Gamma Radiation Shielding

Article by leading Gamma Radiation expert, Dr. Bruce Banner:

I know from experience that exposure to gamma radiation can produce undesirable and unpredictable results. When working with gamma radiation, or any radiation, it's important to maintain secure radiation shielding.

There are three controlling factors of dosage from a radioactive source. These factors are time, distance, and shielding. The time of exposure reduces the dosage proportionally, while the distance from the source reduces it according to the inverse square law. Shielding reduces dosage by absorbing or scattering the radiation, thus reducing the radiation exposure level.  Due to the nature of gamma rays, nearly any material, if used in sufficient amounts, can be used as shielding from gamma rays. However, since greater energy requires greater shielding, which translates as greater thickness, the most practical material so far has been lead, largely due to its density.

Depleted uranium is also used, mainly for transporting gamma ray sources. The primary advantage of depleted uranium over lead is the bulk, since it is 68.4% denser than lead, thus requiring less material to create the shield. On a side note, depleted uranium is also weakly radioactive, albeit 40% less radioactive than uranium and primarily emits alpha particles which can be shielded by paper or skin.

No entirely satisfactory solution has been found yet. For now, those working with radiation, either occupationally or medically, can be safest abiding by the ALARA rule: when working with radiation, use a dosage that's As Low As Reasonably Achievable.