US1941956A - System of electrodes for electric glow discharge tubes - Google Patents

Description

Jan. 2, 1934. G $518+ 1,941,956

SYSTEM OF ELECTRODES FOR ELECTRIC GLOW DISCHARGE TUBES Filed March 12, 1931 Fig. 1

Patented Jan. 2, 1934 PATENT OFFICE SYSTEM OF ELECTRODES FOR ELECTRIC GLOW DISCHARGE TUBES Georg Seibt, Berlin-Schoneberg, Germany Application March 12, 1931, Serial No. 522,123, and in Germany May 21, 1930 5 Claims. (Cl. 25027.5)

It is known in the art that in the case of glow discharges the cathode drop can be reduced when the cathode is constructed more or less as a hollow member. In this case several portions of the surface of the cathodes from which discharges take place face one another in some way or other.

A simple construction consists in this that two plates are arranged opposite one another at a distance of a few millimetres. In this case the main discharge current does not proceed from the surfaces which lie outside but substantially only from the surfaces which are opposite one another. The physical reason therefor is to be found in this that space discharges which tend to be produced at the cathode by positively charged ions, are dispersed by the electrons which proceed from the other surfaces of the hollow cathode.

The object of the present invention is to utilize the action of the hollow cathodes hereinbefore referred to in connection with the system of electrodes for glow discharge'amplifiers. Such a system consists, as is well known, of two discharge electrodes, viz, a cathode and an an- .ode, the discharge between which serves as a 1 siderably to increase the action of such glow discharge tubes so as to allow a greater yield in electrons for the amplifying current to be obtained with the reduction in the cathode drop, whereby the output of the amplifier is increased.

Various modes of carrying the. invention into effect are illustrated, by way of example, in the accompanying drawing in which Fig. 1 shows a form of cathode, Figure 2 is a modified construction thereof and Figure 3 is a cross-section of a complete system of electrodes for a glow discharge amplifying valve.

Figure 1 shows a hollow cathode, which consists of a sheet metal cylinder 2 provided with a longitudinal slot 1 through which the discharges can pass to the desired electrodes. The width of the longitudinal slot 1 may vary; it may be very small or so wide that it amounts, for instance, to half the peripheral surface of the cylinder. In order to impart a greater stability to the cathode, the same may be provided at its two ends with closing pieces 11 and d2, which may be made of metal or of insulating material. It is also preferable not to continue the longitudinal slot 1 right up to the edges at the ends of the cylinder but to stop short of these, as is illustrated in Figure 2. This also allows the mechanical stability of the cathode to be increased.

Figure 3 illustrates, by way of example, the manner in which the hollow cathode may be combined with a glow discharge amplifying tube. It will be seen that in this arrangement, which is illustrated in cross-section, the amplifying anode az lies in the axis of a concentric system. The amplifying anode is shown as being surrounded by a cylindrical coil constituting the controlling electrode .9. In its turn the latter is concentrically surrounded by the discharge anode or, preferably consisting of a cylinder from which longitudinal strips have been cut out so as to form openings through which the electrons coming from the glow discharge field can be drawn into the actual amplifying space. In contradistinction to the arrangements hitherto proposed, the cathode is not constituted by a plurality of individual strips or wires arranged behind the solid parts of the discharge anode but by individual small cylinders k: which have a diameter of a few millimetres, for instance 3 mms. Their length is equal to the length of the other electrodes, that is to say several centimetres. In order to retain the screening effect of the discharge anode described in my prior applications concerning glow discharge amplifying tubes, the 90 individual parts 1c of the hollow cathode are preferably so dimensioned and arranged that they are completely screened. However, presumably it would not be dangerous if a straight line path proceeded from the outer walls of the individual cathode parts to the amplifying electrodes, since owing to the action of the hollow cathode is hereinbefore described, only that part of the discharge is mainly effective as regards the average yield in electrons, which pass-through the slotlike openings 1.

If required, the outer walls of the cathode cylinder may be surrounded by insulating material, which prevents any discharge taking place from these parts.

It is to be understood that the position of the slots 1 ofwhich two are provided in each cylinder, may be varied and that they may be displaced relatively to one another to a certain extent.

As stated at the outset, the glow cathode may trodes consisting of a cathode an'd'an an'cde,;the i discharge between which serves as a source'ofelectrons, a second anode to which an amplification current passes from the saidsource of electrons and a controlling electrode which modu-.

lates the said amplification current, said first anode being constructed and arranged as a solid shield between said cathode and said controlling electrode, the individual parts of said cathode being constructed as hollow cathodes in the form of cylinders having longitudinal openings.

2. A system of electrodes for glow discharge amplifying tubes comprising two discharge electrodes consisting of a cathode and an anode, the discharge between which serves as a source of electrons, a second anode to which an amplification current passes from the said source of elecoftrons and a controlling electrode which modulates the said amplification current, the individual parts of said cathode being constructed as hollow cathodes, in the form of cylinders having longitudinal opening-s, which terminate just .before the edges at the ends of the said cylinders. .3. A system of electrodes glow discharge amplifying tubes comprising two discharge electrodes consisting of a cathode and an anode, the discharge between which serves as a .source of 9 i'electrons, a second-anode to which an amplification current passes from the said source of electrons and a controlling electrode-which modulates the said amplification current, the indiand the outer walls of said hollow cathodes vidual parts of said cathode being constructed as hollow cathodes, in the form of cylinders having longitudinal openings which terminate just before the edges at the ends of said cylinders, and members of insulating material covering the ends of said cylinders.

,4. A system of electrodes for glow discharge amplifying tubes comprising two discharge electrodes consisting of a cathode and an anode, the discharge between which serves as a source of ,electrons, a second anode to which an amplification current passesfrom the said source of electrons and a controlling electrode which modulates the said amplification current, the individual parts of glow cathode being constructed as hollow cathodes, said hollow cathodes being in 'the'form'of cylinders having longitudinal openings which terminate just before the edges at the ends of the cylinders, and members of insulating material, covering the ends of the cylinders the surfaces of said hollow cathodes which take part in the discharge being covered with a substancethe cathode drop of which is small.

5. A system of electrodes for glow discharge amplifying tubes comprising two discharge electrodes consisting of a cathode and an anode, the discharge between which serves as a source of electrons, a second anode to which an amplification current passes from the said source of electrons and a controlling electrode which modulates the said amplification current, the individual parts of said cathode being constructed as hollow cathodes, said hollow cathodes being in the form of cylinders having longitudinal openingswhich terminate just before the edges at lfi the ends of the cylinders, and members or insulating material covering the ends of the cylinders, the surfaces of said hollow cathodes which take part in-the discharge being covered with a substance the cathode drop of which is small,

being covered with insulating substances.

. i GEORG SEIBT.

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