Support and focus structure for photomultiplier

Claim 1

A photomultiplier comprising, in combination: a. a light transmissive evacuated glass envelope having an inner and outer wall surface, b. a stem portion sealed to one end of the glass envelope, the stem portion including a plurality of lead-in pins extending within said envelope, c. an electrode assembly, within the envelope, including a plurality of spaced-apart electrodes including: a photocathode, at least one dynode, and an anode; said electrodes being secured longitudinally, at their opposing ends, between two substantially parallel support plates of insulating material; various ones of the electrodes being interconnected by lead wires to respective ones of said lead-in pins, d. a plurality of spring members each having a plurality of resilient portions fixably constrained between the inner wall surface of said glass envelope and portions of the electrode assembly which are electrically isolated from various ones of the electrodes, to retain the electrode assembly in substantially fixed mechanically aligned relation with the inner wall surface of said envelope, and to substantially electrically isolate the electrodes of the electrode assembly in spaced-apart relation from the inner wall surface of said envelope, and e. a plurality of electron focusing electrodes, interposed between said support plates and ends of the electrodes of said assembly securred to said support plate; said focusing electrodes comprising conductive metallization regions on said support plates, overlying interelectrode regions between respective ones of the electrodes, through which electrons may be accelerated, whereby electrons may be substantially prevented from impinging upon said support plates.