US2597360A - Electron ratchet tube - Google Patents

Description

May 20, 1952 k. J. MOON 2,597,360

. ELECTRON 'RATCHET TUBE Filed Nov. 17, 1944 3 Sheets-Sheet 1 Possxer 1/. Moo/v Arroeuzs/ y 1952 R. J. MOON ELECTRON RATCHET TUBE 3 Sheets-Sheet 3 Filed NOV. 17, 1944 x his X mw wh sk b I D D h h b M w E Mqsm V QHESQQ m ROBERT J. MOON Patented May 20, 1952 ELECTRON RATCHET TUBE Robert J. Moon, Chicago, Ill., assignor to the United States of America as represented by the Secretary of War Application November 17, 1944, Serial No. 563,935

12 Claims.

1 The invention described herein may be manufactured and. used by or for the Government for governmental purposes, without the payment of any royalty thereon. I

This invention relates to measuring devices and more particularly to means for counting pulses. The objects include the provision of means for counting pulses. Other objects will appear as this description proceeds.

The invention consists in providing means for deflecting an electron beam angularly a given amount, for example, thirty-six degrees, each time a pulseto be counted is received. A grid may be positioned at any suitable point and will pick up one impulse for a large predetermined number, for example, ten, applied since the beam will rotate past said grid only once per revolution. The output of the said grid may feed another similar tube which will (assuming thirty-six de gree rotation per pulse) have one revolution for every one-hundred pulses applied to the first tube. If the output of a grid of the second tube feeds a third, and the output of the third a fourth, etc. it is possible to countn pulses where n is the number of pulses required for a complete revolution in each tube and m is the number of tubes. Such counters can count pulses of frequencies as high as ten megacycles.

In the drawings:

Figure 1 is a diagrammatic view of a simplified form of the invention.

. Figure 2 shows the hookup of certain deflecting plates'of the apparatus.

Figure 3 illustrates the grids of the tube of Figure 1.

Figure 4 illustrates the hookup of a number of the tubes of Figure 1 as arranged for counting purposes.

Figure 5 is a diagrammatic view of another form of tube incorporating novel features.

Figure 6 is still another diagrammatic view incorporating the invention.

Figure (illustrates another arrangement of grids. Figure 8 is a front view of the scale of the C-l and C-6. The top of thebulb is suitabl treated to form a fluorescent screen ll.

As shown in Figure 2 there are ten deflecting plates disposed 36 angular degrees apart and designated B-l, B2, B-3, B-4, B-5, B-6, B4, 1343, B-9, and B-0. Each of these plates is located directly under complementary grids 0-4, C-2, C3

C-4, (3-5, 0-6, 0-1, C-8, C-9; and C0. Let us assume that the electrons from gun E are emitted and that for starting purposes there is a charge on plate B-l. This charge may be one tem- .porarily placed on plate'B-l for starting purposes. The electrons are then directed toward grid 0-! Th connections and arrangements are such that the charge on plate 13-! will be maintained as long as there is no pulse fed at A. This will be explained later." Preferably although not necessarily, the several plates B-l to 3-0 are interconnected by high resistances such as R5. The electrons will remain passing plate B-I and striking C-l until a pulse is fed at A. A positive pulse will tend to deflect the electron beam radially toward D, hence since grid C-Z' overlaps C-l the electron beam will be intercepted'by C-2 instead of C-I (however if a pulse of opposite polarity is fed in at A the beam will be shifted so it is intercepted by 0-0 instead of C-l When the electron beam is intercepted by 0-2 the plate 34 now becomes the most positive (for reasons to be described) and concentrates the beam on rid C-Z where it is held or locked after the cessation of the pulse by electrical circuit reactions analogous to a mechanical rachet. When another pulse enters lead-in wire A the beam is again shifted radially to grid C 3. Hence for every positive pulse received at A the beam is rotated angularly thirty-six degrees in one direction and for every negative pulse received at A the beam is rotated angularly in the other direction.

It is worthy of note that in Figure 3 the grids overlap such, that if clockwise directions are assumed, the leading edge of grid 0-4 is almost on a radial line with the trailing edge of 0-3. The arrangement is such that radial deflection of a beam concentrated on 0-2 will cause shifting to either 0-! or C3. Figure 7 shows still further overlapping in this respect.

In each tube there is a transfer grid G which is confined to a thin wire extending in the tube along a single radius. vThis wire G may feed another similar tube. If only one tube is used the wire may be omitted. However, if as in Figure 4 several tubes are used, the transfer grid G of tube T-I feeds lead-in A of tube T-Z and trans- 3 fer grid G of tube T-2 feeds lead-in A of tube T-3, and grid G of tube T-3 feeds lead-in A of tube T-4 and so on. The last tube of the series does not require a transfer grid G or its equivalent.

