To provide a photomultiplier tube achieving great improvement of response time characteristics with a structure capable of producing a large volume.
The photomultiplier tube is provided with an electron multiplier (500) for carrying out cascade multiplication of secondary electron emitted in response to incidence of photoelectron. The electron multiplier (500) is provided with a structure for retaining at least dynode groups of two systems arranged in a state with a tube axis (AX) pinched in between of a closed vessel (100) with the electron multiplier (500) stored. Especially, first dynodes (DY1) each belonging to the dynode groups of two systems, are arranged in opposition with a back face opposing to a secondary electron emission face pinching the tube axis (AX). In this alignment, since the first dynode (DY1) itself is placed near the tube axis (AX), collection efficiency of photoelectron reaching a periphery of the first dynode (DY1) is remarkably improved.
KIMURA SUENORI
Shiro Terasaki
Satoru Ishida
Next Patent: PHOTOMULTIPLIER TUBE