US2841741A

US2841741A - Multi-anode high speed switching tube

Info

Publication number: US2841741A
Application number: US566119A
Authority: US
Inventors: William C Wiley
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1956-02-17
Filing date: 1956-02-17
Publication date: 1958-07-01
Anticipated expiration: 1975-07-01

Description

July 1, 1958 w. c. WILEY 9 9 MULTI ANODE HIGH SPEED SWITCHING TUBE Filed Feb. 17, 1956 3 Sheets-Sheet 1 POWER SUPPLY INVENTOR.

WILLIAM C. WILEY I ATTORNEY July 1, 1958 w. c. WILEY 2,841,741

MULTI-ANODE HIGH SPEED SWITCHING TUBE Filed Feb. 17, 1956 3 Sheets-Sheet 2 24 22 20 ls l I I I I l I 26 \v/ 1 \1 v v v v is $1 %E@ 2 WILLIAM C. WILEY y 1953 .w. c. WILEY 2,841,741

MULTI-ANODE HIGH SPEED SWITCHING TUBE WILLIAM C. WILEY ATTORNEY aired States MULTI-ANODEHIGH SPEED SWITCHING TUBE Application February 17, 1956, Serial No. 566,119 6 Claims. (21. 315-12 This invention relates to a multi-anode high speed switching tube which utilizes crossed electric and magnetic fields.

For many applications it is highly desirable to switch the fiow of electrons so that they may be collected at any one of a plurality of anodes. Often, the switching action must take place with extreme rapidity, on the order of millimicroseconds, so that very little information is lost.

This invention provides such a high speed switch. A plurality of anodes are disposed in an evacuated envelope at a particular distance from an electrode. Crossed electric and magnetic fields are provided in the region between the anodes and the electrode so as to cause electrons to travel through the region in successive cycloidal paths. When a voltage is applied to a particular anode to re verse the electric field between that anode and the electrode, the electrons are directed towards and are collected by the preceding anode inthe plurality. In this way, the electrons may be switched to any anode by the application of a suitable voltage to the succeeding anode in the plurality. The switching action thus provided is very reliable and extremely rapid, on the order of 10 millimicroseconds.

An object of this invention is to provide a high speed electron switch.

Another object of this invention is to provide a switch in which electrons maybe directed to any one of a plurality of anodes.

A further object of this invention is to provide a switch of the above character comprising an evacuated envelope having a plurality of anodes disposed a particular distance from an electrode and crossed electric and magnetic fields provided in the region between the anodes and the electrode.

Still another object of the invention is to provide a switch of the above character in which electrons may be directed towards any anode by applying a suitable voltage to the succeeding anode in the plurality for modifying the electric field in the vicinity of the succeeding anode.

Other objects and advantages will become apparent from the following detailed description and from the appended drawings and the claims.

In the drawings:

Figure 1 is a perspective view, partly in block form, of the high speed switch constituting one embodiment of this invention.

Figures 2, 3 and 4 are schematic views of the tube shown in Figure 1 illustrating the electron flow in the tube under different conditions of operation.

Figures 5, 6 and 7 are schematic views of tubes incorporating certain modifications over the tube in Figure l and illustrating the resultant electron flow.

In Figure 1 an evacuated tube 10 is made of an insulating material such as glass. Disposed in the tube 10 is a source for emitting electrons such as a cathode 12 which emits electrons when it is heated. A screen grid 14 disposed in substantially parallel relationship to the atent ice cathode 12 at a relatively short distance from the cathode controls the-flowof electrons through the grid. An electrode 16- is positioned in laterally contiguous relationship to the grid 14.

A plurality of aligned anode plates 18, 2t), 22 and 24 are disposed in substantially parallel relationship to the electrode 16 to define a region between the plates and the electrode. A plate 26 is disposed in substantially perpendicular relationship tothe electrode 16 to receive any electrons flowing through the region between the electrode and the

plates

18, 20, 22 and 24.

The

plates

18, 20 and 22 have constant voltages of substantially equal magnitude applied to them from a power supply 28 through resistances 3t), 32 and 34, and through indicators such as

ammeters

31, 33 and 35, respectively. The

plates

24 and 26 also have voltages of substantially equal magnitude applied to them from the power supply 28, through resistances'36 and 33, respectively. For example, a constant voltage of zero magnitude may be applied to the plates 18, 2t}, 22, 24 and 26.

