Even half-lives of radioactive isotopes of the same elements differ. In the above graph, if there were 1000 original units of radioactivity, it would decrease or decay to 500 units in the first half-life. Another factor is that there are different types of radiation known as alpha, beta, and gamma. The major concern about the different types of radiation is that they have different penetrating distances. Penetrating Distance of Radiation Alpha is made up of 2 protons and 2 neutrons with a positive electric charge.
Beta radiation is basically an electron with a negative electric charge.
When compared to the size of atoms, these forms of radiation are very small. The energy from radiation is absorbed when the radiation ionizes or comes in contact with the electrons or nuclei of other atoms, similar to a cue ball hitting other billiard balls. The energy from a cue ball is absorbed by hitting other balls and cushion before it comes to rest. The same is true of radiation except that the alpha and beta particles and gamma rays are absorbed into another atom and do not come to rest by themselves. Since alpha is a bigger particle than beta, less shielding material and thickness is needed to shield alpha particles.