DEMRON might sound like the sort of planet that Star Trek鈥檚 Jean-Luc Picard might beam down to, but it鈥檚 actually the world鈥檚 first lightweight radiation-proof fabric 鈥� something that would come in handy to shield the Enterprise from cosmic rays.
Traditional shielding relies on the presence of heavy metals, such as lead. But not Demron. Instead it 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.
Demron鈥檚 potential applications range from lightweight full-body suits 鈥� that would allow the wearer to move unencumbered in high-radiation areas 鈥� to protective tents and radiation-proof linings for aircraft and spacecraft. Its inventors claim that it provides protection comparable to the nuclear industry鈥檚 standard-issue lead vest, blocking alpha, beta, gamma radiation and X-rays. Traditional protective clothing only protects against alpha radiation.
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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鈥檚 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. 鈥淭he molecules are lined up to give the illusion of the presence of large atoms,鈥� 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. 鈥淭he 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,鈥� says Janine Claber of British Nuclear Fuels.