What minimum type of shielding is needed to stop gamma radiation?

Answer 1

Gamma radiation has in principle infinite range. So it is not possible to block it completely. But it is possible to attenuate it to certain level. The thickness of concrete needed depends on gamma photons energy and concrete properties.

Answer 2

Shielding from gamma rays requires large amounts of mass. They are better absorbed by materials with high atomic numbers density, although neither effect is important compared to the total mass/area in the path of the gamma ray. For this reason, a lead shield is 25% more effective a gamma shield than an equal mass of another shielding material such as aluminum, concrete, or soil. Lead's major advantage, however, is its density.

The higher the energy of the gamma rays, the thicker the shielding required. Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL). For example gamma rays that require 1 cm (0.4″) of lead to reduce their intensity by 50% will also have their intensity reduced in half by 4.1 cm of granite rock, 6 cm (2½″) of concrete, or 9 cm (3½″) of packed soil. However, the mass of this much concrete or soil is only 20-30% larger than that of this amount of lead. Depleted uranium is used for shielding in portable gamma ray sources, but again the savings in weight over lead is modest, the main effect being reducing the shielding bulk.

Answer 3

It is very dense so it absorbs many of the rays. It will not block gamma rays completely. Its an exponential process.

Answer 4

Lead absorb X-rays. Lead is a heavy metal.

Answer 5

88mm of lead

Answer 6

A few millimetres of lead.

Answer 7

Lead