As shown in Figure 8 each fluorescent screen I i has graduations from zero to nine. Let us assume that in a given known time interval there were 8753 pulses entering wire A of Figure 4., said pulses being the ones desired to be counted. The beam of tube T-I would rotate 875.3 times stopping on 3. The beam of tube T-2 would rotate 87.5 times stopping near 5. The beam of tube T-3 would rotate 8.7 times stopping at 7. The beam of tube T-4 would make eighttenths revolution stopping on 8. When the pulses stopped being fed at A the several beams would stop at the positions indicated and would strike the fluorescent screens l I thus making the desired spots at the proper places. One reading the positions of these spots would read 8753 which is the exact number of pulses fed in at A.

The grid sectors C shown in Figs. 1, 3, 5 and 6 may be made of sheet metal perforated with numerous small holes or of fine mesh wire screen to permit some of the electrons from the electron gun E to 'pass through to the fluorescent screen H where the position of the luminous spot may be read against the scale shown in Fig. 8.

Referring now to Figure 5 the electron gun E, the plates 13-! and B-6, the conical member D, grids C-l and 0-6, fluorescent screen I l, and certain additional features will now be described. A vacuum tube has its grid 23' connected to 0-1 and its plate 22 connected to B-l. The plate 22 and cathode lead 2| are shunted across a high voltage battery 24 in the usual manner, except through a high resistance 25. This arrangement enables the beam to be concentrated on grid C-l once it strikes grid C-l in the following manner. When the beam strikes C-l the grid 23 immediately becomes negative and stops current flow in tube 20, hence there is no drop in resistor 25 and the voltage on deflecting plate 3-! rises thus attracting the electrons from the gun and concentrating them on C-I. There is a similar tube 20, similarly-connected to each of the ten grids (7-! through C 0 and respectively to each of the deflecting plates B-l through B-ll. It is to be noted that the grids of all ten tubes 20 are normally left floating where they naturally adjust themselves slightly positive relative to their respective cathodes. All ten control tubes are therefore normally conducting and owing to high resistors 25 all plate potentials together with defleeting platesB-l to 13-9 are normally low. It is now evident that if resistor 25 co'rresponding to 13-4 is momentarily shorted, the electron beam will be deflected to grid sector 0-! wher it is locked by the blocking of tube number one of tubes 20. It is further evident that a positive pulse applied to anode D will deflect the electron beam from C-l radially inward to the overlapping tip of grid sector C-.2, which as in the previous case blocks tube number two thereby allowing deflecting plate B-2 to rise to full plate potential. The electron spot therefore moves radially outward on sector C-2 where it remains in equilibrium as it previously did on sector C-l. The negative charge accumulated on 0-1 leaks off through the grid of tube number one. Th otential of 3-4 then falls to normal equilibrium with all the other deflecting plates, leaving B-2 only at full plate potential. Thus the positive pulse applied to D has shifted the electron beam from equilibrium on 0-! to equilibrium on 0-2. A second pulse on D will shift the electron beam from 0-2 to C-3 and so on, the beam shifting one step for each pulse. Similar tube arrangements are employed with each of the tubes T-2, T-3 and T-l. There are other and simpler arrangements for making the beam concentrate on the grids but inv accordance with the law I have described the one which I believe to be the best.

Referring now to Figure 9 which .is a more detailed diagram of the structure shown in Fig. 5. The electron gun and its associated components are shown at E in the conventional manner. The deflecting plates are shown in schematic section at B-l and B-B, the conical pulse electrode being indicated at D-l. The circular diagram immediately to the right of the electron gun represents the ten deflecting plates 13-! throughB-D assembled symmetrically about the axis of the tube looking toward the electron gun. the pulse electrode D-I being shown at the center. The adial resistors R-4 connect the individual deflecting plates 13-! through B-O to the source of positive potential at a of the power supply and corresponds to resistor 25 and battery 2'4 of Fig. 5 respectively. The resistors R-5 correspond to resistors R-5 of Fig. 2. Electrode F of Fig. 5 is represented by the circle F at the center of the diagram. The assembly of ten spiral grid sectors C-l through C-D, corresponding respectively to the deflecting plates B-l through B-U is shown diagrammatically to the right of electrode F, the order of the sequence being that seen looking along the axis toward the electron gun. The control tubes 20 of Fig. 5 are shown in detail as the ten tubes V-l through V-fl whose anodes 22*are connected to their respective deflecting plates 3-! through B-O. The pulses to be counted are applied to the input terminals X--Y through condenser 30. A positive pulse, shown diagrammatically at 48, is applied to lead-in wire A, connected to pulse electrode D-l. If the electron beam'is normally at rest, for example, on grid sector G4 at the spot 46, the efie'ct of the positive pulse on electrode D-l is to pull the beam radially downward to position 52 on sector 0-2. As previously explained, the negative charge on sector C4 and grid 23 leaks off through'th'e tube, or through a suitable grid leak resistor (if necessary) while the negative charge on grid sector C-.2 isxin the process of building up. Thus the potential of defleeting plate B-l falls while that bf'B-Z rises. during which process the electron beam is'shifired from spot 52 to 54 on sector C-2'where it remains fixed. A second positive pulse on D-I will shift the electron beam to grid sector 0 3, each subsequent pulse advancing the electron beam one grid sector. The initial position of the electron beam is on sector C-U so that at the tenth pulse the beam has progre'ssedten steps to sector 'C'-'0 again. In its passage to final equilibrium posi tion on 0-0, the electron beam sweeps across transfer electrode G momentarily reducing its potential. Electrode G is preferably connected to pulse'electrode D-2 of the second counter tube T-2 through an intermediary tube U 2 which is biased to be normally conducting by grid resistor R-9. The negative pulse on transfer electrode "G connected to pulse output terminal G1 drives the control grid negative beyond cut- 01T as indicated schematically at'56. The interruptionof plate current through resistor R- B causes fullplate potential to be applied to lead-in terminal- A" and pulse electrode D-Z as shown diagrammatically at 58. This .pulse advances the position of-tl-ie electron beam of T-2 one step. Thus T-2 advances one step for every ten pulses on T-l as previously explained.

