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US3248603A - Mean free path gaseous discharge tube and circuit thereof - Google Patents

Mean free path gaseous discharge tube and circuit thereof Download PDF

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Publication number
US3248603A
US3248603A US126364A US12636461A US3248603A US 3248603 A US3248603 A US 3248603A US 126364 A US126364 A US 126364A US 12636461 A US12636461 A US 12636461A US 3248603 A US3248603 A US 3248603A
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electrodes
electrode
switch
gas
trigger
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John F Howell
Ralph H Kalb
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General Electric Co
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General Electric Co
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Priority to DEG34933A priority patent/DE1238540B/de
Priority to GB17858/62A priority patent/GB1012728A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T2/00—Spark gaps comprising auxiliary triggering means
    • H01T2/02—Spark gaps comprising auxiliary triggering means comprising a trigger electrode or an auxiliary spark gap
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J17/00—Gas-filled discharge tubes with solid cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0059—Arc discharge tubes

Definitions

  • This invention relates to a high voltage, high current switch, and particularly to such-a switch, the operation of which is free of any moving parts.
  • the triggered spark gap is an arc discharge device that functions as a high voltage switch; it employs the electrical breakdown or ionization of a gas Within the tube in order to provide conduction.
  • the triggered spark gap is a tube, the interior of which is filled with a gas which is capable of ionization (i.e., the breaking down into ions and electrons of an otherwise electrically neutral gas) when a sufliciently large voltage is applied between the two main electrodes.
  • the triggered spark gap comprises three electrodes; two of them, the two main electrodes, act as the figurative contacts of the switch, and the third acts to close this elemental switch by virtue of breaking down or ionizing, with a preparatory or initiating pulse, the gas disposed between the third electrode and one of the two main electrodes.
  • the third electrode is spaced much more closely to one of the two main electrodes than are the two main electrodes spaced from each other. This close spacing is the reason why the potential applied between the third electrode and one of the main electrodes causes ionization with a smaller potential than that which would be required to break down the gas between the two main electrodes.
  • the two main electrodes which act as the contacts of the switch, are disposed opposite one another and are spaced from each other (insulated from each other) by a distance which is appropriate for the voltage of interest. That is to say, it is appropriate in the sense that conduction between the two main electrodes will not occur for the potential of interest that is applied across the two main electrodes without the aid of the action of the third electrode.
  • the third or trigger electrode projects just through, and is insulated from, the surface of one of the two main electrodes. When the spark gap is to be switched, a short electrical pulse of suitable polarity is applied between the trigger electrode and the adjacent main electrode. This difference of potential is suflicient to break down these two closely spaced electrodes, whereby ionization takes place therebetween, thus allowing the main discharge to occur between the two main electrodes.
  • the ionized particles tend to move toward the negative main electrode, while the electrons standing of the operation of the instant invention.
  • the pressure of the gas within the tube which serves the function of ionizing, and thereby forming the conductive path ranges between one-half and one atmosphere of pressure. Under these circumstances, than, a large number of gas molecules and charged particles move at random between the two main electrodes. After the initial ionization caused by the breakdown between the trigger and one main electrode has occurred, the electrically charged particles tend to move in the direction of the electrode of opposite polarity. In moving to the oppositely poled electrode, however, they encounter other particles both charged and uncharged.
  • the uncharged particles may be the molecules which have not yet been ionized. Because the motion of the particles before ionization is quite random, and because the molecules subsequent to ionization are dispersed at different points in the volume between the two electrodes, there is a very large probability that these charged particles, moving to their oppositely poled electrode, will be deflected from their straight line path to the electrode, either physically by an uncharged molecule, or electrically by a charged particle. This will hamper the completion of the conductive path between the electrodes.
  • the mean free path In the pressure range used for triggered spark gaps, approximately one-half to one atmosphere of pressure, the mean free path of a charged particle within the gap is much less than the physical distance between the two main electrodes.
  • the average delay between applying the triggering pulse and completing the conduction path, that is, firing the gap may vary between .1 microsecond and tens of microseconds, depending upon the voltage applied between the main electrodes.
  • the smaller delay time is attributable to higher voltages, since the momentum of the charged particle is greater due to the higher voltage; the particle is therefore less likely to be deflected substantially by other particles.
  • the switch of the invention experiences no measurable delay at all.
  • the application of a triggering pulse results in an instantaneous completion of a conduction path between the two main electrodes.
  • the expression mean free path is obviously a statistical parameter, one can except the actual free path to vary in magnitude about the value of the mean free path. Consequently, the actual delay varies in length with successive closings of the switch.
  • the successive delays may vary as much as twenty-five percent about that figure with successive firings.
