Geology Reference
In-Depth Information
Figure 4.1
A natural gamma-ray spectrum. Note that the vertical scale
(numbers of counts) is logarithmic.
measured spectrum is shown in Figure 4.1. The individual peaks correspond
to specific decay events. Their widths are determined by the kinetic energies
of the decaying nuclei and by errors in measurement.
The background curve upon which the peaks are superimposed represents
terrestrial and cosmic radiation that has been
scattered
, i.e. has lost some of
its initial energy. Photons with energies above 1 MeV may produce electron-
positron pairs when passing close to atomic nuclei, and the positrons will
interact with other electrons to produce less energetic photons. At lower
