US2790110A

US2790110A - Gaseous discharge device

Info

Publication number: US2790110A
Application number: US286997A
Authority: US
Inventors: Charles J Applegate
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-05-09
Filing date: 1952-05-09
Publication date: 1957-04-23
Anticipated expiration: 1974-04-23

Description

April 23, 1957 c. J. APPLE'GATE GASEOUS DISCHARGE DEVICE Filed May 9, 1952 COINCIOENCE DETECTOR 3 Sheets-Sheet 1 SIGN INDICATOR INVENTOR. Chqrles J. Applegute ATTORNEYS April 23, 1957 c. .1. APPLEGATE GASEOUS DISCHARGE DEVICE 3 Sheets-Sheet 2 Filed May 9, 1952 ENTOR. pp e Q INV Charles J,'A

I/ljI/l/I/lIl/lf F l G.- 2 z ATTORNEYS 7 April 23, 1957 c. J. APPLEGATE 2,790,110 GASEOUS DISCHARGE DEVICE I 3 Sheets-Sheet 5 Filed'lday 9, 1952 FIG.- 8

FIG. I'O.

FIG.- 9

INVENTOR.

. Charles J. Applegure ATTORNEYS United States Patent GASEOUS DISCHARGE DEVICE Charles J. Applegate, Boulder, Colo.

Application May 9, 1952, Serial No. 286,997 Claims. (or. 315-845 This invention relates to a gaseous discharge device in which an electrical discharge takes place betweenan anode and cathode in a low pressure gas, and more par ticula'rly to such a device which embodies a reversible characteristic which will permit its discharge to move to either of two anodes associated with the cathode One of the objects of my invention is to produce an improved gaseous electric discharge device embodying a single cathode and two anodes so constructed and associated that by controlling the voltage applied to the anodes, the discharge can be switched from and to the other anode, yet remain on the cathode.

Still a further object is to construct a gaseous electric discharge device in which two anodes are so associated with cathodes that by controlling the energization of the anodes, the discharge between one anode and a cathode can be transferred so that the discharge will step from one cathode to another in one direction upon each input pulse, With the said one anode only being energized, or the discharge between the other anode and the cathodes can be transferred so that the discharge will step from one cathode to another in the opposite direction upon each input pulse with the said other anode only being energized.

Another object of my invention is to so constructa gaseous electric discharge device having two anodes and a plurality of cathodes that a ring counter can be obtained in which addition and subtraction are both possible with the same input pulse.

Still another object is to produce an improved gaseous electric discharge device which can be employed as an elementary digital computer component capable of adding or subtracting an incoming pulse. 7

Yet another object is to produce an improved electronic counting system embodying gaseous electrical discharge devices, each so constructed as tobe capable of adding or subtracting counts repre'sented'by input impulses to the devices. V

A further object is to produce anew cathode; structure for association with anodes in a gaseous electrical discharge device. 7

Other objects of my invention will becomeap'parent from the following description taken in connection with the assompanying drawings in which:

Figure l is a schematic view of a type of cathode and anode structure for a gaseous electrical discharge device" illustrating a known arrangement for establishing a ring'count'er, but constructed to operatein one' direction onl V Figure 2 is a cross sectional view of-a gaseous electrical discharge tube embodying my invention and so constructed as to have therein two anodes arid a" plurality of cathodes so arranged that the tube is capable or being employed as an elementary digital computer compoliient' capable of adding and subtractingcounts' represented by input impulses;

Figure the alternate hookup arrangement: ot the cathodes is a top view ofthe anodes and cathodes Patented Apr. 23, 1957 2 Figure 4 is a perspective view of a cathode the two anodes showing details of construction and association, said cathode and anodes being shown as straight structures for simplicity, instead of curved, as when used in the tube;

Figure 5 is a sectional view through a' cathode and anode as viewed on the line 5--5 of Figure 3; V Figure 6 is a cross sectional view similar to Figure 2 but showing cathodes of a wire term and their "relation to the two anodes; 4 I Figure 7 is a top view of a portion of the anodes and cathodes; a Figure 8 is a radial or end view of a cathode employed in the gaseous electiic'al discharge tube of Figure f6;

