Lightweight composite metal foams could prove to make all the difference when it comes to x-ray and gamma ray shieldingand neutron radiation protectionas they can absorb the energy created during high-impact collisions, says study. This study was published in the Radiation Physics and Chemistry Journal and was authored by researchers from NC State. The work was also supported by the Nuclear Energy University Program grant offered by DOE’s Office of Nuclear Energy.
“There’s an opportunity to use composite metal foam to develop safer systems for transporting nuclear waste, more efficient designs for spacecraft and nuclear structures, and new shielding for use in CT scanners,” says AfsanehRabiei, one of the authors of this study, professor of aerospace engineering at NC State. This means that metal foams could be extremely useful for space exploration applications, medical technology and nuclear safety.
This lightweight metal foam was first built to be used in military and transportation applications, but the authors also wanted to determine whether it could be helpful in space exploration applications and nuclear radiationprotection, and to examine whether this metal foam could protect against high impact, offer structural support and provide radiation shielding against different types of radiation.
To examine its use, the study conducted several tests to examine the foam’s effectiveness at gamma ray shielding, x-ray shielding and radiation protection. This was then compared to the performance of materials that are currently being used in all kinds of shielding applications. The comparison proved that while each sample had the same weight, it varied in terms of volume.
A composite material known as high-Z steel-steel was found to be the most effective in offering protection against all three forms of radiation. This metal is mostly comprises of stainless steel, but it also contains small quantities of tungsten. The major difference is that its structure was modified so that the composite foam which included tungsten wasn’t denser than metal foams made using stainless steel only.
The shielding performance of this new material was then tested against different types of gamma rays as gamma rays can have different energies depending on the source material. For example, barium emits low energy gamma rays while cobalt or cesium emits higher-energy rays.
The study went on to show that high-Z steel-steelfoam was on par with most bulk materials at blocking high-energy gamma rays, but it was far better than most, including bulk steel, in blocking out low-energy gamma rays. The material also outshone others when it came to neutron radiation protection and x-ray shielding.
This foam is non-toxic which makes it easy to recycle and manufacture. It can also act as a viable candidate for nuclear structural applications because of its thermal and mechanical properties, and its capability to absorb energy. Researchers are now working on modifying the composition of this metal foam to make it a more effective shield against x-rays. Rabiei says that early results are extremely promising.