GB755928A - Improvements in or relating to cold cathode gas discharge tubes - Google Patents

Abstract

755,928. Multi-gap cold-cathode tubes. MULLARD RADIO VALVE CO., Ltd. July 8, 1953 [July 21, 1952], No. 18364/52. Class 39 (1). [Also in Group XIX] A cold cathode gas-discharge counting tube, Fig. 4, comprises a main cathode 20 having extended portions 21, 22 and 23 and a transfer cathode 24 having extended portions 25, 26 and 27, arranged in interdigitated formation opposite a common anode (not shown). A screen 30 is arranged between the anode and the cathodes so as to lie at the upper face of the cathode fall zone and is provided with a series of perforations 32, each having a slotted portion 32a and a circular portion 32b. A discharge initiated in a slotted portion of a perforation will move automatically to the circular portion, thus ensuring a unidirectional movement of the discharge. As an alternative to the interdigitated main and transfer cathodes, a series of individual main and transfer cathodes may be provided. The tube is connected in a circuit of the form shown in Fig. 3 wherein the main cathodes 9 and 11 are connected to earth and the transfer cathodes 10 and 12 are connected to a source of negative-going pulses 19. The anode 1 and screen 5 are connected through respective resistors 17 and 18 to sources of positive potential. A discharge at a main cathode is stepped to the next main cathode along the array to the right, as determined by the shape of the perforations in the screen, in response to each pulse applied to the transfer cathodes. Bi-directional stepping of the discharge to allow addition and subtraction is provided by the construction shown in Fig. 7 which comprises main cathodes 50, 51 and 52 arranged opposite perforations 40, 41 and 42 in a screen 30, each perforation comprising a circular portion and two slotted portions arranged at an angle. A first set of transfer cathodes 53, 55 and 57 is arranged opposite perforations 43, 45 and 47 of the keyhole form previously described, and a second set of transfer cathodes 54, 56 and 58 is arranged opposite perforations 44, 46 and 48 of similar form but having the slotted portions extending in the opposite direction. A discharge at a main cathode is transferred to the next main cathode to the right by applying a pulse to the first set of odd numbered transfer cathodes, or to the next cathode to the left by applying a pulse to the second set of even numbered transfer cathodes. The cathodes in either of the arrangements may be arranged to lie in a cylindrical surface either surrounding or surrounded by a cylindrical screen and anode. Reference has been directed by the Comptroller to Specification 696,109.