PURPOSE: To provide a high-sensitive photomultiplier capable of effectively utilizing light entered in a light incident window.
CONSTITUTION: In a head-on type photomultiplier in which one side end surface of a translucent glass bulb 1 is adopted as a light incident window 2 and a photoelectric surface 3 is formed on the inner side of this light incident window 2, a side part photoelectric surface 10 is formed on the whole periphery of the light incident window side part of the inner surface of a glass bulb side wall 8. Also a reflecting film 14 is formed on the whole periphery of a glass bulb side wall outer surface so as to surround the whole of the side part photoelectric surface 10. Consequently even light L', entered in an oblique outer direction to the light incident window peripheral part, is reflected in the inner direction by a reflecting film 14 to reach the side part photoelectric surface 10, and is converted into a photoelectron to be detected by a positive electrode 7.
OSUGI NOBUYUKI
TOTSUKA TOSHIHARU
