Radioactivity - The Changing Arctic Environment: The Arctic Messenger - page 46

( 14 C). Finally, there are fission products, such as caesium-137 ( 137 Cs), strontium-90 ( 90 Sr)
and iodine-131 ( 131 I), and activation products, such as cobalt-60 ( 60 Co), which are all an-
thropogenic. Fission products have atomic masses in the range of 70 to 170 and are formed
by the thermal fission of heavy nuclei, such as 238 U. Activation products result from neut-
ron capture by stable nuclei in artificial high-neutron conditions, such as reactor cores and
accelerators. They generally decay by γ ray and β particle emission.
Radiation that is so energetic that it can overcome the binding energy of electrons to
atoms or molecules creates ions - a situation where the electric charge of the nucleus is no
longer balanced by the charge of the electrons. Ionizing radiation is capable of disrupting
the internal structure of biological molecules, including DNA. Gamma ( γ ) ray and alpha
( α ) and beta ( β ) particle emissions are all examples of ionizing radiation.