High efficiency fluorescent screen pair for use in low energy X radiation imaging.

摘要

Pair of front and back intensifying screens are each formed of a fluorescent layer which is exposed to X-rays of energy mainly below 40 keV, the front screen having modulation transfer factors greater than those of curve A capable of attenuating by 20-60% a reference X-ray exposure produced by an Mo target tube operated at 28 kVp with a three-phase supply, the X-ray exposure passing through 0.3mm Mo and 4.5cm. poly-methyl-methacrylate to reach the layer mounted 25cm. from an Mo anode of the target tube, attenuation being measured 50cm. beyond the layer. The back screen has modulation transfer factors greater than those of curve B and attenuates at least 60% of the X-rays received from the front screen when the reference exposure is repeated with both screens present.