Answer to Question #1318 Submitted to "Ask the Experts"

Q

Can beta particles pass through 2mm of lead and can lead be used to shield beta particles?

A

To answer the question directly, 2 mm of lead will stop beta particles with an impinging energy of about 4 MeV or less (Radiological Health Handbook 1970)—however, the effectiveness of shielding would also need to consider x-ray production. The linear penetration ability for all types of particles depends on the particle type and energy as well as the type of material. Beta particles lose an appreciable amount of their energy via bremstrahlung radiation within a shield—with the amount released being strongly correlated with the atomic number of the absorbing media. This means that high-atomic-number shields, such as lead, will act to generate significantly more x rays from beta-emitting radionuclides than do low-atomic-number materials such as plastics. While lead would not be an ideal selection for a light-weight beta shield, if it were thick enough then it would also be an effective shield for the x rays produced.

Robert L. Coleman
Oak Ridge National Laboratory

Reference
Radiological Health Handbook. US Department of Health, Education, and Welfare, Public Health Service, Food and Drug Administration, Bureau of Radiological Health, Rockville, MD. Washington, DC: U.S. Government Printing Office; Jan 1970.