US2704336A - Pulse counting tube - Google Patents

Description

March 15, 1955 KAZAN 2,704,336

PULSE COUNTING TUBE Filed Jan. 3, 1951 2 Sheets-Sheet l mauuns 300w INVENTOR.

BENJAMIN KAZAN BY W Mn i J 3- N a 26x6 20555 i March 15, 1955 B. KAZAN PULSE COUNTING TUBE 2 Sheets-Sheet 2 Filed Jan. 3, 1951 QUE LNHHHHO EICIONV INVENTOR.

BENJAMIN KAZAN BY gn M vdE United States Patent PULSE COUNTING TUBE Benjamin Kazan, Long Branch, N. 1., assignor to the United States of America as represented by the Secretary of the Army Application January 3, 1951, Serial No. 204,257 14 Claims. (Cl. 31518) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to electron discharge apparatus and more particularly to electronic counters.

In the art of electronic counting, it is usually necessary to employ a series of cascaded tubes together with appreciable associated circuitry. Such devices are of relatively large size and complex construction. Moreover, in view of the complex circuitry involved, such as electronic counter may be relatively expensive to construct and difficult to maintain in proper operating condition.

It is therefore an object of this invention to provide a simple and compact means for registering the count of rapid impulses in a binary or higher number system.

Another object is to make possible a self-resetting counter of compact and economical construction.

Still another object is to provide a simple and compact electronic device capable of yielding one output pulse in response to the accumulation of a prescribed number of applied input pulses.

It is yet another object of my invention to enable selective deflection of an electron beam in an electron discharge device in accordance with incoming signal pulses such that the beam will be held focused-upon a discrete portion of the anode after cessation of each signal ulse. p In accordance with this invention, electron discharge apparatus especially suitable for counting comprises a strip cathode, an anode angularly disposed with respect to the emitting surface of the cathode, means for producing a constant magnetic field in the anode-cathode. region for directing the electron beam in a prescribed direction and deflecting the beam in accordance with the polarity of the incoming pulse so. that it nnpmges upon successive portions of the anode.

In accordance with one illustrative embodiment of this I? invention, the electronic counter comprises a strip cathode and an undulated arcuate anode mounted opposite said cathode, means for deflecting the electron beam to successive positions on the anode in accordance with incoming signal pulses, means for stabilizing the electron beam on a preselected portion of the arcuate anode after each incoming pulse, and means for returning the electron beam to its initial starting position after a prescribed number of successive lIlCOITllHg pulses.

. For a better understanding of the present invention to- H a gether with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a perspective view of an electron discharge device illustrative of one embodiment of my invention;

Fig. 2 is a view in section along plane 2-2 of Fig. 1

and includes the electrical connections of electrodes shown in Fig. 1'

Fig. 3 is an explanatory diagrammatic curve;

Fig. 4 is a perspective view of an electrode assembly Like reference numerals indicate similar parts through-" out the several views.

Referring now to Figs. 1-3, there is shown an electron discharge device comprising an evacuated envelope 2 hav- "ice ing mounted therein an electrode assembly, which may be referred to generally by the reference character 4.

The electrode elements are supported betwen a pair of spaced parallel insulating members such as mica discs 6 and 8 and comprise respectively cathode 10, anodes 12a to 12e angularly displaced with respect to cathode 10 and a collector anode 14. Encompassing the electrode element is a cylindrical metal shield 16. The electrode assembly 4 may be conventionally supported from a stem 18 terminating in a press 20. Extending through the press 20 are conductors 22 for electrically connecting the electrode assembly 4 to the operating circuits.

Extending between the discs 6 and 8, and fitted in apertures therein, is linear cathode 10, which may be of the indirectly heated type, comprising a rectangular shaped sleeve 24 longitudinally positioned in approximately a radial plane within envelope 2. A restricted portion of one of the outer fiat surfaces of sleeve 24 is coated with a thin longitudinal strip of thermionic material 26, such as barium or strontium oxide. Heating current for the cathode is provided in accordance with known practice. Surrounding cathode 10 is an accelerating grid 28 which is maintained positive with respect to said cathode by approximately 50 volts. By this arrangement, a ribbon shaped electron beam of rectangular cross section is produced when the electrodes are energized as hereinafter described.