To avoid secondary emission to conical member D a cylindrical electrode F of higher positive potential than D may be employed.

Figure 6. illustrates an arrangement in perspective with certain parts schematic. Inthis form of the invention negative pulses to be counted are fed to terminals X and Y, through condenser 30, and the voltage is impressed across resistor 3|, which may be omitted. A power supply ;P. S. feeds electrode F and the deflection plates B. Associated with the deflecting plates are a series of resistors R-4 and R-5, the former being about 100,000 ohms each and the latter about 10,000 ohms each. Resistors R-l and R-Z may likewise be 10,000 ohms and Rr-3 75,000 ohms. These values of course depend on the size of the tube and voltage of the power supply but are given to show the order of magnitude. The several plates B may be energized by use of tubes 20 as shown electrons from 0-6 and be the most negative of all the several deflecting plates thereby leaving deflecting plate 3-6 the most positive of the group thus concentrating the beam of electrons on 0-6.

While the electron current intercepted by grid sector 0-6 and fedintothe symmetrical network of resistors Pr-4 and R-5 at plate B-l makes the potential of that plate a negative maximum with respect to itsinitial potential, it will be understood that part of this current also passes to plates B-2 and 13-!) through cross connecting resistors R-5 and displaces the potential of those plates negatively. In like manner all the pairs of plates B-3 and B-9; B-4 and B-8; B-5 and 38-1 and finally 3-6 are displaced negatively less and less as 3-0 is approached from B-l, The pairs of plates, by symmetry, are at equal poten-- tials, so that no deflecting electric field springs between them. The overall result is that a deflecting field arises between plates B-1 and B-6 substantially as if the other plates in the system were non-existent, and with 13-6 positive relative to B-!. The electron beam is thus deflected toward B-6 and is intercepted by grid sector 0-6 which through wire connection to 13-] maintains this condition of excitation after passage of the pulse. The potential distribution with this system is substantially the same as that described in connection with Figs. 5 and 9 but of opposite polarity. It is this reversal of polarity that requires plate B-l of Fig. 6 to be connected to the opposite grid sector 0-6 rather than to 0-! as in Fig. 9. In using the arrangement of Fig. 6 it will be understood that the current required in the electron beam must be appreciably greater.

than for Fig. 9 where the amplifying effect of the electron tubes 20 is utilized.

In connection with Figure 5, grid 0-! may become positive depending on the number of secondary electrons leaving C-l as compared to the number of primary electrons arriving at 0-l.

to the secondaries leaving 0-! can be controlled by the following variables: (a) shape, (b) material of the electrode, and (c) the intensity of the electric field at the surface of the electrode. If the number of secondaries are greater than the number of primary, C-I will become positive. In this case a cathode follower circuit should be used so as to give a positive potential to B-I.

I claim to have invented:,

1. The combination with a first electron gun for emitting a beam of electrons of a series of n deflecting plates located angular degrees apart and positioned about the path of travel of the beam of electrons, a conical deflecting electrode having the axis of the cone in line with the beam of electrons from said gun, said deflecting electrode being positioned within the field produced by said series of n deflecting plates, a lead-in wire for feeding the pulses to said conical deflecting electrode, a plurality of spiral shaped grid sectors positioned equally spaced from each other and concentric with the axis of said cone and farther from the electron gun thanthe cone, each of said spiral grid sectors making an oblique angle with a radius from the axis of the, cone to the grid, which if extended will intersect another of the grids, and an evacuated bulb surrounding all the above-named parts.

