Abstract: A spectral filter used in conjunction with a lutetium-based scintillation material in a radiation detector is in imaging systems. The spectral filter operates to block at least a portion, but preferably substantially all, of an undesired infrared afterglow which results from ytterbium impurities in the lutetium-based scintillation material.

Abstract: A light-emitting device comprising a UV-diode with a primary emission of 300 nm.ltoreq..lambda..ltoreq.370 nm and a phosphor layer including a combination of a blue-emitting phosphor having an emission band, with 430 nm.ltoreq..lambda..ltoreq.490 nm, a green-emitting phosphor having an emission band, with 520 nm.ltoreq..lambda..ltoreq.570 nm and a red-emitting phosphor having an emission band, with 590 nm.ltoreq..lambda..ltoreq.630 nm, emits high-quality white light. The color-rendering index CRI is approximately 90 at a color temperature of 4000 K. The color rendition depends only on the composition of the three phosphors, not on the relation between converted and non-converted light, and hence can be readily controlled and regulated.