Why is beta radiation used in Monitoring the thickness of materials ?
This is because Beta radiation isnt very penetrative. For example, beta can be given off by a source a fixed distance from the paper. And then a detector a set distance away from the paper is placed on the other side, therefore the detector can measure how many counts per second. If this stays constant, then the paper remains at a certain thickness. If the paper gets thinner, more Beta radiatin gets through and this alerts the machine making the paper which can then fix the problem. Gamma Radiation isnt used because it would pass straight through the detector, as it doesnt get stopped until it passes through extremely thick things like Lead, there fore this would be a useless option. Alpha Radiation isnt used because its not penetrating enough. It gets blocked by most things, for example a sheet of paper, therefore it wouldnt reach the detector on the other side. Beta is Medium penetrative which means it is the best option.
