Radioactive alpha source mounted in approved holder with a plastic shaft, threaded for mounting in a support.
Activity: 260 kBq
Half life: 5.27 years.
The sources from Risø are designed to illustrate the chosen radiation as clearly as possible - but nothing in the world is perfect, and the details are worth knowing.
Co-60 beta decays to an excited state of Ni-60 which then decays through a cascade of two gamma emissions.
The gamma energies are 1.173 and 1.333 MeV.
The source is constructed to absorb most of the beta particles.
Ni-60 is stable.