Figures 9 and 10 are views of the cathode taken from other directions; and V Figure 11 is a diagrammatic view showing a computing system hookup employing a gaseous electric discharge tube as an elementary computer component thereoh In gaseous electricalfdischarge devices, particularly those in which there is a low pressure gas, the discharge between an anode and acathode tends to concentrate in any cavities of a cathode. Thus, if a cathode is given some special shape, the discharge can be forced to take place in a particular spot. For example, in the plurality of cathodes shown in Figure l" and numbered 10 to 15, these cathodes are provided with cup portions 16 and associated With the cathodes is a single anode 17 extending above the cup portion. When a discharge takes place between the anode and a cathode, it will occur at the cup portion, due to its special construction. By utilizing this construction for concentration of the dis charge in a cathode, it has been possible to produce a; gas discharge ring counter tube for counting input pulses, an example of such being shown in Figure l. In such a counter the anode 17 will be a so-called master anode and have voltage applied thereto through a resistor 18. Certain alternate cathodes, that is, those numbered 10, 12 and 14, are connected together in one circuit for receiving input impulses, whereas the other alternate cathodes, that is, those numbered 11, 13 and 15, are connected together in another circuit for receiving input impulses. These circuits are referred to as a and fb. If we now assume that impulses are being received in'the iz' circuit and a discharge is taking place between the anode and cathode 10, for example, it is known that by raising the potential on the fa cathodes and lowering the potential on the b cathodes, the discharge can be transferred from the No. It! cathode to the next adjacent cathode No. 11 because of the proximity of this latter cathode to the ionization caused by the discharge of the No. 10- cathode. The'same result can be accomplished also by lowering the potential on the cathodes of the bf circuit until there is a discharge between the anode and the No. Iicathode. Now the No. 11 cathode will draw more current, with consequential dropping of the potential of .the anode and extinguishing the discharge at the No. 19 cathode. In such an arrangement it is desirable to hold the potential on the No, 10 cathode normally constant and this can be done ,by a small condenser. Thus, it is possible to count in ut pulses at" the transfer of discharge takes place from one cathode to the-next cathode. Ina ring: manta from the arrange. merit shown in Figure 1', the cathodes wouldbe fastened into a circle, as well as the master anode; so that-the end cathode, such as 15,- will fire the first cathode, such as 10, if only six cathodes are employed.- Such agaseous electricaldischarge tube constructed in a manner as dis closed in Figure l and'particularl'y designed for a ring counter has a: disadvantage in. that itcan operate in one 3- direction only and therefore the counting accomplished can only be a'naddition or subtraction, but not both. With this knowledge of known gaseous electric discharge devices, and particularly one constructed to 'be employed as a ring counter, understanding of my invention will be simplified.

Referring now to Figures 2 to 5, a gaseous electric discharge tube embodying my invention will be described by way of example, this example being one particularly designed for use as digital computer component. One manner of this tubes use in a suitable counter will be iater described in connection with Figure 11. As shown in Figure 2, the gaseous discharge device comprises a conventional type of glass tube envelope 19 which has its interior 20 evacuated, degassed and then filled with a suitable discharge gas under a low pressure. Within this tube are'positioned ten cathode structures in a ring or circular arrangement, these being numbered 21 to 30, inclusive. In the particular tube shown, no special mounting for the cathodes is disclosed as any suitable mounting structure can be employed. Each cathode structure will have a conductor from the tube, these conductors being numbered 31 to 40, all indicated in Figure 3 and partially shown in the cross sectional view of Figure 2. Associated with all of these cathodes are two

master anodes

41 and 42, each being of circular form and connected to the exterior of the tube by

conductors

41 and 42.

The cathodes are of a special construction, as best shown in Figures 4 and 5. The cathode is formed from a single piece of material out to have a body 43 and two

extensions

44 and 45 projecting in opposite directions. The piece is then bent in a U-shaped form. The opposite walls of the body portion of the piece have struck out parts or flanges which are then bent to form

cups

46 and 47 adjacent the inner ends of the extensions. It is through these cup portions that the anodes extend, the inside anode 42 passing through the cups 46 and the outside anode 41 passing through the cups 47 of the cathodes. It will be seen that with these struck out portions forming the cups, there is a free path for the movement of ions from one anode to the other through the open slots formed when the

flanges forming cups

46 and 47 are struck out. With this free path it is possible for. the discharge to switch from one cup to the other.