2. The device of claim 1 having in addition tion of the electron beam.

3. The device of claim 1 having in addition a fluorescent screen located on the evacuated bulb on the inside thereof and in a position to intercept the electrons passing through said grids.

4. The device of claim 1 having in addition a transfer grid extending through the bulb and perpendicularly to the axis of the cone.

5. The device of claim 1 having in addition a transfer grid extending through the bulb and per endicularly to the axis of the cone for a limited distance short of the axis of the cone.

6. In a counting device, an electron gun for projecting a beam of electrons initially along a given axis, a series of n equally spaced deflecting plates concentric with the axis and a short distance from the end of the gun in the direction away therefrom, a series of n spiral shaped overlapping grid sectors concentric with said axis and located farther from the gun than said deflecting plates, said spiral grid sectors extending at an acute angle to a radius from said axis to said grid, electrode means adapted to be energized by indicating means for indicating the angular posithe pulses to be counted for changing the radial angle of the electron beam emerging from said un whereby said beam is shifted radially from one spiral grid sector to another, and means connected to said grids and respective deflecting plates for holding the electron beam on any grid sector intercepting said beam.

7. In an electronic counting device, means for producing a beam of electrons, a plurality of deflecting plates acting electrostatically on said beam, an electrode within the field of said deflecting plates adapted to receive pulses, a symmetrical assembly of overlapping spiral grid sectors having openings therein, a. fluorescent screen having numerals thereon indicatingthe position of the electron beam, and means responsive to the electronic charge intercepted by the grid sectors connected to thecorresponding deflecting plates adapted to change the potential'thereof.

8. In anelectronic counting device, means for producing a beam of electrons, a plurality of deflecting plates adapted to act electrostatically on said beam, an electrode within the cylindrical space defined by said deflecting plates adapted to receive pulses to be counted, an assembly of overlapping spiral grid sectors having openings therein to pass electrons, a fluorescent screen havin numerals thereon to indicate the position of the electron beam, and vacuum tube means'responsive to the electronic charge intercepted by the grid sectors connected to the respective deflecting plates and adapted to change the potential thereof.

9. An impulse counting device comprising, an evacuated envelope having a fluorescentscreen on. one end thereof, an electron gun' within and at the other end of the envelope for producing a beam of electrons along the axis thereof, a plurality of deflecting plates arranged symmetrically around said axis, a cone-shaped electrode positioned on the axis in cooperative relation with the deflecting plates and adapted to be energized by the pulses to be counted, a plurality of electrically separate overlapping spiral grid sectors having openings therein to pass electrons, said grid sectors being aligned mom to one correspondence with said deflecting plates, numerals on said fluorescent screen to indicate the position of the electron beam, andcircui-t means connecting said grid sectors to the corresponding deflecting plates for concentrating the electron beam on any grid sector intercepting the beam.

10. In an electronic device forcounting pulses, means for projecting an electron-beam along an axis, a plurality of deflecting plates arranged symmetrically around the axis,a pulse receiving electrode positioned on the axis and within the field of the deflecting plates, a-corresponding plurality of spiral-shaped grid sectors so positioned that one sector partially intercepts the electron beam, means responsive to a change in potential quentially a corresponding one of said deflecting plates each time a pulse is received on said pulse electrode, and a fluorescent screen for indicating the position of the electron beam.

11. The structure of claim 7 in which the means responsive to the electronic charge intercepted by the grid sectors includes, separate resistors connecting each deflecting plate to a point of fixed potential, resistors connecting adjacent deflecting plates, and connections joining the respective deflecting plates to the correspondin opposite grid sectors.

12. The structure of claim 7 in which said overlapping spiral grid sectors have sufficient overlap that the beam of electrons is rotated one step in one direction in response to each positive pulse received on said pulse electrode and rotated in the opposite direction one step in response to each negative pulse.

ROBERT J. MOON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,932,637 Richardson Oct. 31, 1933 2,185,693 Mertz Jan, 2, 1940 2,186,388 Moritz, Jr. Jan. 9, 1940 2,200,745 Heymann May 14, 1940 2,202,527 Karolus et al May 28, 1940 2,204,055 Skellett June 11, 1940 2,241,809 Forest May 13, 1941 2,250,527 Gray July 29, 1941 2,250,528 Gray July 29, 1941 2,250,529 Gray et a1. July 29, 1941 2,290,651 Peck July 21, 1942 2,328,259 Christaldi et a1. Aug. 31, 1943 2,401,729 Goldsmith June-l1, 1946 2,404,106 Snyder July 16, 1946 2,404,920 Overbeck July 30, 1946 2,432,608 Desch et a1. Dec. 16, 1947

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