Patent GB-380429-A (GB)
Title: Method for the production and control of electronic streams
IPC: H01J21/08
Filed: 1931-03-10
Abstract: 380,429. Discharge apparatus. HARRIES, J. H. O., Shirley, Old Road, Frinton-on-Sea. March 10, 1931, No. 7412. [Classes 39 (i) and 40 .(v).] Relates to a discharge tube having an anode, a cathode, one or more positively charged accelerating electrodes with or without one or more decelerating electrodes, and operating with a saturated anode current whether the current between the cathode and the nearest accelerating electrode is saturated or not ; the distance between an accelerating electrode and the anode or other electrode at a positive potential is such that there is a negative potential gradient at a point between those electrodes, so that no secondary emission passes from the anode &c. to the accelerating electrode when the anode &c. potential is less than that of the accelerating electrode ; further, the distance between the accelerating electrode and the anode &c. is such that the rate of change of the " distance curve " is positive or not more than slightly negative, the " distance curve being the curve relating the distance and potential difference between those electrodes at which the current becomes saturated. The tubes described are of the type according to Specification 328,680, [Class 39 (i), Electric lamps, Arc &c.], in which a stream of electrons having a long path is deflected, but the invention is applicable to tubes in which the path is shorter, and the resistance or current density is controlled. As shown in Fig. 1, the cathode 2 consists of a flat spiral surrounded by a hood 3, the anode 5 is mounted on rods 10 connected by glass rods 14 so as to be slidably adjustable on glass rods 6 during manufacture or use, and the accelerating electrode 4 consists of a mesh. Fig. 6 shows at a the curve between the anode voltage Ea and the anode current I, and at g the curve between the voltage on the accelerating electrode 4 and the current to that electrode ; current passes entirely to the accelerating electrode at low anode voltages and the anode current increases rapidly to saturation at an initial anode voltage Eb referred to as the " breakdown voltage." In Fig. 7 the curve shows the " breakdown voltage" Eb plotted against the distance d between the anode and the accelerating electrode ; the distance d is preferably chosen at the lowest value of Eb shown on the curve. In the tube shown in Fig. 18 for use as a frequency multiplier of the type described in Specification 328,680, an additional accelerating electrode or record 17 and deflecting plates 20 are interposed between the accelerating electrode 4 and the anode 5. The record 17 consists of a disc with slots 16, Fig. 23, covered by a mesh 18. Variations of potential in the saturated part of the tube may be transferred to the unsaturated part. Thus in the relay arrangement shown in Fig. 10, the anode 5 is connected with the accelerating electrode 4 through a resistance R of such a value that variations of potential on the anode are transferred to the electrode 4. The anode acts as the target electrode referred to in Specification 328,680 and is connected with the battery 11 through a load impedance 15. In a modification, the resistance is replaced by a condenser, and the electrode 4 is connected with an intermediate point of the battery through a choking coil. In the arrangement shown in Fig. 15, two accelerating electrodes G<1>, G<2> are interposed between the cathode 2 and anode 5, and a decelerating grid electrode G<3>, connected with the cathode, is mounted near the electrode G<2> so as to assist in the formation of the negative potential gradient between the electrodes G<1>, G<2> and prevent the passage of secondary electrons from G<2> to G<1>. In a modification of this arrangement, the decelerating electrode is mounted close to the anode. The electron stream may be deflected by a magnetic field. Specification 366,053 also is referred to.