US2921220A - Pulse distributing devices - Google Patents

Description

Jan. 12, 1960 J. M. N. HANLET PULSE DISTRIBUTING DEVICES Filed Jan. 8, 1957 FlGA FlGZ

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T 2' a (e) a H6 3 United States PatentO 2,921,220 PU'LS" EDIST RI B'U G'D'EVI'CES Jacques Marie Noel Hanlet, Paris, France, assignor to Societc dElectronique, et d Automafisme, Courbevoie, France The present invention relates to improved ste'p by-ste'p electrical pulse distributors of the kind wherein a series ofincoming" electrical pulses is applied incommon to all the distributing stages and wherein these stages are so interconnected as to automatically ensure a progression by one step of the activeoutput for each incoming" pulse.

An object of the invention is' to so" provide a pulse distributor of the above specified kind capable of operating' at a very high speed to deliver at the outputs thereof current pulses of high values with respect to the current amplitude of the incoming pulses for instance the ratio of output to input" currents being of the order of 100 to I or evenhigher.

A- further object of the invention is to provide a pulse distributor of such a kind and erformance which makes use of trio'de discharge paths as elementary stages thereof.

A further object of the invention to provide a completely built-in structure" ofsuch a pulse distributor.

According to the invention, such a pulse distributor comprises 'in combination a plurality of separate discharge paths within gas or vapour, each path being determinated by a cathode, an anode and a control electrode, acommon battery supply for the anodes, separate output leads from the cathodes,- a common input wire for the control electrodes and separate coupling capacitors for connecting. the said control electrodes to such wire, means for capacitively coupling the cathode of each path to the cathode of the next following path in the distributor sequence and means for resistively coupling the cathode of any path to the control electrode of the next following path in the said distributor sequence.

According to the invention further, and in a preferred embodiment thereof, such a pulse distributor is formed within a single vapour or gas vessel as an assembly of alternate cathode and dielectric coupling-element washers, a conducting rod acting as a common anode and a further rod bearing coaxial condenser couplings being transversely provided for acting as a combined common input wire, coupling condenser and control electrodes for the said cathodes and common anode rod.

Reference will be made to the accompanying drawings wherein:

Fig. 1 shows graphs characteristic of a pulse distributor according to the invention; A

Fig. 2 shows the electric scheme of the said pulse distributor; and

Fig. 3 shows the construction of a preferred embodiment of a pulse distributor according to the invention.

The pulse distributor comprises, Fig. 2, a plurality of vapour discharge paths I, II, III, IV each of which is defined by the combination of a cathode 2, an anode 3' and a control electrode 4, within an identical volume of gas 1. An output lead 11 is connected to each cathode 2. In the drawing it is shown as feeding a common output lead 12 through individual output leads 9. This arrangement ensures the connection of earth to each of the cathode leads 9.

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A common input rod or wire 10 receivesthe series of pulses such as' shown at E in Fig. 1.. This seriestof pulses may or may not be of a fixed frequency, according to the purposes of the device. However, it will herein be assumed that the pulses are regularly spaced and applied to the wire 10 so that a distribution cycle occupies a time interval T. At the end of each set of N pulses, the distributor will be reset to a predetermined starting condition. In each' set, the first pulse will the the first discharge path I, the second the discharge path II, and so forth. Each pulse at the output of a cathode will last a complete time interval between two actuating pulses. Of course, the graph of Fig. 1 is not quantitative. The amplitude of the output pulses is to be understood as being at least one hundred times the amplitudeof an input pulse. i

The input lead 10' is capacitively" coupled, through condensers 6 to the control electrodes 4. mon anode lead 5 applies high voltage supply +HT to anode 3. In the embodiment of Fig. 2', relating to a straight line distributor, the first control electrode is supplied with a DC. voltage from a voltage divider 13-14 supplied from the said +HT supply. Consequently the voltage ofthe control electrode will be-maintained at such a value that the first pulse will fire the first path I of the distributor. If, on the otherhand, the distributor was to be operated as a ring distributor, the control electrode of the first discharge path thereof will be connected to the cathode of the last discharge path thereof, in a similar way as are coupled any two successive cathodes and control electrodes in the distributor.

Each cathode is coupled to the next following one by a capacitive coupling 7. It is further connected to the control electrode of the next discharge path through a resistance 8. When a pulse occurs at 10, the path which was ionized will be deionized as the next following path will become ionized.