By this ring construction of a plurality of my novel cathodes and two anodes, it will be possible to cause the discharge to advance around the ring from one cathode to another, or to transfer between one anode and the other without any advance from one cathode to another. The alternate numbered cathodes, that is, those numbered 21, 23, 25, etc, will be connected in one circuit indicated as X and the even numbered cathodes, that is, those numbered 22, 24, 26, etc., will be connected in another circuit indicated as Y. If a potential is now placed on anode 42 and the cathodes and there is, for example, a discharge taking place between cathode 21 of the X of discharge from one cathode to another cathode to take place around the ring in the opposite direction'to which it was taking place when there was a discharge between the cathode and anode 42, that is, in a counter-clockwise direction as viewed in Figure 4. This will be accomplished in the same manner as the transfer was accomplished when the discharge was taking place between the cathodes and the anode 42, that is, by incoming impulses causing the raising of the potential on the even numbered cathodes and lowering the potential on the odd numbered cathodes.

In the gaseous electrical discharge tube shown in Figures 6 to 10, the cathodes are made from wire instead of a piece of sheet metal. Half-0f the tube is shown in Figure 6 and from this figure it will be seen that there is provided the already described circular master anodes 4i. and 42 within the envelope 1, having the interior 20 thereof evacuated and filled with a suitable gas or gases at low pressure. The master anodes are positioned above the cathodes, whichare alsoarranged in the form of a ring. The six cathodes shown in Figure 6 {there being 10 all told) are indicated by the

numerals

21, 22, 23, 24', 25 and 26' and these cathodes are connected. to the exterior or the tube by the

conductors

31, 32, 33, 34, 35 and 36 in a manner described in connection with the gaseous tube shown in Figures 2 and 3. The alternate cathodes will be connected into the X circuit and the even cathodes will be connected into the Y circuits. This i illustrated in Figure 7 wherein is disclosed a segmental top view of the gaseous tubes shown in Figure 6 with the cathodes 23 and 24' being the only cathodes shown.

Each wire form of cathode will be of like construction and such can be readily visualized from Figures 7 to 10. As shown, there will be a straight central body portion 43' from the ends-of which extend the

portions

44 and 45. Each end portion extends downwardly at approximatelya 30 degree angle with one end portion being directed in one direction and the other portion in the opposite direction. At the center of the body portion 43' of the cathode the conductor leading to the exterior ofthe tube will be connected. With this construction of the wire type of cathode, the cathode will be positioned beneath the two

master anodes

41 and 42 in a manner disclosed in Figure 7 with the end portion 45 being directly beneath the master anode 41 and'the other end portion 44 being directly beneath the master anode 42.

The functioning of this wire type of cathode when associated with the master anodes as shown and embodied in the gaseous electrical tube disclosed is believed to be obvious from thealready described gaseous tube having the cup-shaped sheet. metal cathode shown in Figures 2 to 5. With the wire cathodes positioned below the anodes there will be a free path for the movement of ions from one anode to the other so that the discharge can, switch between the anodes. If a potential is placed on anode 42 and the cathodes and there is, for example,

circuit and anode 42, it will be obvious that when an input pulse is received so as to raise the potential of the circuit of the even numbered cathodes, that is, the Y, circuit, the discharge will be caused to transfer from the 21 cathode to the 22 cathode. As impulses are continued to be received, there will continueto be a transfer of the discharge, that is, from cathode 22 to cathode 23 and so v from one cathode to the next cathode. After this and fer takes place, it know possibleto causethc transfer cathode 24.

a discharge takingplace between cathode 23' of the X circuit and. anode 42, it will be obvious that when an input pulse is received so as to raise the potential of the circuit of the even numbered cathodes, that is, the Y circuit, the discharge will be caused to transfer from the end portion 44 of the cathode 23' to the adjacent If impulses are continued to be received, there will be continued transfer of discharge from one cathode to the next and so on around the ring in a clockwise direction'as seen in Figure 7. If, at the time p a discharge is taking place between cathode 24', for example, andanode 42 and the potential of anode 41 should be raised or the potential of anode 42 dropped, asalready described in connection with the gaseous tubes shown in Figures 2 and 3, then the discharge at cathode 24' will be transferred directly across the free path from the anode 42 to the anode 41 without any transfer of dis charge from one cathode to the next cathode. After this transfer takes place from one anode to the other, it will then be possible to cause a transfer of discharge from one cathode to another to take place around the ring in a counter-clockwise direction, as viewed in Figure 7. This will be accomplished in the same manner as the transfer was accomplished when the discharge was taking place between the cathodes and the anode 42, that it, by incoming impulses causing the raising of the potential On the even number cathodes and lowering the potential on the odd numbered cathodes. With the wire cathodes, the discharge between an anode and the cathode will always take place directly between the anode and the central body portion 43. of the cathode, due to the fact that the construction of the end portions of the wire cathode. is such that the concentration of the discharge willhave to be at this body portion of the cathode.

