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Lightweight radiation-proof fabric unveiled 09:58 15 November 02 Exclusive from New Scientist Print Edition
The world's first lightweight radiation-proof fabric has been developed by a US company.
Called Demron, its potential applications range from lightweight full-body suits - which would allow the wearer to move unencumbered in high-radiation areas - to protective tents and radiation-proof linings for aircraft and spacecraft.
Traditional shielding relies on the presence of heavy metals, such as lead. But Demron is based on a polymer that mimics some of the electronic properties of these heavy metals, says John Hefler of Radiation Shield Technologies, the company in Miami, Florida, that is developing the material.
Its inventors claim that it provides protection comparable to the nuclear industry's standard-issue lead vest, blocking alpha, beta, gamma radiation and X-rays. Traditional protective clothing only protects against alpha radiation.
Heavy metals have large atoms, and so have large numbers of electrons. When the particles that make up alpha and beta radiation collide with these electrons, they slow down, and are absorbed by the material. The helium nuclei that make up alpha radiation have so little energy that almost any physical barrier can stop them. Gamma rays and X-rays are highly penetrating forms of electromagnetic radiation, which can only be stopped if the electrons in a shield's material can absorb enough of their energy.
Demron consists of a polyethylene and PVC-based polymer fused between two layers of a woven fabric. The polymer molecule has been designed so that incoming radiation will meet a large electron cloud, which will deflect or absorbed it.
"The molecules are lined up to give the illusion of the presence of large atoms," says Hefler. The electrons are capable of deflecting beta radiation or absorbing the energy of alpha radiation and X-rays.
The nuclear industry is still reserving judgement on the new material. "The potential usefulness of the fabric will depend on the level of protection it offers against gamma and X-rays, and how it reacts and degrades when subjected to radiation," says Janine Claber of British Nuclear Fuels.
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