A plurality of linearly aligned metal anodes 12a to 12e are angularly disposed with respect to cathode strip 26. Considering the position of cathode strip 26 on a reference longitudinal plane of zero degrees, then each of the anodes 12 may be assumed to be in a longitudinal plane approximately 230 clockwise from said reference plane. It will be understood, of course, that 230 is merely illustrative and that the anodes 12 may be longitudinally positioned at some other convenient angle with respect to cathode strip 26. The anodes may be equally spaced from one another by a distance approximately equal to their width, and are supported in position by means of apertures in the insulating members 6 and 8. As shown, the anodes are connected together in a group by a tie-wire 30, one end of which is connected to leadin conductor 32 sealed in the press 20. Although five spaced anodes are shown in the specific embodiment illustrated, a greater or lesser number of anodes may be employed. The number of anodes used determines the number of pulses the device may count. Thus, if five pulses are to be counted, five anodes are employed. If ten pulses are to be counted, then ten anodes are utilized. To collect the electrons which pass between the anodes 12, rectangular collector anode 14 is mounted in a lonfgitudinal plane behind anodes 12 and is spaced thererom.

As shown in Fig. 2, a load resistor 34 is connected between the anodes 12 and collector anode 14 which is placed at a positive potential with respect to the potential of cathode 10 by means of battery 36 or any other suitable potential source. The incoming pulses are applied between terminals 38 and 40 and are coupled to the anodes 12 by capacitor 42. Also coupled to anode 12 is a utilization circuit 44 which may be of any one of the conventional circuits well known in the art for discharging the anodes 12 when a predetermined potential is reached by said anodes.

A uniform axial magnetic field of prescribed intensity may be supplied in any desired manner as by a coil 46 carrying a steady current in accordance with known practice. As a result, the electron trajectory is curved as shown in Fig. 2. The strength of the magnetic field and its direction are made such that, in the absence of incoming pulses, the electrons emanating from the cathode 10 are concentrated into a substantially curved rectangular beam 48 focused upon the anode 12a. As is well known in the art, any change in potential applied to anode 12 will interact with the prescribed axial magnetic field to change the curvature of beam 48 and thus effectively shift the terminus of the beam.

In operation, the anodes 12 are maintained at a moderately high positive potential with respect to cathode 10, for example, several hundred volts. As shown, this positive potential is applied to the anodes 12 through load 'voltage. 'tially impinging upon any of the anodes 12, it is. autoresistor 34. If the positive pulses applied to the anodes 1 2 through capacitor 42 are of 'sufiicient amplitude, then, as each of the anode voltage pulses are applied, interaction of the axialmagnetic field and the applied pulses :will cause curvature of beam 48 to change, and, consequently the terminus of the beam will be shifted from one anode to the next adjacent anode. Thus if successive positive pulses of short duration and suificient amplitude are coupled to the anodes 12 throughcapacitor 42, the.b'eam terminus will be successively shifted'from the anode 12a to the anode 12e. To better explain the operation, reference is made to the static characteristic curve shown .in

Fig. '3, illustrating the variation of anode currentwith respect to applied anode voltage. The amount of current drawn by each of the anodes will, of course, be dependent on the relative portion of beam 48 which 'isintercepted by each anode as the beam is successively deflected from anode 12a to 12e.- If, for example, beam 48 intercepts I a small portion of the surface of anode 12a, then little anode current will be drawn. However, if beam 48 covers all of anode 12a, then maximum anode currentwill be drawn. Thus, as the anode voltage is-increased, the current at each of the anodes 12 will rise from zero'to a I 1:

anode circuit, a load line may be conventionally drawn in Fig. 3 as shown to determine the point-of operation, or

stability, for each successive anode. As is well .known in the art, only the points of intersection of theload line with the positive sloped portions of the undulated curve as indicated at U, V, W, X an Y will be stable, and are known as points of equilibrium. For example-if, for any reason, beam-48 should be shifted by an increase in-anode voltage so that more of the beam impinges on 12a-than that which corresponds to the voltage U, then the current drawn through load resistor 34 will increase, thereby causing a corresponding voltage drop acrossthe load so that the anode voltage Will automatically be decreased and return towardsthe voltage designatedat U: -'If, on

the other hand, beam 48 is shifted by a decrease in :anode voltage, the anode current drawn will correspondingly be decreased thereby causing the anode voltage at 1211 to increase, thus tending to shift the beam backagain to the stabilized voltage point U. Thus if the beam position is shifted by a change in the anode voltage, the