An example of the manner in which my two novel gaseous discharge tubes disclosed in Figures 2 to 5 and Figures 6 to 9 can be employed as an elementary digital computor component is illustrated diagrammatically in Figure 11. If it is desired to produce a counter, for example, which has radix 10 and is capable of making a count to. 9999., four of the tubes will be employed, these tubes being indicated as T T T and T and each tube being able to count either by addition or substraction to the number 10. Associated with each tube will be a system for generating impulses as, for example, a circuit commonly known as a Flip Flop circuit, also known as an Eccles-Jordan circuit, after the inventors thereof. This flip flop circuit includes a tube having two points of stability and when an impulse signal is received, the flip flop circuit will produce a positive and negative pulse into my novel gaseous discharge tube to cause an advance of discharge from one cathode to another.

The flip flop circuit for the first tube T will be connected to the cathode ring of this tube and receive the pulse input as indicated. Between this tube T and the next tube T and its flip flop circuit will be a carry circuit. Other carry circuits and flip flop circuits will be between tubes '1" and T and tubes T and T The T tubewill count digits, the T tube will count tens, the T tube will count hundreds and the T tube will count thousands. In the carry circuits between the tubes will be switches Pand N. All the switches P will be controlled simultaneously, as will be switches N, and these switches will have suitable automatic actuation which can be carried out by any well known electric or electronic means, the particular automatic actuation having nothing to do with my invention. There is also provided an anode switch as indicated by the block. To make the system complate, a sign indicator will be provided to exhibit whether the total count is negative or positive and connected with the four inputs of the tubes will be a zero coincidence detector. This detector will, when the four counters reach zero, switch the tubes for operation in the positive di rection, if thezero positions were reached by subtraction counts. At the time the detector switches the tubes, it will also cause a sign indicator to operate to indicate a minus number.

Ifwe now assume thatthe P switches are closed and there-is a pulse input to the flip flop of the tube T it will operate and the indicator thereof will begin to count the impulses as the discharge advances around the ring of cathodes'from one to the next adjacent one. After the number of pulses received in tube T have reached 9, the next impulse so advances the discharge as to indicate 0 in the tube T and simultaneously it will trip the flip flop circuitfor the tube T and cause it to indicate 1. The indicators will now read 0010, showing that the total count is 10. As additionalpulses are received, the tube T counts these and when another 10 are received the tube T will move to indicate 2. After the tube T counts to 9, it will move to zero when the tube T counts to the 0, orthat is 10. When this happens, the tube T now have a reading of0099.

will indicate 0, with the result that theflip flop circuit of the tube T will be tripped and it will then indicated, the total indication then by the indicators will be 0100, that is, 100. Positive counting proceeds to 9999 by the four tubes and carry circuits.

When substraction of the impulses is to be produced, the anode switch will operate to switch the anodes of the tubes, that is, from anode 42 to anode 41. Also, to perform subtraction, the switch P will be opened and switch N closed. If the counter system, for example, should have an indication of 0101 at this time, the input pulse will then move the discharge on tube T from position 1 to position 0 and the counter system will nowindicate 0100. Upon receipt of the next impulse to tube T the counter will go to 9 and since switch N is closed it will so trip the flip flop circuit of tube T that this tube will shift its indication from 0 to 9 and this shift in turn will cause the flip flop of tube T to trip its indicator so as to move it to 0. The counter system will If subtraction continues,- the tube T will continue to transfer its discharge counter clockwise with the, result that as each pulse is received the indicator moves from 9 to 8 to 7, etc.

By controlling the switches in an automatiemanner, the

3 subtraction and addition on the counter system is obtained with equal facility and there will be a direct reading of the resultant count atalltimes. Whenever the count is positive, the sign indicator will so show it. If the count should go below zero, that is, where all the indicators show 0000, then the coincidence detector would cause a switching, of the tubes and then carry circuits for operation in a positive direction and coinciding therewith, the sign indicator would show minus. Now there will be a positive addition again, but it will be known to be negative, since the sign indicator shows negative. A reset button can be employed to set all the indicators to zeroat any time desired.

