Photomultiplier with lens element

摘要

A photomultiplier includes a photocathode (3); an electron multiplier section (60) for cascade-multiplying photoelectrons emitted from the photocathode (3); a faceplate (2) provided with the photocathode (3); a metal housing (1) accommodating the photocathode (3) and the electron multiplier section (60); and a structure disposed on the faceplate (2) for increasing the effective light entrance region of the faceplate (2). In a preferred embodiment the subject structure includes a lens element (30) attached to the faceplate for increasing the effective light entrance region of the faceplate (2). In order to improve the optical coupling efficiency, either the faceplate (2), or the lens element (30), or both the faceplate (2) and the lens element (30) may further include a protrusion.