Photomultiplier tube with improved light collection

Photomultiplier tubes with improved collection of incident radiation, especially from the periphery of the front face of the tube, and that more efficiently couple the collected radiation to the photocathode, and moreover have higher packing densities when assembled into arrays, resulting in enhanced imaging characteristics. The improvements in radiation collection and photomultiplier tube packing density are gained by a combination of several features including: tapering the edges of the faceplate so that the faceplate subtends an area as large or larger than any other cross-sectional area of the photomultiplier tube; forming the junction between the faceplate and metal tube on the underside of the faceplate, and in such a manner as to avoid obscuring the optical path between the incident radiation and photocathode; and utilizing the tapered edge of the faceplate as a reflector to couple radiation incident on the periphery of the faceplate to the photocathode.