Although I have shown specific embodiments of my improved gaseous discharge tubes and illustrated, a use thereof, it. is to be understood that numerous modifications can be made without departing from the funda-- mental principles of my invention which includes primarily the novel cathode and double-anode arrangement. It is therefore to be understood that the scope of my invention is not to be limited in any manner, except in accordance with the terms of the appended claims.

What is claimed is:

l. A gaseous discharge device comprising a gas filled to have two spaced discharge recesses with one recessassociated with one anode and the other with the other anode and further provided with a free ion path between the recesses, said cathodes also being so con-- structed and associated with each other that when one anode is energized the discharge can be transferred froml one cathode to the next in one direction only and when the other anode is energized the discharge can be-transferred from one cathode to the next but only in the] opposite direction.

2. A gaseous discharge device comprising a gas filled envelope, a plurality of cathodes positioned in series.

arrangement therein and two master anodes associated with "the cathodes, said cathodes each being formed to provide two laterally spaced discharge recesses and said cathodes and anodes. being so arranged that the like recesses on one side of the cathodes will beassociated with one-anode and the like recesses on the other side will be associated with the other anode,means.pmviding each of said cathodes with a free ion'path between. its recesses, andmeans on each cathode for transferring discharge :from one cathoderecess to the next cathode; I

iecess on the same side and in one direction only when the anode associated with these recesses is energized and for transferring discharge from a cathode recess on the opposite side to the next cathode recess on the same side but in the opposite direction from the first mentioned transfer when the other anode is energized.

3. A gaseous discharge device comprising a gas filled envelope, a plurality of cathodes positioned in series arrangement therein and two master anodes associated with the cathodes, said cathodes each being formed to provide two laterally spaced discharge recesses and said cathodes and anodes being so arranged that the like recesses on one side of the cathodes will be associated with one anode and the like recesses on the other side will be associated with the other anode, means providing each of said cathodes with a free ion path between its recesses, and discharge transfer portions on each cathode, said transfer portions being such that when one anode is energized there can be transfer of discharge from one cathode to the next in one direction only and when the other anode is energized there can be transfer of discharge from one cathode to the next in the opposite direction only.

4. A gaseous discharge device comprising a gas filled envelope, a plurality of cathodes positioned in series arrangement therein and two master anodes associated with the cathodes, said cathodes each being formed to provide two laterally spaced discharge recesses and a transfer portion extending from each, said transfer portions extending in opposite directions so that the cathodes when positioned in the series arrangement will have the transfer-portions on one of their sides all extending in a like direction and each will have its end adjacent to the recess of the next cathode which is on the same side and the transfer portions on the other sides of the cathodes will all extend in the opposite direction and each have its end adjacent to the recess of the next cathode on the same side, one of said anodes being associated with the discharge recesses of the cathodes on like sides and the other anode being associated with the discharge recesses of the cathodes which are on the opposite sides, each cathode being constructed to provide a free ion path be tween its discharge recesses.

5. A gaseous discharge device comprising a gas filled envelope, a plurality of cathodes positioned in series arrangement therein and two master anodes associated with the cathodes, said cathodes each being formed of a body provided with two laterally spaced discharge recesses in Walls thereof and a transfer portion extending from each wall, said transfer portions extending in opposite directions so that when the cathodes are positioned in the series arrangement the transfer portions on like walls of the cathodes all extend in a like direction with each having its end adjacent to the recess on the same side of the next cathode and the transfer portions on the other sides of the cathodes will all extend in the opposite direction with each having its end adjacent to the recess on the same side of the next cathode, one of said anodes being associated with the discharge recesses of the cathodes on like sides and the other anode being associated with the discharge recesses on the cathodes which are on the opposite sides, said walls of the cathodes being constructed with openings to provide a free ion path between the discharge recesses.

6. A gaseous discharge device capable of acting as a ring counter to accomplish either addition or subtraction of input pulses, said device comprising a gas filled envelope, an even number ofcathodes mounted therein in a ring arrangement and two master anodes associated with the cathodes, each cathode having separated dischargerecesses with one associated with oneanode and the other with the other anode, means for connecting the even numbered cathodes in one circuit and odd numbered cathodes in another circuit to receive the input impulses,

each of said cathodes being constructed to provide a free ion path between the discharge recesses so that upon changing the energization of the anodes one to the other the discharge can remain on a cathode, said cathodes also being so constructed that a discharge canbe transferred from one cathode to the next cathode in one direction only around the ring arrangement when one anode is energized and from one cathode to the next cathode in the opposite direction around the ring arrangement when the other anode is energized.

