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24 May 2012

Answer to Question #1286 Submitted to "Ask the Experts"

Category: Radiation Basics

The following question was answered by an expert in the appropriate field:

What are the properties of lead that make it our material of choice for radiation protection?

Lead is often the material of choice for x and gamma radiation for a number of reasons. Its high atomic number and high density make it a very effective absorber of photons, particularly at energies of several hundred keV and below. (In this energy range, photoelectric absorption is the most important physical interaction that takes place.) Few available materials match its shielding ability per g cm^-2. As a result, lead shields are considerably thinner and also lighter than ones made of other common materials for the same dose-rate reduction. Lead is relatively cheap. It can be fashioned into sheets, containers, bricks, aprons, and other convenient forms for various applications. Whereas lead is the "material of choice" for photons, it does not play such a role for other types of radiation. For beta shielding one generally employs a material of low atomic number to minimize bremsstrahlung production. For fast neutrons, materials of low atomic number are also the most effective (for other reasons). James Turner, CHP

Answer posted on 19 October 2001. The information and material posted on this website is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Website. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.