Chapter 6
Calorimetry
Particle Detectors and Detector Systems
C. W. Fabjan and D. Fournier
6.1 Introduction, Definitions
In particle physics, calorimetry refers to the absorption of a particle and the
transformation of its energy into a measurable signal related to the energy of
the particle. In contrast to tracking a calorimetric measurement implies that the
particle is completely absorbed and is thus no longer available for subsequent
measurements.
If the energy of the initial particle is much above the threshold of inelastic
reactions between this particle and the detector medium, the energy loss process
leads to a cascade of lower energy particles, in number commensurate with the
incident energy. The charged particles in the shower ultimately lose their energy
through the elementary processes mainly by ionization and atomic level excitation.
The neutral components in the cascade (γ, n,..) contribute through processes
described later in this section.
The sum of the elementary losses builds up the calorimetric signal, which can be
of ionization or of scintillation nature (or Cherenkov) or sometimes involve several
types of response.
While the definition of calorimetry applies to both the low energy case (no
showering) and the high energy case (showering), this section deals mostly with
the showering case. Examples of calorimetry without showering are discussed in
Sect. 6.2.3.
C. W. Fabjan
Austrian Academy of Sciences and University of Technology, Vienna, Austria
e-mail: Chris.Fabjan@cern.ch
D. Fournier ()
IJCLab, Université Paris-Saclay, CNRS/IN2P3, Orsay, France
e-mail: daniel.fournier@cern.ch
© The Author(s) 2020
C. W. Fabjan, H. Schopper (eds.), Particle Physics Reference Library,
https://doi.org/10.1007/978-3-030-35318-6_6
201
Calorimetry
Particle Detectors and Detector Systems
C. W. Fabjan and D. Fournier
6.1 Introduction, Definitions
In particle physics, calorimetry refers to the absorption of a particle and the
transformation of its energy into a measurable signal related to the energy of
the particle. In contrast to tracking a calorimetric measurement implies that the
particle is completely absorbed and is thus no longer available for subsequent
measurements.
If the energy of the initial particle is much above the threshold of inelastic
reactions between this particle and the detector medium, the energy loss process
leads to a cascade of lower energy particles, in number commensurate with the
incident energy. The charged particles in the shower ultimately lose their energy
through the elementary processes mainly by ionization and atomic level excitation.
The neutral components in the cascade (γ, n,..) contribute through processes
described later in this section.
The sum of the elementary losses builds up the calorimetric signal, which can be
of ionization or of scintillation nature (or Cherenkov) or sometimes involve several
types of response.
While the definition of calorimetry applies to both the low energy case (no
showering) and the high energy case (showering), this section deals mostly with
the showering case. Examples of calorimetry without showering are discussed in
Sect. 6.2.3.
C. W. Fabjan
Austrian Academy of Sciences and University of Technology, Vienna, Austria
e-mail: Chris.Fabjan@cern.ch
D. Fournier ()
IJCLab, Université Paris-Saclay, CNRS/IN2P3, Orsay, France
e-mail: daniel.fournier@cern.ch
© The Author(s) 2020
C. W. Fabjan, H. Schopper (eds.), Particle Physics Reference Library,
https://doi.org/10.1007/978-3-030-35318-6_6
201