GB725685A - Improvements in or relating to cold-cathode gas-discharge tubes - Google Patents

Abstract

725,685. Cold-cathode tubes. HIVAC, Ltd. Feb. 10, 1953, No. 3734/53. Class 39 (1). The recovery time of a coldcathode gas discharge tube having a filling consisting of a gas or a combination of gases of Group O of the periodic system is reduced by adding to the filling a small percentage, preferably not more than 5 per cent, of nitrogen for quenching purposes and providing the cathode with an emissive coating of a mixture of aluminium and magnesium. The trigger tube shown comprises a cylindrical cathode 18 and trigger electrode 20 supported respectively by wires 19 and 21 sealed into a glass disc 12 supported from the pinch 16 by a stem 11. A rod anode 14 is supported in a hollow 13 in the stem 11 by a lead-in wire 15. The inner surface of the cathode 18 is coated with a mixture of 55 parts of aluminium to 45 parts of magnesium, and the outer surface is preferably calorized or coated with alumina to increase the work function. The trigger electrode support wire 21 and other supporting or connecting wires within the envelope are also treated or coated to have a high work function. The gas filling is neon with 3 per cent added nitrogen at a pressure of 40 mm. of mercury. Although neon is preferred as the principal gas, other gases of Group O of the periodic system may be employed, more particularly argon or helium.