How do nonradioactive substances become radioactive?

Answer 1

We can make nonradioactive substances radioactive by exposing them to particulate radiation of some kind. (Electromagnetic radiation like gamma rays won't work.) There are sever kinds of particulate radiation, and they include neutrons, protons and alpha particles as well as beta particles. Exposure of a material to these particles allows the particles to activate the material, and the result of activation will depend on the radiation being used and the reaction of the substance to that activating particle flux. Just to supply one example, if we take a slug of cobalt (cobalt-59) and lower it into a working nuclear reactor, the neutron flux will bathe the cobalt. Neutrons will be absorbed by some of the cobalt atoms and they will transform into cobalt-60, which is an unstable isotope of cobalt. It's radioactive, and is a gamma ray emitter. We then withdraw the slug (now called a source) and put it in a "vault" to store it, and we use the slug (opening the vault door by remote control) as a radiation source to, say, perform X-ray analysis of pipe welds in the field where dragging an X-ray machine to the job isn't practical.