The power supply 28 also applies a constant voltage to the grid 14 through a resistance 40 and also applies constant voltages to the cathode 12 and the electrode 16. For example, 60 volts, 70 volts and volts may be applied to the grid 14', the cathode 12 and the elecnode 16, respectively. I

A cource of control voltage 42 is connected to the grid 14 to vary the potential of the grid 14 in accordance with the output of the source 42 so as to modulate the electron flow through the grid. The

plates

20, 22 and 24- are connected through

coupling capacitances

46, 48 and S0 to outputs of a voltage source 52 which may be set to apply a negative voltage such as 1OO volts to any one of the plates at a desiredtime for a particular period. The voltage source 52 may be of a type to pro vide a constant output or it may be of a type to provide a pulsed output, such as a square Wave output.

A pair of pole pieces 56 are positioned on opposite sides of the tube 10' to provide a magnetic field in the tube. The magnetic field is disposed vertically in Figure l and in a direction substantially perpendicular to the electric field in the regionbetween the electrode 16 and the

plates

18, 20, 22 and 24-. For example, the pole pieces 56 may provide a magnetic field of 300 gauss in the region between the plate and the electrode.

In operation, the electrons emitted by the cathode 12 pass through the grid 14. The number of electrons passing through the grid 14 is dependent upon the control voltage applied to the grid from the source 42. Be cause of the crossed magnetic and electric fields provided in the tube 10, the electrons passed by the grid travel in successive cycloidal paths as shown in Figure 2. During the period that constant voltages of substantially equal magnitude are applied to the plates 18, 2t), 22 and 24, the electrons travel through the region between the plates and the electrode 16 along an equal potential line and strike the plate 2 6 as shown in Figure 2.

When an output of volts is applied to the plate 24 from the source 52, the potential of the plate 24 becomes negative with respect to the electrode 16. This causes the electric field in the region between the plate 24 and the electrode 16 to become reversed. When this occurs the electrons are prevented from passing through the region and instead they follow a modified equal potential line to strike the plate 22 as shown in Figure 3 for detection by the ammeter 35.

Similarly, if the negative voltage is applied to the plate 22 from the source 52, the electrons are prevented from passing through the region between the plate 22 and the electrode 16 and the electrons are directed towards the plate 20 as shown in Figure 4. The electrons striking the plate 20 are detected by the ammeter 33. When the 3 negative voltage is applied to the plate 20 from the source 52, this modifies the electric field between the plate 20 and the electrode 16 and as previously described electrons are prevented from passing through thisregion and instead are directed towards the preceding v plate 18which they strike and are detected by the ammeter 31;

It will be noted that the electrons in the tube maybe collected by any one of the three

anode plates

18,20

in Figure 5. In effect, an electron multiplier is inserted between the switching region and the cathode 12 to multiply the electrons before their introduction to the switching region as shown in Figure 5. In this way, a high gain amplifier is compactly combined with a high speed electron switch in a single envelope.

In the modification shown in Figure 6, every other plate is used for a collector and field modifying voltages are applied to the plates succeeding each collecting plate. For example, if a voltage is applied to the plate 60 to modify the electric field in the region between the plate 60 L and the electrode 62, the electrons are received by the plate 64 as illustrated. Similarly, the electrons are received by the

plates

66, 68 and 70 when voltages are applied respectively to the

plates

72, 74 and 76. With this arrangement the collecting plates are electrically isolated to eliminate any distortion in the signal that may occur by the application of the modifying voltage to the collecting plate.

In a further modification shown in Figure 7, the electrons are diverted into another region preceding the plate to which a modifying voltage is applied. For example, when a voltage is applied to the plate 80, the electrons are directed into the region between the

plates

82 and 84 where they may be subsequently acted upon in any desired manner.