: change in intercepted beam current atthe anode will cause an opposite voltage'chan'ge across'load resistor 34 which 'will tend to maintain the beam in the equilibrium position. After a pulse is applied to the input circuit, beam 48 will be deflected from 12a to 12b, and only that portion of thebeam will impinge on 12b so that the anode current drawn will cause the anode potential to be -stabilized at a potential represented by V'of Fig.3. This anode voltage, of course, is necessarily higher than. the plate voltage represented by U. That portion of beam 48 not impinging on anodes 12- does not afiect the volt- 'agedrop across resistor 34 and-is intercepted-by collector anode 14. It can readily be seen therefore, that by impressing a succession-of voltage pulses on the anodes 12, the beam terminus may be successivelyshifted from oneequilibrium, or stable, position to thenext. Thus, as

each successive pulse is applied to the anodes 12, the beam is shifted or deflected to the next successive anode.

It will'be appreciated therefore that the beam may shift successively from one anode to the next by positive pulses supplied through capacitor 42 and held upon any of the anodes 12 against which it is deflected by virtue of the equlhbrium voltage points, each of which corresponds represented by the undulated curve illustrated in Fig. 3. 'With a predetermined load resistor such as 34 in the 4. -to anode 12a. of course, if the polarity of the income ing pulse is reversed, the beam position may be deflected in the opposite direction from anode 12s to 12a, assuming the beam is positioned initially on anode 12e.

Fig. 4 illustrates anothervembodiment of an electrode assembly which may bemounted in evacuated tube 2 between spaced parallel insulating discs 6 and 8.

Extending between discs 6 and 8 and centrally positioned within evacuated tube 2 is a trough shaped cathode 50. To provide a rectangular shapedelectron beam, the outer surface of trough base 52 of "the cathode is coated with a thin longitudinal stripv ofthermionic emitting material 54,'such as barium or strontium oxide. Spaced from trough base 52 and parallel thereto, is an accelerating grid 56 which is provided with a longitudinal slot 58 disposed-opposite thermionic strip 54.

Encompassing cathode 50 and accelerating grid 56 is a coaxial cylindrical anode 60, which in turn' is surrounded by collectoranode 62 radially spaced from anode 60. An integral portion of the cylindrical surface of anode 60, for example, approximately 120, is provided with an undulated structure 64 which comprises a series of triangular shaped teeth 66a to 66k, hereinafter re+ ferred to as counting anodes, having successively increas ing peaks. As shown, the counting anodes 66 are arcu? ately disposed between exposed edges 68 and 70 of cylindrical anode 60. In the specific embodiment illustrated, thermionic strip 54 is aligned with :edge Y70 and, as hereinafter explained, the electron beam will be deflected in a clockwise direction.

A load resistor 34 is connected between collector anode 62 and the counting anodes 66. A suitable. sourceof 1 positive potential may be applied to collector anode 62 by means of battery 36 or any other suitable potential source. This positive potential is also applied to the counting anodes 66 through load-resistor 34. A uniform axial magnetic field of prescribed intensity may be supplied in any desired manner as by coil 46 carrying a steady current in accordance with known practice.- The constant magnetic field is made such that, in the absence of incoming pulses, the electrons emanating from thermionic strip 54 and accelerated by grid 56 are con: centrated .into asubstantially curved rectangular beam thus impinging on anode 66a. The incoming pulses may be coupled to said countinganodes by means of capacitor 42 or by any other means well known in the art. Although in the specific embodiment illustrated, ten

counting anodes are shown, it is to be understood that 0 ':a lesseror greater number of counting anodes may be employed, depending on the number of pulses: the de- 'vice may be required to count. Thus, inthc specificillustration, ten pulses are to be counted. If five pulsesare to be counted, then only five counting anodes are'utilized.

Spaced from counting anode 66k and parallel thereto, is a flyback control plate 72. 'It is tobe assumed that the surface of the flyback plate is such that its secondary emission ratio is less than one when bombardedas here- I inafter described. As shown in Fig. 5, flyback plate 72 f and grid 56 are connected to common grid-leaklresistor to a successively higher value of D. C. equilibriumw',

Stated in another way, when the beam is .par-

matically held upon that anode until the next pulse is applied.

