Radiation Shield Technologies (RST) usa based company, had developed the first lightweight radiation-proof fabric in the world. The fabric is claimed to provide protection comparable to the nuclear industry's standard-issue lead vest, which blocks alpha, beta, gamma radiation and X-rays. However, not as heavy as a lead one.The new fabric, named "Demron", is made up of a polyethylene and PVC-based polymer embedded between two layers of an ordinary woven fabric.

Non-Lead Radiation Shields and Nano Shields

As you know, production of environmentally-friendly lead-free radiation shields with less weight compared to conventional lead-based shields is a challenging issue in diagnostic radiology and nuclear medicine. A couple of years ago, we produced some cost-effective lead-free flexible radiation shields which offered effective radiation protection in a diagnostic energy range. We suggested that these environmentally-friendly shield (tungsten-tin-filled polymers with appropriate radiation attenuation properties) may replace the traditional lead-based shielding garments. Please check the full paper at JBPE Journal web site:

http://www.jbpe.org/Journal_OJS/JBPE/index.php/jbpe/article/view/4

Recently, we have focused on the radiation shielding properties of nano-sized shielding materials. Flexible sheets of WO3 in a poly vinyl chloride (EPVC) polymeric matrix were produced in our laboratory. In this experiment, WO3 nanoparticles with grain size ranged 20-100 nm (+99% purity) and WO3 micro particles with average particle size

Plastic sheet with W in it might work for low energy photons but for higher energy photons it will not work well. For Co-60 you need about 10 cm of lead to stop about 99% of the gamma rays. An alternative to 10 cm of lead is 1 m of water.

For high to moderate energy gamma sources such as Co-60 the main way in which gamma rays interact with matter is the Compton effect. Thus things with a high electron density such as high Z elements are great at stopping the gamma rays. At higher energies processes such as photonuclear and pair production become more important as ways of stopping gamma photons, both of these processes are more likely to occur at high Z nuclei.

So the best gamma shields will be things like DU and lead, their properties can be imporved by mixing them with lower Z solids such as concrete or by putting layers of Al over the surface, this is to stop the high Z solid being a source of photoelectrons and Compton electrons which can make the dose rate higher under some conditions.

I would be very careful of any claims that nano particles of high Z solids have special extra good abilites to stop radiation, bear in mind that any new solid has to be better than concrete blocks which contain steel shot or concrete blocks made of heavy concrete containing Ba in place of some of the Ca.

One advantage of using nano WO3 is that it is less likely to make a solid which has a gap between the WO3 spheres which allows the X-rays through, I think in some ways that a mixture of different sized spheres would be best as it will give a better packing density.