Although this invention has been disclosed and illustrated with reference to particular applications, the principles involved are susceptible of numerous other applications which will be apparent to persons skilled in tlie art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims. 7

What is claimed is:

1. An electron switch, including, a plurality of plates spaced from one another and disposed in substantial alignment, an electrode disposed relative to the plates to I 3 define a first region between the plates and the electrode, means for providing an electric field in the first region, means for providing a magnetic field in the first region in a direction substantially perpendicular to the electric field, the electric and magnetic fields being disposed in a direction and having a magnitude to cause electrons introduced to the region to travel completely through the region, and means for modifying theelectric field between a particular plate and the electrode to cause electrons introduced to the first region to be preventedfrom entering the region between the particular plate and the electrode. -l 2. An electron switch, including, a plurality of plates,

. the plates being spaced from one another insubstantially the same plane, an electrode disposed a particular distance from the plates in substantially parallelrelationship to the plates to define a first region between the electrode and the plates, means for applying substantially equal voltages to the plates for producing equal electric fields between each plate and the electrode, means for providing a magnetic field in the first region in a direction substantially perpendicular to the electric field, the com- 4 bined action of the magnetic and electric fields causing any electrons introduced to the first region to travel through the region without striking any of the plates, means for introducing electrons to the first region, and means for applying a voltage to one of the plates to reverse the electric field in the region between the plate and the electrode to prevent a passage of electrons through the region and to cause the electrons to strike the plate preceding, in the direction of electron travel, the plate to which the voltage is applied.

3. An electron switch, including, a plurality of plates spaced from'one another, an electrode disposed relative to the plates to define a first region between the plates and the electrode, means for applying voltages to the plates relative to the electrode to produce a substantially uniform electric field in the first region, means for providing a magnetic field in the first region in a direction substantially perpendicular to the. electric field, the combined action of the magnetic and electric fields causing any electrons introduced to the first region to travel through the region between the plates and the electrode, means for introducing electrons to the first region, means for applying a voltage to one of the plates to reverse the electric field between'the plate and the electrode to prevent a passage of the electrons and to cause the electrons to strike the plate preceding, in the direction of electron travel, the plate to which the voltage is applied.

4. An electron tube, including, an evacuated envelope, a plurality of plates disposed in the envelope in substantially aligned relationship, an electrode disposed relative to the plates to define a first region between the plates and the electrode, means for applying voltages to the plates relative to the electrode to produce an electric field in the first region, means for providing a magnetic field in the first region in a direction substantially perpendicular to the electric field, the magnetic and electric,

fields being disposed in a direction and having a magnitude to cause any electrons introduced to the region to travel completely through the region, means disposed in the envelope for emitting electrons, a grid disposed relative to the electron emitting means to provide for the passage of electrons into the first region and to control the flow of electrons in accordance with a control voltage applied to the grid, and means for applying a voltage to one of the plates in the plurality to modify the electric field so as to cause any electrons introduced into the first region to travel to the plate preceding, in the direction of electron travel, the plate to which the voltage is applied.

5. An electron tube, including, an evacuated envelope, a plurality of plates disposed in the envelope in substantially aligned relationship, an electrode disposed relative to the plates to define a first region between the electrode and the plates, means for providing an electric field in the first region, means for providing a magnetic field in the first region in a direction substantially perpendicular to the electric field, the electric and magnetic fields being disposed in a direction and havinga magnitude to cause any electrons introduced to the region to pass com- .pletely through theregion and past the plates, means in the envelope for emitting electrons, a grid disposed relative to the electron emitting means to pass the electrons and to modulate the electron flow in accordance with a control signal applied to the grid, an electron multiplier disposed in the envelope between the grid and the first region to multiply the electrons passedby the grid and to introduce the electrons to the first region, and means for modifying the electric field in the first region to cause the electrons to strike a particular plate.

6. An electron switch, including, a plurality of plates spaced from one another, an electrode disposed relative to the plates to define a first region between the plates and the electrode, means for providing an electric field in the first region, means for providing a magnetic field in the first region in a direction substantially perpendicular to the electric field, the electric and magnetic References Cited in the file of this patent UNITED STATES PATENTS Perkins Sept. 13, 1938 Linsell Jan. 30, 1940 Salzberg Feb. 3, 1942 FOREIGN PATENTS Germany July 23, 1953