  • This variation in the length of delay with successive pulsing of the spark gap is termed jitter. Jitter is also a function of applied voltage, and in the triggered spark gap may range from .05 microsecond at the optimum applied voltage to several microseconds with an applied voltage only a couple of hundred volts away from the optimum applied voltage.
  • a triggered spark gap designed to switch for example, ten kilovolts, may operate with increasing jitter and unreliability down to about five or six kilovolts. Below that, however, no switching action occurs at all. Therefore, the approximate range of the supply voltage that can be expected for switching a triggered spark gap is about two to one.
  • the dimensions of the spark gap that is, the spark distance or distance between electrodes, and the pressure of the gas therebetween are critical parameters.
  • the relation is so definite that the sphere gap is often used as a rough measure of high voltages.
  • a two centimeter spark in air at normal pressure corresponds to a potential difference of 56,300 volts; a five centimeter gap to 102,250 volts.
  • the distance between gaps, the shapes of the gaps and the pressure of the gas in the gaps are all critical in determining the switching voltage and the other operating parameters mentioned above.
  • the shape and spacing between electrodes are actually matters of very little moment (except for the maximum voltage the tube can hold-01f).
  • the pressure of the gas used in the gap can vary over wide ranges without adversely affecting the operation of the device.
  • the electrodes may be rough or smooth, they may be cylindrical or spherical, they may be skewedand irregular, and essentially the same operating results are satisfactorily obtained.
  • the tremendous operating voltage range of the switch in accordance with the invention as indicated in paragraph 3A permits the utilization of voltage supply sources that may ordinarily be subject to considerable variation with ambient conditions. For example, wide temperature variations may result in wide voltage ratings for a battery that may be part of the circuit. Nevertheless, switching can be performed in accordance with the instant invention because of the tremendous dynamic voltage range of the switch (50 volts being the practical lower limit encountered). Concom-itantly, the need for voltage regulators in the circuit is eliminated, since the switch will operate regardless of the level of the applied voltage. Considerable circuit savings are thereby poss-ible.
  • one of the electrodes may 'be shaped as the external envelope of the tube, and because it is metal, may provide electrical shielding for the whole device.
  • one of the electrodes may itself serve the function of an electrical shield.
  • the primary source of charged particles is derived from a reversible electrical breakdown of the insulator bet-ween two closely spaced trigger electrodes.
  • the insulator effectively breaks down across its surface and generates a cloud of ions and electrons.
  • This cloud of charged particles serves as the main source of charged particles for forming the conductive path between the two main electrodes.
  • Secondary emision from the switch electrodes and ionization of the little gas that may exist within the gap also contribute.
  • the gap between the main electrodes will break down if a suffrciently high potential is applied therebetw-een.
  • the relationship for the minimum voltage that will cause a breakdown is known as Paschens Law and is Well known to those skilled in the art. Expressly, it indicates that this hold-off potential is directly proportional to the product of pressure and distance between main electrodes (for any particular gas).
  • Paschens Law the relationship for the minimum voltage that will cause a breakdown is known as Paschens Law and is Well known to those skilled in the art. Expressly, it indicates that this hold-off potential is directly proportional to the product of pressure and distance between main electrodes (for any particular gas).
  • Paschens Law it is, of course, necessary to make sure that the requirements of Paschens Law are satisfied so that the gap does not break down at some voltage below the maximum switching voltage of interest. This, however, is a condition easily met within the confines of the requirement that the mean free path of the charged particles "be greater than the distance between the main electrodes.
  • Paschens Law may be represented by a curve which has as its ordinate the holdoff voltage, and as its abscissa the product of pressure and distance betweenelectrodes. As will be described in greater detail below, this curve is concave upwards and has one minimum point in it.
  • the physical structure of the well-known triggered spark gap is described by a point on the curve to the right of this minimum, and in all cases pressures of one-half to one atmosphere are in this range to the right.
  • the physical structure of the instant invention is described by a point to the left (the low pressure side) of the minimum of Paschens curve, which also satisfies the requirement that the mean free path of the charged particles be substantially greater than the gap distance.
  • the switch in accordance with the invention can be substituted for every application wherein a triggered spark gap is used, as well as in many others.
  • a triggered spark gap is used, as well as in many others.
  • the switch of the instant invention may well be substituted, and in certain applications the mere decrease in physical size of the instant switch over that of the thyratron and ignitron would indicate its use if for no other purpose than that.
  • FIGURE 1 is a cut-away perspective view of a switch in accordance with the invention.
  • FIGURE 2 is a cross-sectional view of the trigger electrodes of the switch of FIGURE 1;
  • FIGURE 3 is a graphical representation of Paschens Law, well known in the art, and useful in explaining an important physical parameter of the invention
  • FIGURES 4, 5 and 6 are views of another switch in t5 accordance with the invention having a different geometry from that of FIGURES 1 and 2;
  • FIGURES 7 through 10 are graphical representations of the variations in certain performance criteria of a prior art switch.
