluon string model
and the Fritiof fragmentation model, both based on string excitations and decay into
hadrons. Nuclear de-excitation models include abrasion-ablation and Fermi-breakup
models. Furthermore, heavy ion interactions can also be simulated if the appropriate
packages are linked.
The package for electromagnetic physics comprises the standard physics processes as well as extensions to energies below 1 keV, including emissions of X-rays,
optical photon transport, etc.
5.1.2.3 MARS15
The MARS15 code system [5, 6] is a set of Monte Carlo programs for the simulation
of hadronic and electromagnetic cascades which is used for shielding, accelerator
design and detector studies. Correspondingly, it covers a wide energy range:
100 keV–100 TeV for muons, charged hadrons and heavy ions, 1 keV–100 TeV for
electromagnetic showers and down to 0.00215 eV for neutrons.
Hadronic interactions above 5 GeV can be simulated with either an inclusive
or an exclusive event generator. While the former is CPU-efficient (especially at
high energy) and based on a wealth of experimental data on inclusive interaction
spectra, the latter provides final states on a single interaction level and preserves
correlations. In the exclusive mode, the cascade-exciton model code CEM03,
the Quark-Gluon String Model code LAQGSM03 and the DPMJET3 code are