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C. W. Fabjan and D. Fournier
on the calorimetry in terms of granularity, but also on the correct association of
photonic and hadronic energy. Modeling has shown that this performance can be
achieved in principle using the concept of ‘Particle Flow Analysis’.[64, 65].
(iii) Ultra-High Energy Modelling
A particularly challenging application of these Monte Carlo techniques is extrapolation beyond present accelerator energies. The use of the Earth’s atmosphere as a
hadron calorimeter allows cosmic hadrons and nuclei up to and beyond 10 20 eV to
be probed. This requires ‘dead-reckoning’ of the detector response based on Monte
Carlo techniques. Considerable faith in the extrapolation of the simulation models is
needed in establishing the absolute energy scale. The estimate of the primary energy
is based on measuring the shower shape: knowledge of F em , the nucleon–nucleon
cross-section, particle multiplicities, transverse momentum distributions, etc., all
contribute to the estimate of the primary energy.
(iv) Low Energy Performance and Radiation Background
In many applications, e.g. dosimetry, careful modelling of the physics down to the
MeV scale is needed. Certain codes [66] have been carefully benchmarked showing
agreement to better than 20%, remarkable, as the very low-energy modelling of
nuclear physics processes is involved.
Faithful modelling is also necessary to estimate the radiation levels in the
LHC experimental caverns. Such modelling [67], based on the FLUKA code, was
the basis for a number of design criteria and choices for the ATLAS and CMS
experiments.
(v) Medical Applications
In cancer treatment with particle beams the tumour is exposed to proton or light
ion beams, such as He or C 12 , with energies of a few hundred MeV/nucleon. The
energy deposition of the beam inside the human body (here the 1/β 2 part of dE/dx is
relevant) can be monitored by positron emission tomography (PET), the β + emitters
being produced through nuclear fragmentation reactions of the beam ions with the
tissue nuclei.
Both, the patient treatment plan and the interpretation of these images is
evaluated with the same MC programs as used in particle physics. More generally,
the improvement in radiation treatments achieved with proper (particle physics)
quality simulation is very significant, a very important legacy of particle physics
to society [68].
We conclude that
– modern calorimetry owes much to Monte Carlo modelling;
– as always, predictions have to be taken with circumspection, in particular the
extrapolation to performance and energy regimes inaccessible to experimental
checks. Caveat emptor.
C. W. Fabjan and D. Fournier
on the calorimetry in terms of granularity, but also on the correct association of
photonic and hadronic energy. Modeling has shown that this performance can be
achieved in principle using the concept of ‘Particle Flow Analysis’.[64, 65].
(iii) Ultra-High Energy Modelling
A particularly challenging application of these Monte Carlo techniques is extrapolation beyond present accelerator energies. The use of the Earth’s atmosphere as a
hadron calorimeter allows cosmic hadrons and nuclei up to and beyond 10 20 eV to
be probed. This requires ‘dead-reckoning’ of the detector response based on Monte
Carlo techniques. Considerable faith in the extrapolation of the simulation models is
needed in establishing the absolute energy scale. The estimate of the primary energy
is based on measuring the shower shape: knowledge of F em , the nucleon–nucleon
cross-section, particle multiplicities, transverse momentum distributions, etc., all
contribute to the estimate of the primary energy.
(iv) Low Energy Performance and Radiation Background
In many applications, e.g. dosimetry, careful modelling of the physics down to the
MeV scale is needed. Certain codes [66] have been carefully benchmarked showing
agreement to better than 20%, remarkable, as the very low-energy modelling of
nuclear physics processes is involved.
Faithful modelling is also necessary to estimate the radiation levels in the
LHC experimental caverns. Such modelling [67], based on the FLUKA code, was
the basis for a number of design criteria and choices for the ATLAS and CMS
experiments.
(v) Medical Applications
In cancer treatment with particle beams the tumour is exposed to proton or light
ion beams, such as He or C 12 , with energies of a few hundred MeV/nucleon. The
energy deposition of the beam inside the human body (here the 1/β 2 part of dE/dx is
relevant) can be monitored by positron emission tomography (PET), the β + emitters
being produced through nuclear fragmentation reactions of the beam ions with the
tissue nuclei.
Both, the patient treatment plan and the interpretation of these images is
evaluated with the same MC programs as used in particle physics. More generally,
the improvement in radiation treatments achieved with proper (particle physics)
quality simulation is very significant, a very important legacy of particle physics
to society [68].
We conclude that
– modern calorimetry owes much to Monte Carlo modelling;
– as always, predictions have to be taken with circumspection, in particular the
extrapolation to performance and energy regimes inaccessible to experimental
checks. Caveat emptor.