Using gamma radiation from Cobalt 60 is used to sterilise syringes:
Gamma rays, emitted from cobalt-60, are similar in many ways to microwaves and X-rays. Gamma rays delivered during sterilization break chemical bonds by interacting with the electrons of atoms, which would kill anything made of atoms (which is everything). And although gamma rays are highly effective in killing micro-organisms, they leave no residues nor have sufficient energy to impart radioactivity. Also the gamma rays can be used over and over again, with hardly any time preparing them, as would be the case in steam sterilising. Furthermore gamma rays do not require high pressures or vacuum.
Using beta radiation to determine the thickness of paper:
When beta particles (electrons) strike material, some of them will pass through, while others will be stopped. The thicker (or more dense) the material, the more likely it is that a particle will be stopped.
By measuring the amount of particles coming through the paper, the correct thickness can be achieved.
In order to make an accurate measurement, it is important that the material not be so thick that it stops all (or too many) of the beta particles. It is also important that it stops enough of them. If it is too thin, so few of the beta particles will be stopped that it will be difficult to measure the number that are stopped, only a very small number of beta particles will be stopped. Strontium (Sr90) is the beta source that is most commonly used. It is suitable for measuring the thickness because it emits a lot of particles, so even minor differences the paper thickness could be detected.
Radioactive elements and their use in smoke detectors:
Ionisation smoke detectors use an ionization chamber and a source of ionising radiation...