<IMG SRC="navi.gif" WIDTH=160 HEIGHT=440 usemap="#navi" BORDER=0> Particle Decays And Annihilations : Radioactive Particles

Scientists eventuallyidentified several distinct types of radiation, the particles resulting from radioactive decays. The three distinct types of radiation were named after the first three letters of the Greek alphabet: (alpha), (beta), and (gamma).

Alpha particles are helium nuclei (2 p, 2 n):

Beta particles are speedy electrons:

Gamma radiation is a high-energy photon:

These three forms of radiation can be distinguished by a magnetic field since alpha particles, which have positive charge, curve in one direction, beta particles, which are negative, curve in an opposite direction, and electrically neutral gamma radiation doesn't curve at all.

Alpha particles can be stopped by a sheet of paper, beta particles by aluminum, and gamma radiation by a block of lead. Gamma radiation can penetrate very far into a material, and so it is gamma radiation that poses the most danger when working with radioactive materials, although all types of radiation are very dangerous. Sadly, it took scientists many years to realize the perils of radioactivity...