In the illustrative case shown in Fig. 1, it hasbeen assumed that, after five pulses, the anode-voltage corresponding to point Y of Fig. 3 is sufiiciently high to trigger external utilization circuit 44. Thus, after :the fifth pulse, the counting sequence may be repeated. f

In the specific embodiment of the invention illustrated and 'above described, positive pulses have been applied to successlvely shift the beam position from anode 12a 74, which in turn is connected to the positive terminal of battery, 76 or other suitable source. Grid-leak capacitor 78 is connected across resistor 74. This arrangement permits the counting tube to reset itself automatically after'th'e required number of pulses have been applied tothe counting anodes 66 through capacitor 42.

7 During operation, thecounting anodesl66 are maintained at moderately high positive potential with respect tocathode 50. As successivenegative pulses of short duration are coupled to said counting'anodesthrough capacitor 42, the electron beamwwillcbe shifted successively in a clockwise direction from counting anode 66a to counting anode 66k. As a function of the anode voltage, the plate current may be represented by the 'undulated curve shown in Fig. 6, the load line corresponding to resistor 34 beingindicated in the convntionaLmanner. As previously explained, each incoming pulse shifts the beam to the.successive counting anode where it automatically assumes .a state of stable voltage equilibrium indicated by points A to K in Fig.6. Consequently, when the electron .beam is impinging upon a, particular anode, it is automatically heldf upon that anode until the "next'pulse' 'is applied atwhich time the beam is shifted to the adjacent anode. Thus, it will be appreciated that the beam is successively shifted clockwisealong the counting anodes 66.

Upon application of the tenth input pulse, the electron beam impinges on flyback plate 72. As a result, control grid 56 is driven negative, thus cutting off the beam. When the negative charge has sufliciently leaked ofi through grid leak resistor 74, the beam will return to anode 66a at a stable equilibrium voltage point. Thus after dthe tenth pulse the counting sequence may be repeate It is to be understood, of course, that, if desired, the external utilization circuit described in connection with Fig. 1 may also be used with the device shown in Fig. 4. By using this arrangement, flyback plate 72 may be eliminated.

While there has been described what is at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. Electronic discharge apparatus comprising means for producing a ribbon-shaped electron beam of substantially rectangular cross section, a target electrode intercepting the terminus of said beam, means for establishing a constant magnetic field to deflect said ribbon-shaped beam, said field being of such intensity as to focus the terminus of said beam upon one end of said target electrode, means for successively shifting said beam to discrete portions of said anode for producing an undulated target electrode current with respect to electrode target voltage, and means for holding said beam on the discrete portions of said anode against which it is directed.

2. Electron discharge apparatus comprising means for producing a ribbon-shaped beam of substantially rectangular cross section, an anode intercepting the terminus of said beam, means for establishing a magnetic field to concentrate said ribbon-shaped beam in a curved path, said field being of such intensity as to focus the terminus of said beam upon one end of said anode, a source of input pulses, means for applying said input pulses to said anode whereby said beam is successively shifted to impinge on discrete portions of said anode to produce an undulated anode current with respect to anode voltage, and means for holding said beam on the discrete portions of said anode against which it is directed.

3. Electron discharge apparatus comprising means for producing a ribbon-shaped electron beam, a plurality of interconnected spaced target electrodes to intercept the terminus of said beam, means for producing a constant magnetic field to concentrate said beam in a curved path, said field being of such intensity as to focus the terminus of said beam upon one of said target electrodes, means for shifting said beam successively from one target electrode to the next adjacent target electrode whereby an undulated electrode current is produced, and means for holding said beam upon the electrode against which it is directed.

4. The electron discharge apparatus in accordance with claim 3 wherein said target electrodes are linearly aligned.

5. A pulse counting circuit comprising an electron tube, means positioned longitudinally within said tube to produce a ribbon-shaped beam of substantially rectangular cross section, a plurality of spaced target anodes to intercept the terminus of said beam, said anodes being linearly aligned co-planar with said beam producing means and angularly disposed therewith, means for producing a constant magnetic field to concentrate said beam into a curved path and of such intensity as to focus the terminus of said beam upon an end anode, means for shifting the terminus of said beam to successive anodes to produce an anode current having an undulated characteristic with respect to anode voltage, and means for holding said beam upon a portion of the anode against which it is directed, said holding means comprising a load impedance having one end connected to said target anodes to provide a plurality of stable anode voltage points.

