By: Chris Newman
When considering options for radiation shielding, the most important thing is to use materials with a high density. Lead and tungsten are the most common materials to shield gamma radiation, however, they both have different advantages.
Lead has numerous applications, but it’s mostly used in nuclear power, nuclear medicine, diagnostic imaging and non-destructive testing for radiation protection and shielding. It is one of the most versatile forms of shielding materials that is used to overcome common challenges such as limitations on space, price, and installation associated with designing and building radiation shielding. Compared to other shielding materials, lead is less expensive, easily available, and easy to process into finished radiation shielding products.
Lead is very effective at shielding x-ray and gamma radiation. Because of the density of lead, its high atomic number, and stable isotopes, lead is ideal for stopping gamma and x-ray radiation. For a gamma ray from a Colbalt-60 source, pure lead has a Half-Value Layer (HVL – the thickness of shielding required to reduce the level of radiation by 50%) of approximately 12.5 mm (0.49 in). A lead shield will be thinner than a steel (21.6 HVL) or concrete (60.5 HVL) shield of the same effectiveness in shielding a Co60 source. From an x-ray source with a peak voltage of 200 kV, the HVL of lead would be 0.52 mm (0.021 in).
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Tungsten has a density that is approximately 1.7 times higher than lead, therefore it provides a higher degree of shielding. It is a viable option for applications where lead is not a feasible option, including for size reduction, and maximizing weight in large or small cavities for radiation shielding. It is strong and highly customizable into precision components.
Tungsten is the preferred choice for medical and industrial settings that require radiation shielding since it uses less material than lead to provide the same level of absorption. An excellent material for shielding, tungsten guarantees minimum radiation exposure and ensures ALARA goals in the workplace. Machinability, radiographic density, strength, low toxicity, and heat resistance allow for superior design adaptability vs. other shielding materials.
You can learn more about the applications of tungsten here.
Difference Between Lead and Tungsten
There are several differences between lead and tungsten. Selecting the right radiation shielding option depends on the requirements of the project.
- Lead is less expensive than Tungsten
- Lead is more vulnerable because it is soft
- To prevent exposure, lead may need to be encapsulated or coated
- Lead can be cast while Tungsten cannot
- Less tungsten is required to provide a certain attenuation
From concept to finished product MarShield is the leader in the manufacturing and supply of radiation shielding products and materials in North America. You can find more information from the MarShield website or you can contact MarShield directly, and we will help you find the most appropriate radiation shielding solution for your organization.
MarShield Custom Radiation Shielding Products provides radiation shielding solutions for the Medical and Nuclear Industries and is a division of Mars Metal Company. Contact us today to discuss your unique radiation shielding needs!