HARP: A Very Sensitive Camera Tube Using Avalanche Multiplication in an a-Se Photoconductive Target

摘要

It was found that an experimental camera tube with an amorphous photoconductive target of selenium exhibits high sensitivity with a quantum efficiency in excess of unity at an applied electric field of more than 80 million V/m. The results from avalanche multiplication. A selenium target for practical use was doped with impurities to prevent the appearance of white blemishes in the video image. A camera tube with the target, which is called a HARP tube, is about 10 times as sensitive as a conventional camera tube, without any degradation of picture quality, i.e. with good dark current, lag characteristics, resolution, and noise performance. The HARP tube thus ensures both high sensitivity and excellent picture quality which cannot be achieved by conventional image devices, and it offers a greatly improved performance not only in HDTV camera, but also in cameras for other television systems.