Principle

The intensity of gamma-radiation decreases when it passes
through solid matter. The attenuation can be the result of Compton
scattering, the photo effect or the pair production. An absorption
coefficient can be attributed to each of the three phenomena. These
absorption coefficients, as well as the total absorption, are
highly energy-dependent. The energy dependence of the total
absorption coefficient for aluminium in the range below 1.3 MeV is
verified.

Tasks


For each of the emitting isotopes 22Na and 241Am the
gamma-spectrum is traced and a threshold energy, E, just below the
photo-peak in the high energy range determined.

Using the scintillation counter in conjunction with the pulse
height analyser as a monochromator, the gamma-intensity is measured
as a function of the thickness of different aluminium layers.The
three gamma- emitting isotopes are used successively as the source,
assuming that the energy of the emitted gamma-radiation is
known.


What you can learn about


Compton scattering

Photo effect

Pair production

Absorption coefficient

Radioactive decay

g-spectroscopy


Software included. Computer not provided.