What is the primary form of shielding used by modern exposure devices?

The primary form of shielding used by modern exposure devices is lead. Lead is a highly effective material for shielding against radiation, particularly gamma rays and X-rays. Its high density and atomic number make it particularly suitable for absorbing and attenuating these types of radiation. This effectiveness is crucial in ensuring the safety of personnel working near radiation sources.

Modern exposure devices, which often incorporate radioactive isotopes for industrial radiography, rely on lead for shielding to minimize radiation exposure to workers and the surrounding environment. The use of lead also allows for relatively compact designs in exposure devices, as smaller amounts of lead can achieve the necessary thickness to provide adequate protection.

Other materials, like concrete and steel, have their applications in radiation shielding but are less common for the specific use of exposure devices. Depleted uranium, while it has applications in some specialized contexts (like military armor), is not typically used in exposure devices due to its associated health risks and regulatory considerations.