Photomultiplier

摘要

An electron lens electrode (5) for guiding photoelectrons emitted from a photocathode (2) to an electron multiplier section is arranged between the photocathode and the light-incident portion of a sealed container, and an opening (15a) is formed at a portion of the electron lens electrode opposing the light-incident portion. Incident light reaches the photocathode through the opening without being scattered or absorbed at all. The transmittance of light incident on a photomultiplier is improved, and the output waveform is uniformed, resulting in an improved S/N ratio.