X-ray phosphors with low afterglow

Abstract

In europium-activated alkaline earth mixed halide x-ray phosphor compositions the addition of minor amounts of yttrium significantly reduces afterglow or persistance. A syngeristic effect upon the reduction of afterglow is observed when both yttrium and lithium additives are both included. Additions of other rare earths and alkali metals are not effective to reduce afterglow. The effective amount of Y is from about 0.001 to about 0.1 moles of yttrium per mole of host. When lithium is used in conjunction with yttrium, about 0.001 to about 0.1 moles of lithium per mole of host is used.

Dependencies are inferred from the claim text.