In a straight line distributor, the last stage would remain activated at the end of the set of pulses. To prevent this a negative pulse is inserted between the positive pulses each time N positive pulses have been sent (N being the number of pulses in a cycle T). The last stage then serves only to ensure the return to rest of the N-l the discharge path;

A pulse distributor according to the invention is made as follows: See Figs. 3a to 3 7 Each one of the cathodes 2 is formed as an annular washer with two opposite extensions 16 and 17. The extension 17 is slotted to receive and grip an output connection 11 whenthe cathode is placed within the vessel 28 common to all the elements of the said tributor. In at least two other places of the periphery of a cathode washer, slots are provided for the purpose of centering the washer within the vessel by means of insulating supporting rods within the vessel 28. In the inner edge of a cathode washer, a further slot is made for accommodation of a control electrode as will be later described. The material used for the cathode washers may be nickel, and the thickness may be about 1 millimetre.

The other elements of each cathode assembly are washers such as 18, shown in Fig. 3b and 23, shown in Fig. 30. Each washer may be of mica or ceramic material and for instance of about 7 to 8 microns in thickness. Each, of such washers also has the same extensions as the cathode washers. The washer 18 is provided with two such extension 19 and 20, the latter being slotted; the washer 23 is similarly provided with the extensions 24 and 25, the latter being slotted. A pair of such The" com- "washers are set between each pair of cathodes in the 'assembly.

Both kinds of washers are perforated at their centers to support a common anode rod 3 passing therethrough. They are further perforated at 22 to receive the control .eieeoedeser the structure. The rod 3 may be made of iiickel. r In an illustrative example, this rod will have a diameter equal to 4.5 millimetres whereas the inner :diameter of the cathodes will be equalto 17 millimetres. On each insulating washer such as 18 is printed a resistance 8 connecting the cathode to the control electrode of the next following stage: actually this resistance is the resistance 8 of Fig. 2. This is quite feasible as in the concerned example, this resistance must be of the order of 300 kilohms, (120%). For instance, the res istance is established by depositing on the washer and along the path clearly shown in Fig. 3b a mixture containing 7 parts per weight of a silicon resin and 1 part ,of colloidal carbon. This paint will also cover the edge of the extension 19 of the washer 18. The washers are baked during three hours for instance at 220 C. until .the resistance is quite stabilized.

When assembling the washers, the face of 18 which ..bearsthe lower part of the resistance is applied to the cathode washer of the next preceding stage and then an ,insul ating washer 23 is placed over the washer 18 and a further cathode washer and so forth. The upper part of .the resistance 8 will contactthe control electrode of the said next following path which is formed annular to a rodwhich is forced through the assembly. As more clearly shown in Fig. 3d, all the control electrodes are ;made as such deposits over a conducting rod 10 which ,hasbeen previously coated with an insulating film 32. For instance, the rodis of aluminium and the dielectric coatingthereon ismade of aluminium oxide. The control electrodes are made thereupon as deposits of silver, 1 platinum or carbon and simultaneously constitute the condensers 6 of Fig. 1. When carbon is used, the deposition maybe effected from a colloidal carbon suspension within isopropylic acid or alcohol. When platinum is -used,.the deposition is effected from platinum tetrachloride. When silver is used, the deposition will be made fromamixture of powdered silver and glass flux which is heated thereafter. -In each case, it is easily feasible to I obtain such coupling capacities as requested,-viz. of the order of 400 picofarads.

a The assembly, guided by means of insulating rods such '-as 30, of Fig. 3f, defines a plurality of discharge paths each of which has a Width equal to that of a cathode washer. Preferably the coaxial anode rod is spaced from the inner diameter of the cathode by about five times the spacingbetween the outer diameter of the cathode and the control electrode thereof.

