Physics and Engineering of Radiation Detection

30 Chapter 1. Properties and Sources of Radiation

Table 1.5.1: Common Radioactive Isotopes of Elements

Element Common Isotopes Common Use

(Decay Mode)

Cobalt Co^6027 (β) Surgical instrument sterilization

Technetium Tc^9943 (β) Medical diagnostics

Iodine I 53123 (β, EC),I 53129 (β),I 53131 (β) Medical diagnostics

Xenon Xe^13354 (β) Medical diagnostics

Caesium Cs^13755 (β) Treat cancers

Iridium Ir^19277 (β) Integrity check of welds and parts

Polonium Po^21084 (α) Static charge reduction in

photographic films

Thorium Th^22990 (α) Extend life of fluorescent lights

Plutonium Pu^23894 (α) α-particle source

Americium Am^24195 (α) Smoke detectors

1.6 General Properties and Sources of Particles and Waves

The interaction of particles with atoms is governed by quantum mechanical processes
that depend on the properties of both incident particles and target atoms. These
properties include mass, electrical charge, and energy. In most of the cases, the
target atoms can be considered to be at rest with respect to the incident particles,
which greatly simplifies the mathematical manipulations to predict their properties
after the interaction has taken place.
Strictly speaking it is not absolutely necessary to know the internal structure (if
any) of a particle to understand its gross properties (except for properties, such as
magnetic moment of a neutron, which are not needed in usual radiation detection).
However to make our discussion complete, let’s have a look at our present knowledge
about the elementary particles. On the fundamental level there are only a few parti-
cles, which in different combinations form heavier and stable particles. For example
both proton and neutron are composed of 3 fundamental particles called quarks.
The nature of these quarks determines whether it is a proton or a neutron. There is
an extremely successful model in particle physics, called the Standard Model, which
tells us that there are 6 types of quarks and another breed of elementary particles
called leptons. These are the particles that are not known to have any internal