US3110838A - Glow discharge counter tube - Google Patents

Description

Nov. 12, 1963 H, VON IGUGELBERG ,8

GLOW DISCHARGE COUNTER'TUBE Filed Jun so, 1960 United States Patent 3,110,838 GLOW DISCHARGE C(IUNTER TUBE Hans Luz von Gugelberg, Schloss Salencgg, Mlaienfeld, Switzerland Filed June 36 1960, Ser. No. 39,849 Claims priority, application Switzerland Dec. 9, 1959 5 Claims. (ill. 313-196) This invention relates to glow-discharge counter tubes and more particularly to glow-discharge counter tubes comprising an envelope filled with a gas containing or consisting of hydrogen.

Glow-discharge counter tubes are known wherein a large number of strip-shaped or rod-shaped cathodes are arranged in a straight or circular row. Under the influence of electrical impulse voltages, the glow discharge always jumps over from one cathode to a neighbouring cathode, all the cathodes have been arranged, each in the same sense, obliquely to the longitudinal direction of the row of cathodes, and the anode has been constructed in such a manner that one end of the cathodes is directed towards the anode and the other end of the cathodes is directed away from said anode. In order to reverse the direction of counting as desired, two anodes have been provided, parallel or concentric with one another, and the straight-lined cathodes have been so arranged in the space between these anodes, obliquely to the longitudinal direction of the anodes, and so dimensioned that one end of the cathodes is adjacent to the one anode and the other end is adjacent to the other anode. Glow-discharge counter tubes of this type, with the usual filling of rare gas, function satisfactorily and the external operating conditions are not very critical.

Themaximum counting speed at which the glow-discharge tube still works reliably is comparatively low when the tube is filled with rare gas and amounts to about kilocycles per second, for example, with the usual neon filling. In glow-discharge counter tubes with the electrode arrangements of the type described above, the maximum counting speed is determined in practice only by the ionization and deionization times. Now it is also known that in a hydrogen glow-discharge, the ionization and deionization times are much shorter than in a rare gas glow-discharge because of the much greater ionic mobility. Also responsible for this phenomenon is the fact that, in hydrogen, a considerable proportion of the electrons is produced at the cathode by photo-electric means by the cathode glow. In view of such considerations, therefore, the rare gas filling should be wholly or at least partially replaced by hydrogen in order to increase the maximum counting speed in glow-discharge counter tubes accordingly. If hydrogen is mixed with rare gas in a glow-discharge counter tube with a given arrangement and construction of the tube electrodes, however, the stable discharge phenomena which previously occurred disappear with even a small proportion of hydrogen with otherwise equivalent electrical and gaskinetic conditions. The glow tends to jump in an uncontrollable manner from individual cathodes to other cathodes or to the insulating members of the tube which are almost inevitably covered with a thin layer of atornised metal. With pure hydrogen discharge, these disturbances are particularly marked and the increase in the counting speed theoretically possible by means of filler gases containing or consisting of hydrogen could not be realised in practice hitherto, or at most only partially, for these reasons.

The present invention aims at overcoming the disturbances briefly mentioned above when a filler gas containing or consisting of hydrogen is used. Objects of the invention is a glow-discharge counter tube comprising an envelope filled with a gas containing or consisting of hyanodes.

drogen, a plurality of hookor loop-shaped cathodes and one or two anodes inside said envelope, said cathodes are arranged side-by-side in a row and are oriented, each in the same sense, obliquely to the longitudinal direction of said cathode row, in such a manner that one end of said cathodes is directed towards an anode while the other end of said cathodes is directed away from the same anode, the opening in the hook or loop of each cathode is orientated in such a manner that, from each cathode, it is possible to see a part of said anode through the opening in the hook or loop of the following cathode in the direction of counting. An object of the invention is to provide, in a glow-discharge tube of the kind outlined, separate pins for each of said hookor loop-shaped cathodes, said pins consisting of a material which has a higher cathode fall potential than the material of which said cathodes are made. A still further object of the invention is a glow-discharge counter tube of theconstruction mentioned above, wherein the pins of all said hookor loop-shaped cathodes are secured in an insulating support, and this insulating support comprises, on the surface facing said cathodes, depressions through which said pins pass concentrically.

