Does the amount of radiation (cpm) change when shielding made from different material is used?
The type of shielding used to block various kinds of radiation makes a huge difference depending on the type of radiation present. There are three basic types of radiation: alpha, beta, and gamma. Alpha radiation produces alpha particles. This is a relatively weak radiation that can be blocked with a simple sheet of paper. Beta radiation particles are stronger and will penetrate paper but can be stopped by a thin sheet of metal like aluminum. Gamma radiation is not composed of particles but electromagnetic photons instead. It is a much more powerful radiation and requires a lead barrier for effective shielding. So you can see that the type of shielding used matters greatly on the type of radiation present.