7. A gaseous discharge device capable of acting as a ring counter to accomplish either addition or subtraction of input pulses, said device comprising a gas filled envelope, an even number of cathodes mounted therein in a ring arrangement and two master anodes associated with the cathodes, each cathode having separated discharge recesses with one associatedwith one anode and the other with the other anode, means for connecting the even numbered cathodes in'one, circuit and odd numbered cathodes in another circuit to receive the input impulses, each of said cathodes being constructed to provide a free ion path between the discharge recesses so that upon change in energization of the anodes the discharge can remain on a cathode, said cathodes also being so constructed that a discharge can be transferred from one cathode to the next cathode in one direction only around the ring arrangement when one anode is energized and from one cathode to the next cathode in the opposite direction around the ring arrangement when the other anode is energized, said last named cathode structure comprising a transfer portion extending in opposite directions from the portion containing the discharge recesses and so positioned that when the cathodes are in their ring arrangement each cathode will have a transfer portion overlapping a transfer portion on each adjacent cathode but laterally spaced therefrom.

8. A cathode structure for use in a gaseous discharge tube to permit discharge between the cathode and either of two laterally spaced anodes associated therewith and also the transfer to other cathodes on opposite sides thereof, said structure comprising a body portion and spaced apart end portions extending in opposite directions from the body portion, said body portion being arranged to extend in spaced relation between the anodes and the spaced apart oppositely extending end portions being arranged so that each will be coextensivewith an anode, said body and end portions being so constructed and arranged with respect to each other and the anodes that the concentration of discharge will occur between an anode and the body portion of the cathode and there will'be a free ion path between the anodes. p

9. A cathode structure for use in a gaseous discharge tube to permit discharge between the cathode and either of two laterally spaced anodes associated therewith and also the transfer to other cathodes on opposite sides thereof, said structure being made from wire and comprising a body portion and spaced apart end portions extending in opposite directions from the body portion, said body portion arranged to extend in spaced relation between the anodes and the spaced apart oppositely extending portion being arranged so that each will be coex-' tensive with an anode, but in diverging relation thereto.

10. A cathode structure for use in a gaseous discharge tube to permit discharge betweenthe cathode and either of two laterally spaced anodes associated therewith and, also the transfer to other cathodes on opposite sides. thereof, said structure comprising a body portion and spaced apart end portions extending in opposite directions from the body portion, said body portion being arranged to extend in spaced relation between theanodes and the spaced apart oppositely extending portion being arranged so that each will be coextensive with an anode, but in diverging relation thereto. a

11. A cathode structure for use in a gaseous discharge tube to permit discharge between either of two laterally spaced anodes or between cathode structures, said cathode structure comprising a wire structure having a straight body portion of a length approximately the distance between the anodes and two end portions extending from the ends of the body portion, said end portions extending at substantially right angles to the body portion, in opposite directions and having a diverging relationship.

12. A cathode for a gaseous discharge tube having two laterally spaced anodes, comprising a body having laterally spaced sides, a bottom connecting said sides and a flange extending laterally upwardly and outwardly from the lower portions of each side, said flanges being opposite each other and each flange providing a recess through which an anode may extend longitudinally; each side of said body having an opening opposite said flange adapted to provide a free ion path between said anodes; and each said side extending longitudinally beyond the other side, one side so extending in one direction and the other side in the opposite direction.

13. A cathode as defined in claim 12, wherein said flanges are integral with said body and said openings have a size corresponding to that produced when each flange is struck out from the corresponding side.

14. In a gaseous discharge tube, the combination of two laterally spaced anodes and a plurality of cathodes disposed in series and longitudinally along said anodes, each cathode having a body portion extending laterally in spaced relation to a direct line between said anodes, and

projections extending longitudinally from said body in spaced relation to each said anode with the projections of all said cathodes associated with one said anode extending in one longitudinal direction and the projections of all said cathodes associated with the other anode extending longitudinally in the opposite direction.

15. In a gaseous discharge, tube, as defined in claim 14, wherein said anodes are rings and said cathodes are disposed in series around said ring.

Hough May 2, 1951 Townsend Nov. 20, 1951