Which radioactive isotopes are commonly used in XRF testing for lead?

The option that identifies Cobalt-57 and Cadmium-109 as the radioactive isotopes commonly used in XRF (X-ray fluorescence) testing for lead is accurate because these isotopes emit X-rays that can interact with lead materials. In XRF testing, a primary source of radiation is used to excite the atoms in the sample being analyzed, and the secondary X-rays emitted are characteristic of the elements present in the sample.

Cobalt-57, for example, emits X-rays at specific energies which are ideal for effectively detecting lead in various materials. Similarly, Cadmium-109 is used for its ability to emit X-rays in the range that is particularly sensitive to lead detection, allowing for accurate quantification of lead content.

This accuracy is crucial in environments where lead presence poses health risks, such as in buildings, paint, and plumbing materials. Utilizing these isotopes ensures that the XRF testing can reliably measure lead concentrations, thereby contributing to safety assessments and regulatory compliance efforts.