US 5,057,740 AGranted

Photoemissive trigger for backlighted thyratron switches

AssigneeIntegrated Applied Physics Inc.

InventorGeorge F. Kirkman-Amemiya

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Abstract

Provided is a means for triggering certain high voltage electronic, gas discharge switches that are a novel type of high power thyratron. Triggering of switches of the so-called "backlighted thyratron" type (a type of cold cathode thyratron) is enhanced by the inclusion of a very small, photoemissive cathode, separate and isolated from the main switch electrodes, to initiate the triggering discharge. The trigger cathode is protected from destruction by the main discharge current through the switch by mechanically and electrically isolating it from further participation in the discharge once the triggering process has been initiated. Alternatively, photosensitive material is coated on the backside of one of the main switch electrodes. A light source located externally of the switch directs light through a sealed aperture into the interior of the switch where it is incident on the photosensitive material generating electrons which in turn trigger the main switch discharge.

Claims14

Dependent claims

A high power electronic backlighted thyratron switch, comprising:

an evacuated envelope back filled with a selected elemental gas at a predetermined pressure;
an anode located within the envelope having a first aperture;
a cathode located within the envelope at a predetermined distance from the anode and having a second aperture, said anode and cathode being disposed opposite each other, with said first and second apertures in alignment;
means for supplying electrical power to the anode and cathode to provide main discharge current therebetween;
light source means located externally of the envelope, said envelope having a third aperture formed therein;
a window sealed in said third aperture and aligned with said light source means to permit light from said light source means to enter said envelope;
photosensitive means located within the envelope such that light is incident thereon to cause the production of electrons therefrom and their injection through one of said first and second apertures into the space between said anode and cathode to initiate a main discharge;
and
a sweep electrode disposed adjacent said photosensitive means to prevent said main discharge from impinging directly on said photosensitive means.

6 more elements

Dependencies are inferred from the claim text.