Question: can gamma radiation waves penetrate lead and concrete?

Lindy Heath answered on 14 Jun 2012:

Radioactive substances emit (give out) radioactive radiation all of the time. There are three types of radioactive radiation, so called nuclear radiation, called alpha, beta and gamma. They are called nuclear radiation because the radiation comes from the nucleus of the atom. Alpha radiation is the least penetrating, beta radiation slightly more penetrating and gamma radiation the most penetrating. So what does this mean? Well, radiation can be absorbed by any substances in its path but as the distance from the radioactive material increases,the intensity of the radiation decreases as the particles or rays become more spread out. Alpha radiation can only travel a few centimetres in air and can be stopped (or absorbed) by a sheet of paper. Beta radiation can travel a bit further, around tens of centimetres in air so a thicker substance is required to absorb the radiation. Beta radiation can be stopped by a thin sheet of aluminium. Gamma radiation however can travel for many meters so it requires a material much thicker to absorb it. For example, many centimetres of lead or many meters of concrete will absorb gamma radiation. So to absorb gamma radiation, it is the thickness of the material which is important as well as the density of the material. This means that gamma radiation can penetrate both lead and concrete if the material in the path of the waves isn’t thick enough.