These and other objects and the advantages of the invention will best be understood from the following description of specific embodiments when read in connection with the accompanying drawing in which:

FIG. 1 is a cross-section through a glow-discharge counter tube with a plan view of all the tube electrodes, the tube having two anodes and a reversible counting direction;

FIG. 2 is a section parallel to the tube axis at the line 22 in FIG. 1, affording a front view of a loopshaped cathode used, and showing a section through the insulating support in which the pin of the cathode is secured, and

FIG. 3 is a section corresponding to FIG. 2 with a front view of a hook-shaped cathode.

Extending inside the tube envelope 4, which is shown in cross-section in FIG. 1, are two circular anodes 5 and 6 which are concentric with one another and which may either be wire rings or short sheet-metal cylinders. In the annular space between these anodes there are provided the cathodes 7 to 16 arranged oircumferentially about the inner anode *5 and which are equally spaced from each other and which are similarly, obliquely oriented with respect to the circumferential direction of said The inner ends of the cathodes 7 to 16 are directed towards the anode 5 while the outer ends of the cathodes 7 to 16 are directed away from the anode 5. On the other hand, the outer ends of the cathodes 7 to 16 are adjacent to the outer anode 6 while the inner ends of the cathodes 7 to 16 are remote from the anode 6. If the inner anode 5 is in operation, the direction of count ing is in counterclockwise direction; when the outer anode 6 is in operation, the counting is in a clockwise direction.

Although, with the tube envelope 4 filled with rare gases, the cathodes 7 to 16 can consist of simple stretched wires or bands, when a gas containing hydrogen is used it has been found necessary to give the cathodes 7 to 16 the form of a hook or a loop as shown in FIGS. 2 or 3, in which case, naturally, the precise formation of the hook or loop may vary to a large extent. The symmetrical construction of each of the cathodes 7 to 16, as shown in FIG. 2, is preferably used in glow-discharge counter tubes with two anodes 5 and 6 and with a reversible counting direction. If only one counting direction is required, the anode 6 for example may be omitted and the cathodes 7 to 16 may then conveniently be of the hook-shaped construction shown in FIG. 3. In both constructions the opening 17 in the hook or loop (FIGS. 2 and 3) of all the cathodes is orientated in each case in such a manner that from the outer end of the cathode 7 for example (FIG. 1) it is possible to see a part of the effective anode 5 through the opening in the hook or loop of the succeeding cathode 16 in the direction of counting. Conversely, however, in a tube having two anodes 5 and 6, from the inner end of the cathode 15, for example, it is possible to see a part of the outer anode 6 through the opening 17 in the hook or loop of the cathode 16 (FIG. 1). The distance between the two parallel limbs of the hook '(FIG. 3) or the loop (FIG. 2) is preferably short in relation to the length of the limbs. Furthermore, this distance between the limbs should be related to the gas pressure of the filler gas in such a manner that the negative glow light can just extend inside the opening 17 in the hook or loop. The glow light will then prefer this region because of a slight hollow-cathode effect and will have less tendency towards uncontrolled jumping away. With correct dimensioning, the visual maximum brightness of the negative glow light is seen in the form of an elongated zone which extends substantially in the middle between the two parallel limbs of the hookor loop-shaped cathode and which is slightly displaced, as a whole, towards the anode which is in operation. Apart from this, the operating conditions are preferably selected in such manner that the particular cathode which is glowing is covered with glow light substantially over its whole length. In these circumstances there is a stabilization of the glow light on the individual cathodes, which is still efiective even when considerable proportions of hydrogen are used in the filler gas. At the same time, a powerful preionization is obtained in the region of the cathode which follows in the direction of counting and this has a favourable effect on the counting speed which can be attained.

The hook or loop of the cathodes can be obtained not only with Wires but also with sheet metal. In this case, the actual plane of the metal may be bent into the form or" a hook or loop, or the sheet metal may be stamped out in the form of a hook or loop and arranged on edge in the sense of FIGS. 2 or 3. If only one direction of counting and hence only one anode is required in the tube, then the possible variations in the cathodes which are hook-shaped in principle, is considerably greater. For example, it is not absolutely necessary for both limbs of the hook to run parallel; instead, one limb may be bent up to a greater or lesser extent; and one limb may be longer or shorter than the other limb. With sheet metal or bands bent into U-shape or V-shape, serviceable cathode shapes are likewise obtained which are derived from the hook shape and which permit a stabilization of the negative glow light depending on the pressure and the composition of the filler gas containing hydrogen.

