Radioactive decay (see radioactivity)
by emission of a beta particle. This process
proceeds via the weak interaction and
includes all nuclear decays in which the atomic
mass, A, remains constant and the atomic
number, Z, changes by one unit.
There are three main types of beta decay. They are:
Nuclei that are rich in neutrons tend
to decay by emitting an electron
along with an antineutrino. As a result, one of the neutrons in the
nucleus changes into a proton. E.g.,
decay of P-32 into S-32 or Cs-137 into Ba-137.
Neutron-deficient nuclei tend to decay by positron
emission or electron capture (see below). Positron emission refers
to the emission of a positron along with a neutrino
and the resulting conversion of a proton inside the nucleus into a
neutron. E.g., decay of Na-22 into Ne-22.
Electron capture is usually classified as a type of beta decay and
involves an orbital electron being absorbed by a nucleus, effectively
converting a proton into a neutron. E.g., K-40, Mn-54, and Fe-55 radionuclides
decay by this process.
These three types of beta decay can be summarized as follows:
The simplest beta decay process is free neutron
AND NUCLEAR PHYSICS