The assembly may be formed as follows: the rods 3 and 10 (this latter bearing the condensers and control electrodes) are first sealed in an insulating base 27, and a spacing washer 33 is positioned as shown to serve as ,an abutment surface for the further assembly. A first washer 1.8 is then put into place, then a washer 23, a cathode washer and so forth. The assembly is terminated by a cathode washer if the distributor is tobe of a straight line type or upon a washer 18 in the case of Ia ring distributor (not contacting the control electrode member but'connected to an output wire for connection thereof to the control electrode of the first stage). The piling will be guided by means of insulating rods such as 30, for instance also sealed in the base 27. Then a glass or ceramic tube 28 is passed over the assembly and sealed to the base plate 27. The tube 28 is slotted along j a portion thereof so that when sealed, a corresponding slot exists in front of the parts such as 172025 of the washers. Short rods or tabs are placed at 11 and the "slot is filled with athermosetting resin, for instance an ethoxylin resin.

Prior to the assembly, and immediately after the first washer has been put into place, the resistive coating of the said washer has been soldered to an output wire 15 sealed in the base plate 27. This first washer may be made, when required so as to have a resistive coating extending up to the anode rod so as to obtain the resistances 1314 of Fig. 2. The point of soldering of the wire 15 will then be so chosen as to provide a ground lead in such a case.

After sealing the vessel, as herein above said, it is evacuated through 31 and thereafter filled with a gas such as helium under a pressure equal to several millimetres of mercury. However, a small percentage of hydrogen, of the order of 3 to 5% may be provided within the said helium atmosphere.

It is apparent that such a built-in distributor is compact and robust. More specifically the width of the discharge paths therein is considerably reduced so that a material having a high power of extraction, such as nickel, may be used for the cathodes, thus eliminating stray phenomena such as photoelectric or secondary emissions therein. The distances to he travelled by the ions will also be considerably reduced and consequently the speed of distribution may be very high though using discharges within a gas atmosphere.

What is claimed is:

l. A high speed distributor of electrical pulses comprising a single envelope containing an ionizable gas at low pressure and having enclosed therein a plurality of cathodes and cooperating anode means forming a plurality of separate discharge paths, said cathodes being in the form of a coaxial assembly of conductive washers, a pair of dielectric spacers interposed between each pair of cathode washers, said anode means comprising a common conducting rod extending coaxially through said .washers'and spacers, a second conductive rod extending through said washers and spacers eccentrically of the assembly and being coated with a dielectric layer, said second rod having spaced conductive coatings on the dielectric layer, the second rod forming a common pulse input lead, said coatings in cooperation with said second rod forming a plurality of spaced capacitors, said conductive coatings also forming control electrodes for the discharge paths, and a resistance connection between each cathode washer and an adjacent conductive coating.

2. A pulse distributor according to claim 1 wherein each cathode washer is slotted for accommodating without direct galvanic connection therebetween one of the cylindrical coating control electrodes and each of the dielectric washers which bears the said resistive film is perforated to receive one of the said cylindrical control electrode whilst ensuring an electric connection between the film and the control electrode.

3. A pulse distributor according to claim 1 and wherein the said input rod is of aluminium, coated with aluminium oxide and the said cylindrical control electrodes are deposited upon said oxide coating.

4. A pulse distributor according to claim 1 and wherein the gas is helium including a small percentage of hydrogen.

5. A pulse distributor according to claim 1 wherein a conductive film is made upon one of each pair of spacing dielectric washers of the assembly for constituting the interconnecting resistances from each cathode in the assembly to each following control electrode.

6. A pulse distributor according to claim 5 and wherein each conductive film is made by deposition of colloidal carbon on both faces and the edge therebetween of an extension of the dielectric washer, the said coating being of the height of the radial dimension of a cathode washer on one face thereof and of a height sufficient for ensuring electrical connection to the sai control electrode on the other face thereof.

7. A pulse distributor according to claim 1 wherein References Cited in the file of this patent each cathode washer has an extension which is slotted, a metal stub secured in the slot passing through the in- UNITED STATES PATENTS Sulating wall of the said envelope and acting as a cath- 2,443,407 Wales June 15, 1948 ode output lead therefor. 5 2,454,782 Rosa Nov. 30, 1948 8. A pulse distributor according to claim 7 in which 2,524,115 Mumma Oct. 3, 1950 the periphery of the envelope is slotted longitudinally 2,633,550 Stieritz Mar. 31, 1953 thereof in registry with the slotted extensions of the 2,651,006 Mederos Sept. 1, 1953 cathode Washers, said stubs extending through the slot, 2,687,487 Webster Aug. 24, 1954 and dielectric sealing material filling said slot. 10 2,730,658 Six Ian. 10, 1956

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