Chapter 2
The Interaction of Radiation with Matter
Hans Bichsel and Heinrich Schindler
2.1 Introduction
The detection of charged particles is usually based on their electromagnetic
interactions with the electrons and nuclei of a detector medium. Interaction with
the Coulomb field of the nucleus leads to deflections of the particle trajectory
(multiple scattering) and to radiative energy loss (bremsstrahlung). Since the latter,
discussed in Sect. 2.4.1, is inversely proportional to the particle mass squared, it is
most significant for electrons and positrons.
“Heavy” charged particles (in this context: particles with a mass M exceeding
the electron mass m) passing through matter lose energy predominantly through
collisions with electrons. Our theoretical understanding of this process, which has
been summarised in a number of review articles [1–7] and textbooks [8–13], is based
on the works of some of the most prominent physicists of the twentieth century,
including Bohr [14, 15], Bethe [16, 17], Fermi [18, 19], and Landau [20].
After outlining the quantum-mechanical description of single collisions in terms
of the double-differential cross section d
2 σ/ (dEdq), where E and q are the
energy transfer and momentum transfer involved in the collision, Sect. 2.3 discusses
algorithms for the quantitative evaluation of the single-differential cross section
The author Hans Bichsel is deceased at the time of publication.
H. Bichsel · H. Schindler ()
CERN, Geneva, Switzerland
e-mail: Heinrich.Schindler@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_2
5
The Interaction of Radiation with Matter
Hans Bichsel and Heinrich Schindler
2.1 Introduction
The detection of charged particles is usually based on their electromagnetic
interactions with the electrons and nuclei of a detector medium. Interaction with
the Coulomb field of the nucleus leads to deflections of the particle trajectory
(multiple scattering) and to radiative energy loss (bremsstrahlung). Since the latter,
discussed in Sect. 2.4.1, is inversely proportional to the particle mass squared, it is
most significant for electrons and positrons.
“Heavy” charged particles (in this context: particles with a mass M exceeding
the electron mass m) passing through matter lose energy predominantly through
collisions with electrons. Our theoretical understanding of this process, which has
been summarised in a number of review articles [1–7] and textbooks [8–13], is based
on the works of some of the most prominent physicists of the twentieth century,
including Bohr [14, 15], Bethe [16, 17], Fermi [18, 19], and Landau [20].
After outlining the quantum-mechanical description of single collisions in terms
of the double-differential cross section d
2 σ/ (dEdq), where E and q are the
energy transfer and momentum transfer involved in the collision, Sect. 2.3 discusses
algorithms for the quantitative evaluation of the single-differential cross section
The author Hans Bichsel is deceased at the time of publication.
H. Bichsel · H. Schindler ()
CERN, Geneva, Switzerland
e-mail: Heinrich.Schindler@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_2
5