Abstract: Discharge tube apparatus includes an outer containing vessel and a structure comprising for example five metal cylinders located co-axially within it. Each of the metal cylinders includes projecting spacers on its outer surface which serve to space it from adjacent ones. Such a structure is thermally insulating and may be arranged to enable a large temperature difference to be maintained between the interior of the discharge tube and the outer containing vessel. In other embodiments, a plurality of structures are included disposed along the axis of the tube. Also, dispenser segments for dispensing part of the active medium of a metal vapor laser may be included and arranged to shield vulnerable surfaces in the tube from direct exposure to the discharge.

Abstract: A metal vapor discharge tube includes cylindrical dispenser blocks of sintered tungsten which are porous and support metal whose vapor is to form at least part of the active medium of the tube. Thus, the dispenser blocks retain the metal, holding it in position when in its solid and liquid states. Heat shields serve to retain heat within the envelope of the discharge tube and uniformly heat the cylinders.

Abstract: The invention provides a laser arrangement including in its discharge circuit a switching thyratron which is capable of conduction normally in one direction and protectively in the reverse direction. The thyratron has an anode formed as a hollow body which is adapted to retain plasma generated during a pulse of forward conduction so that the anode is provided to act as a cathode permitting protective reversal of the thyratron when this is subject to reversal of voltage.

Abstract: The invention provides a laser arrangement including in its discharge circuit a switching thyratron which is capable of conduction normally in one direction and protectively in the reverse direction. The thyratron has an anode formed as a hollow body which is adapted to retain plasma generated during a pulse of forward conduction so that the anode is provided to act as a cathode permitting protective reversal of the thyratron when this is subject to reversal of voltage.

Abstract: The invention provides a glass enveloped thyratron having an anode carried by an anode pin extending through a glass neck in the thyratron envelope and forming a pant leg. The anode is surrounded by a screening box operated at cathode potential which has a back plate with a tubular portion extending away from the anode into the interior of said pant leg to surround said anode pin. The outer surface of the extremity of the pant leg is flared outwardly adjacent the back plate into engagement with a mounting collar secured to the rear of the back plate. The tubular portion of the back plate extends within the pant leg for a distance substantially greater than the extent to which the pant leg is enclosed by the mounting collar.

Abstract: This invention concerns gas filled thyratrons and is concerned with preventing the formation of arc spots on the grid when the thyratron is operated in a grounded grid mode. The thyratron provided has a grid consisting of three apertured baffle electrodes which are electrically united and occur in sequence in the cathode to anode path of the thyratron. The baffle electrodes on the cathode side of the final baffle electrode forms at least one re-entrant hollow cathode and conductive gauze covered apertures in the baffle electrodes on the cathode side of the final baffle electrode are staggered relative to apertures in the final baffle electrode.