ABSTRACT
In the previous chapter, we discussed the time variation of intensities of nuclear emissions in radioactive decays. Our concern was only those cases in which decays are possible. Now we must address the question why some nuclei decay while others do not. Also, nuclei decay by emitting a few select types of radiation but not all types. For example, a 14C nucleus with a half-life of 5730 years decays by emitting a beta particle, but it does not emit an alpha particle or a proton or something else. Gamma rays are not emitted. In most cases, daughter nuclei produced in nuclear decays emit gamma rays, but they do not emit neutrons or protons or other complex nuclei. Also, physicists and industry have been producing several nuclei by artificial means with particle accelerators and nuclear reactors. How do they go about it? A further concern is what happens when these emitted particles interact with materials as they travel through a medium. Is it possible that they produce secondary particles such as neutrons, gamma rays or some other particles or some new isotopes? If yes, under what conditions are they produced?
