234
C. W. Fabjan and D. Fournier
Momentum correction to muon momenta can be applied, in setups where muons
traverse a calorimeter before entering the muon spectrometer. For muons above
~10 GeV/c there is a good correlation between the total energy loss of muons in
a calorimeter with the energy loss recorded in the active medium.
This is valuable, particularly for ‘catastrophic’ muon energy loss. Event-byevent correction for the muon energy loss is therefore useful in the hundred GeV
momentum range for muon spectrometers behind the calorimeter with few percent
momentum resolution [39].
Energy calibration and monitoring is frequently and conveniently done with
muons. Exposing a calorimeter to a beam of electrons with well-known energy sets
the ‘electron-energy scale’.
In sampling calorimeters muons deposing a given energy produce in general
more signal than electrons having deposited the same energy: e/μ < 1. While
establishing an absolute energy scale with muons requires very careful MC crosschecks, it is very convenient to use muons as a monitor of the calorimeter response
as a function of time during data taking and as intercalibration tool between different
parts of a calorimeter set-up [50]. The use of muons allows to transfer the absolute
energy calibration established in a test beam to the experimental facility and to
follow the energy calibration in situ using muons from physics channels. However,
given the large dynamic range of energy measurements in many experiments, e.g. at
the LHC and the smallness of the muon signal, complimentary calibration methods
are necessary to achieve the required accuracy, see Sect. 6.3.6.
6.2.9 Monte Carlo Simulation of Calorimeter Response
Modern calorimetry would not have been possible without extensive shower
simulations.
The first significant use of such techniques aimed to understand electromagnetic
calorimeters. For example, electromagnetic codes were used in the optimization
of NaI detectors in the pioneering work of Hofstädter, Hughes and collaborators
[51]. One code, EGS4, has become the de facto standard for electromagnetic
shower simulation [17]. Early hadronic cascade simulations were motivated by
experimental work in cosmic-ray physics [52] and sampling calorimetry [53].
However, it were the codes developed by the Oak Ridge group [54], with their
extensive modelling of nuclear physics, neutron transport, spallation and fission,
which are indissociable from the development of modern hadron calorimetry [35].
Modern, high precision calorimetry and related applications have imposed a new
level of stringent quality requirements on simulation:
– in many applications, electromagnetic effects have to be understood at the 0.1%
level, hadronic effects at the 1% level;
– ‘unorthodox’ calorimeter geometries (Sect. 6.7) have to be optimized with
simulation tools providing sophisticated interfaces to shower codes:
C. W. Fabjan and D. Fournier
Momentum correction to muon momenta can be applied, in setups where muons
traverse a calorimeter before entering the muon spectrometer. For muons above
~10 GeV/c there is a good correlation between the total energy loss of muons in
a calorimeter with the energy loss recorded in the active medium.
This is valuable, particularly for ‘catastrophic’ muon energy loss. Event-byevent correction for the muon energy loss is therefore useful in the hundred GeV
momentum range for muon spectrometers behind the calorimeter with few percent
momentum resolution [39].
Energy calibration and monitoring is frequently and conveniently done with
muons. Exposing a calorimeter to a beam of electrons with well-known energy sets
the ‘electron-energy scale’.
In sampling calorimeters muons deposing a given energy produce in general
more signal than electrons having deposited the same energy: e/μ < 1. While
establishing an absolute energy scale with muons requires very careful MC crosschecks, it is very convenient to use muons as a monitor of the calorimeter response
as a function of time during data taking and as intercalibration tool between different
parts of a calorimeter set-up [50]. The use of muons allows to transfer the absolute
energy calibration established in a test beam to the experimental facility and to
follow the energy calibration in situ using muons from physics channels. However,
given the large dynamic range of energy measurements in many experiments, e.g. at
the LHC and the smallness of the muon signal, complimentary calibration methods
are necessary to achieve the required accuracy, see Sect. 6.3.6.
6.2.9 Monte Carlo Simulation of Calorimeter Response
Modern calorimetry would not have been possible without extensive shower
simulations.
The first significant use of such techniques aimed to understand electromagnetic
calorimeters. For example, electromagnetic codes were used in the optimization
of NaI detectors in the pioneering work of Hofstädter, Hughes and collaborators
[51]. One code, EGS4, has become the de facto standard for electromagnetic
shower simulation [17]. Early hadronic cascade simulations were motivated by
experimental work in cosmic-ray physics [52] and sampling calorimetry [53].
However, it were the codes developed by the Oak Ridge group [54], with their
extensive modelling of nuclear physics, neutron transport, spallation and fission,
which are indissociable from the development of modern hadron calorimetry [35].
Modern, high precision calorimetry and related applications have imposed a new
level of stringent quality requirements on simulation:
– in many applications, electromagnetic effects have to be understood at the 0.1%
level, hadronic effects at the 1% level;
– ‘unorthodox’ calorimeter geometries (Sect. 6.7) have to be optimized with
simulation tools providing sophisticated interfaces to shower codes: