Vidicon Type X-ray Imaging Sensor Using a Highly Sensitive Cadmium Telluride Photoconductive Film.

A one-inch X-ray vidicon (imaging camera tube) with a polycrystalline cadmium telluride (CdTe) photoconductive target has been developed. This vidicon has a 10.5μm thick CdTe layer deposited by RF sputtering and can attain an X-ray signal current of about 200 nA/cm2 for 2.58 mC/kg/min (10R/ min). This value is higher than the 45 nA/cm2 of conventional PbO X-ray vidicons. The dark current is about 5 nA/cm2 at a target voltage of 35 V at room temperature. The resolution of the device exceeds 251p/mm (20μm). In addition, by using a sputtering technique which can obtain large and uniform film, simultaneous deposition of many conventional and large vidion targets can easily be performed.