"COR-RA" (colorless atomic oxygen resistant — radiation shield) is the name of a transparent polymeric material filled with x-ray-absorbing salts of lead, bismuth, cesium, and thorium. COR-RA is suitable for use in shielding personnel against bremsstrahlung radiation from electron-beam welding and industrial and medical x-ray equipment. In comparison with lead- foil and leaded- glass shields that give equivalent protection against x-rays (see table), COR-RA shields are mechanically more durable.
COR-RA absorbs not only x-rays but also neutrons and g rays without adverse effects on optical or mechanical performance. The formulation of COR-RA with the most favorable mechanical-durability and optical properties contains 22 weight percent of bismuth to absorb x-rays, plus 45 atomic percent hydrogen for shielding against neutrons.
This work was done by David Edwards of Marshall Space Flight Center and John Lennhoff and George Harris of Triton Systems, Inc. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Materials category. MFS-31371.