Gas laser discharge tube having insulator shields

Claim 1

A GAS LASER APPARATUS INCLUDING MEANS FORMING AN ELONGATED TUBULAR GAS TIGHT ENVELOPE FOR CONTAINING A GAS LASER DISCHARGE COLUMN WITHIN A GAS FILL INSIDE OF SAID ENVELOPE, MEANS FORMING A PAIR OF ELECTRODES AXIALLY SPACED APART OF SAID ELENGATED TUBULAR ENVELOPE ONE OF SAID ELECTRODES ADAPTED TO OPERATE AT ANODE VOLTAGE AND THE OTHER ADAPTED TO OPERATE IN USE AT A VOLTAGE NEGATIVE WITH RESPECT TO THE ANODE VOLTAGE, FOR EXCITING THE GAS LASER DISCHARGE COLUMN IN THE REGION THEREBETWEEN, MEANS FORMING A DIELECTRIC INSULATOR ASSEMBLY DISPOSED INTERMEDIATE SAID PAIR OF ELECTRODES AND DEFINING A PORTION OF SAID TUBULAR ENVELOPE, MENAS FORMING A METAL -TO-DIELECTRIC GAS TIGHT JOINT BETWEEN SAID INSULATOR AND A METALLIC PORTION OF SAID ENVELOPE WHICH ENVELOPE PORTION IS OPERATED IN USE AT A POTENTIAL VEGATIVE WITH REPECT TO THE ANODE VOLTAGE, AND MEANS FORMING A SHIELD DISPOSED WITHIN SAID ENVELOPE ADJACENT SAID METAL-TO-DIELECTRIC JOINT FOR SHIELDING SAID JOINT FROM BOMBARDMENT BY IONS ORIGINATING IN THE LASER DISCHARGE COLUMN BY RECEIVING SUCH IONS INCIDENT THEREON, AND SAID SHIELD ALSO SERVING TO SHIELD AT LEAST A PORTION OF THE LENGTH OF THE INSIDE SUFACE OF SAID INSULATOR FROM SPUTTERED METALLIC PARTICLES SPUTTERED OFF ION BOMBARDED SURFACES WITHIN SAID TUBULAR ENVELOPE, WHEREBY THE OPERATING LIFE OF THE LASER APPARATUS IS EXTENDED AS COMPARED TO SIMILAR LASER APPARATUS WITHOUT SAID SHIELD MEANS.