Research from North Carolina State University devised lightweight composite metal foams which can effectively block X-rays, gamma rays and neutron radiation by absorbing the nuclear radiation and energy that can provide clues to make bunkers and vests to safeguard from future nuclear attacks.
Useful and most sought-after for use in nuclear safety, space exploration and medical technology applications, the lightweight high-Z foam was much better than bulk materials – even bulk steel – at blocking low-energy gamma rays, X-rays, but was not quite as effective as lead.
“This work means 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 Afsaneh Rabiei, a professor of mechanical and aerospace engineering at NC State and corresponding author of a paper.
It was first developed for use in transportation and military applications but during their application study, researchers found that the foam could be used for nuclear or space exploration applications as well.
Rabiel and her colleagues compared the material’s performance to the performance of bulk materials that are currently used with samples of the same “areal” density – meaning that each sample had the same weight, but varied in volume.
The most effective composite metal foam against all three forms of radiation is called “high-Z steel-steel” that was made up of stainless steel with traces of tungsten that was not denser than stainless steel.
The researchers found that the high-Z foam was comparable to bulk materials at blocking high-energy gamma rays, but was much better than bulk materials – even bulk steel – at blocking low-energy gamma rays.
However, the high-Z foam performed was not quite as effective as lead. “Our foams have the advantage of being non-toxic, which means that they are easier to manufacture and recycle. In addition, the extraordinary mechanical and thermal properties of composite metal foams, and their energy absorption capabilities, make the material a good candidate for various nuclear structural applications,” Rabiei says.
The paper, “Attenuation efficiency of X-ray and comparison to gamma ray and neutrons in composite metal foams,” is published in Radiation Physics and Chemistry.