Independently of the precise construction of the hookshaped or loop-shaped cathodes 7 to 16, it has further been found advisable to secure the cathodes 16 (FIGS. 2 and 3) to pins 18 which have a higher cathode-fall potential than the cathodes 16 so that the glow discharge shows little tendency to spread from the cathodes 16 to the pin 18. For this purpose, the cathodes 16 may be made of molybdenum Wire, for example, and the pins 18 of nickel wire. The connection of the cathodes 16 to the pins 18 is usually effected by welding and in the drawing the welding point is indicated at 19. In the usual tube constructions, the pins 18 are secured in an annular insulating plate 20, which also serves to hold the anodes 5 and 6 and which is guided in the tube envelope 4. The insulating plate 20 may consist of a material on a ceramic base and the pins 18 are secured, for example, by means of cement. On the surface adjacent to the cathodes 16, the insulating plate 20 comprises depressions 21 (FIGS. 2 and 3) which are preferably cylindrical and the pins 18 traverse these depressions 21 with adequate radial clearance. The dimensions of the depressions 21 are such that the glow light cannot develop inside said depressions 21, even if it should pass over to the pins 18. If all these measures are observed, stable discharges are obtained with the tube described even with a filling of pure hydrogen and maximum counting speeds of more than two megacycles per second are attained.

The glow-discharge counter tubes described can be used in practically any of the known circuits which are suitable for high counting speeds. For example, the impulses to be counted may be super-imposed on the potential of the anode in question, in which case a resistor which is bridged by a capacitor is introduced into the circuit of each of the cathodes. It is also possible, however, depending on the desired direction of counting, to connect the anode in question to the positive pole of the voltage source through an anode resistance, to connect all the even-numbered cathodes to the negative pole of the voltage source and to apply the impulses to be counted to the remaining odd-numbered cathodes jointly. These and other modifications which may occur to those familiar with the art fall within the scope of the invention as set forth in the following claims.

I claim:

1. A glow discharge counter tube comprising an envelope filled with a gas containing hydrogen, a circular anode located within said envelope, a plurality of equally spaced cold cathodes within said envelope, said cathodes being arranged circumferentially of said anode being equally spaced therefrom, each of said cathodes having a hook-shaped portion comprising two substantially parallel limbs and a curved connecting piece, and means holding the end of one limb of each of said cathodes in such a manner that said curved connecting piece is nearest said anode and said limbs of each of said cathodes point away from said anode in a direction which is oblique t0 the circumference of said anode.

2. The invention as recited in claim 1, wherein said means holding said cathodes are pins consisting of a material which has a higher cathode-fall potential than the material of which said cathodes are made.

3. The invention as recited in claim 2, wherein said pins are secured in an insulating support having depressions on its surface facing said cathodes through which said pins pass concentrically.

4. A glow discharge counter tube comprising an envelope filled with a gas containing hydrogen, a pair of concentric circular inner and outer spaced anodes in said envelope, a plurality of equally spaced cold cathodes arranged circumferentially about said inner anode in the annular space between said anodes and coplanar therewith, each of said cathodes having a ring-shaped portion comprising a pair of substantially parallel limbs and a pair of curved connecting pieces, the limbs of each of said cathodes extending in a direction which is oblique to the circumference of said anodes, and means for holding said cathodes in such a manner that one of said two curved connecting pieces of each of said cathodes is nearest one of said anodes and the other of said curved connecting pieces of each of said cathodes is nearest the other anode.

5. The invention as recited in claim 4, wherein said means for holding said cathodes comprise pins made of a material having a higher cathode-fall potential than the material of which said cathodes are made, said pins holding one limb of each of said cathodes substantially in the middle between said two connecting pieces.

References Cited in the file of this patent UNITED STATES PATENTS 2,598,677 Depp June 3, 1952 2,635,810 Townsend Apr. 21, 1953 2,790,110 Applegate Apr. 23, 1957

Claims (1)

1. A GLOW DISCHARGE COUNTER TUBE COMPRISING AN ENVELOPE FILLED WITH A GAS CONTAINING HYDROGEN, A CIRCULAR ANODE LOCATED WITHIN SAID ENVELOPE, A PLURALITY OF EQUALLY SPACED COLD CATHODES WITHIN SAID ENVELOPE, SAID CATHODES BEING ARRANGED CIRCUMFERENTIALLY OF SAID ANODE BEING EQUALLY SPACED THEREFROM, EACH OF SAID CATHODES HAVING

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