6. A pulse counting circuit comprising an electron tube, a cathode mounted longitudinally in a radial plane within said tube to produce a ribbon-shaped electron beam, an accelerating grid encompassing said cathode for the entire length thereof, a plurality of spaced target anodes to intercept the terminus of said beam, said anodes being linearly aligned in a longitudinal plane angularly disposed with respect to said radial plane, means for establishing a uniform axial magnetic field to concentrate said beam in a curved path, said field being of such intensity as to focus the terminus of said beam upon an end anode, means for shifting the terminus of said beam to successive anodes to produce an anode current having an undulated characteristic with respect to anode voltage, and means for holding said beam upon a portion of the anode against which it is directed, said holding means comprising a load resistor having one end connected to said target anodes to provide successive stable anode voltage points.

7. A pulse counter in accordance with claim 6 wherein said target anodes are angularly displaced approximately 230 with respect to said radial plane.

8. A pulse counting circuit comprising an electron tube, means longitudinally positioned in a radial plane within said tube for producing an electron beam of substantially rectangular cross section, a plurality of spaced and linearly aligned target anodes to intercept the terminus of said beam, said anodes being positioned in a longitudinal plane angularly displaced with respect to said radial plane, means for establishing a longitudinal magnetic field between said beam producing means and said anodes for deflecting said beam, said field being of such intensity as to focus the terminus of said electron beam upon an end anode, means for applying input pulses to said anodes whereby said beam is shifted to impinge on successive anodes to produce successive discrete anode voltages, and means for holding said beam upon the anode against which is it directed, said holding means comprising a load impedance connected to said target anodes to provide a plurality of stable anode voltage points.

9. A pulse counter in accordance with claim 8 wherein said anodes are spaced from each other a distance approximately equal to the width of said anodes.

10. An electron discharge apparatus comprising means for producing a ribbon-shaped electron beam of substantially rectangular cross section, an anode encompassing said electron producing means to intercept the terminus of said beam, an integral portion of said anode having an undulated surface opposite said cathode, means for establishing a constant magnetic field to concentrate said electron beam in a curved path, said field being of such intensity as to focus the terminus of said curved beam upon one end of said undulated surface, means for successively shifting said electron beam to discrete portions of said undulated anode surface, and means for holding said beam in the discrete portion of said undulated anode against which it is directed.

11. An electron discharge apparatus in accordance with claim 10 wherein said undulated surface comprises a plurality of triangular shaped teeth.

12. An electron discharge apparatus in accordance with claim 10 wherein said holding means comprises a load impedance connected to said anode.

13. A pulse counting circuit comprising an electron tube, means axially positioned within said tube for producing a ribbon-shaped electron beam, an anode encompassing said electron source to intercept the terminus of said beam, an integral portion of said anode having an undulated surface, said undulated portion comprising a plurality of triangular shaped target anodes having successively increasing peaks, the first of said target anodes being substantially aligned with said beam producing means, means for establishing an axial magnetic field to concentrate said electron beam in a curved path, said field being of such intensity as to direct the terminus of said curved beam upon a portion of said first target anode, means for applying input pulses to shift the terminus of said beam to successive target anodes, means for successively holding said beam on a portion of the anode target against which it is directed, said holding means comprising a load impedance having one end connected to said anode, and means for deflecting said beam to again impinge the terminus of said beam on said first anode target after the application of a predetermined number of said input pulses.

14. The pulse counting circuit in accordance with claim 13 wherein said last mentioned means comprises a 2,027,017 Brett Jan. 7, 1936 -2,07 5478 Linder Mar. 23, 1937 "2,224,677 Hanscom Dec. 10, 1940 Fleming-Willi 1y 10,-1945 Skelle'tt Feb 19,1946 Montani Mar} 8, 1 49 Clark June 28, 1949 Skellett July 5, 1-949 Alfven at al June 27; 1950 Clark =Ot. 9, 1951

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