  • FIGURE 11 is a graphical representation for the switch of the instant invention, of the same performance criteria as represented in FIGURES 7 through 10.
  • FIGURE 1 there is shown a cut-away view of an illustrative embodiment, given by Way of example, of a switch in accordance with the invention, with external leads connected to a schematically represented external triggering and load circuit, which is typical of the applications for high current switches.
  • the switch comprises as its basic elements a positive and negative electrode, trigger electrodes and the gas pressure within the vacuum-tight tube.
  • the negative electrode of the tube of FIGURE 1 is a metallic cylindrical envelope 11 forming the major external portion of the tube. Cylinder 11 has a bottom face 17 and a top face '18 as well as its cylindrical walls. Because of the high current supported by the switch, negative electrode 11 is preferably made of a metal having a high melting point such as tantalum or molybdenum.
  • the positive electrode is in the form of an annular metal ring 12 disposed with the plane of the ring parallel to the bottom face of envelope 11.
  • a rod 13, secured at one point on the ring, extends out through an aperture in the cylindrical wall of electrode 11.
  • Rod 13 is supported in an insulator 14 and is thence connected to an external load circuit 15.
  • the positive electrode is in this way physically secured and fixed within negative electrode 11, and is spaced and electrically insulated therefrom.
  • Insulator 14 is supported in turn, relative to the aperture in envelope 11, by a bushing 16.
  • the insulator 14 is preferably a ceramic material capable of withstanding high temperatures.
  • a particularly desirable ceramic of this type comprises ninety-five percent Al O with the remaining five percent comprising Cr O SiO MgO and Ca().
  • a commercially available ceramic having this composition goes under the trade name of Diamonite, P3142-1.
  • Positive electrode 13 must also be of a metal which can withstand high temperatures, and similarly may be of molybdenum or tantalum, although Kovar also has been found excellent for this purpose.
  • Top face 18 of envelope 1 has a centrally disposed aperture therein which, as will be seen serves to permit the penetration therethrough of the lead from one of the trigger electrodes.
  • Astride the top of face 18 is a ceramic cap 19 which serves to completely close the envelope otherwise formed by negative electrode 11. Ceramic cap 19 may similarly be of the ceramic material 1 described above.
  • the trigger electrodes comprising rod 20 are disposed along the longitudinal axis of cylindrical electrode 11.
  • the details of the negative electrodes and rod 20 are presented more clearly in the detailed cross-sectional viewof FIGURE 2.
  • Rod 20 comprises three concentric or coaxial layers.
  • Ceramic rod 21 forms the core upon which the other layers are formed. This rod, too, is preferably of the ceramic mentioned above.
  • a layer 22 is formed about ceramic rod 21 by metallizing the external layer with a combination of molybdenum and manganese.
  • External to layer 22 is a metallic layer 23 which is preferably of titanium or molybdenum, and which may be vacuum-deposited upon the outer surface of metallized layer 22.
  • a circumferential groove 24 is cut around rod 20, so as to penetrate solely the external metal layer 23. The disposition of circumferential groove 24 is con centric with positive electrode 12. Groove 24, then, effectively divides rod 20 into two separate trigger electrodes, 25 and 26.
  • rod With the device operating as a kilovolt switch, rod may be .06 of an inch in diameter, with the metallized layer 22 less than .001 of an inch thick, and the circumferential groove having a width (which serves to space electrodes and 26 from each other) of .001 to .008 of an inch.
  • Th trigger electrodes of which rod 20 is comprised are mounted within negative electrode 11 in the vertical position mentioned above.
  • the lower part of trigger electrode 26 is secured in a grommet-like fixture 27, which is in turn secured to the bottom face 17 of electrode 11.
  • a similar grommet-like fixture 28 is secured to the top portion of trigger electrode 25. It may be seen from this that trigger electrode 26 is at the same electrical potential as is the negative electrode 11. Coupled to trigger electrode 25 is electrical lead 29,.which exits the tube through the aperture in face 18, and through a centrally disposed aperture in ceramic cap insulator 19. A triggering potential may be applied between electrodes 25 and 26 by virtue of trigger pulse source 9, which through step-up pulse transformer 10 is coupled to conductor 29 relative to trigger electrode 25, and to the grounded negative electrode 11 in electrical contact with trigger electrode 26.
  • the vacuum-tight structure of the switch is evacuated of gas to a very low pressure. It is preferable that an inert gas be in the tube at whatever pressure is used so as to avoid chemical reaction between the gas and the metal electrodes at the high temperatures characteristic of switch operation.
  • Typical and appropriate inert gasses are helium, nitrogen, krypton and xenon. However, hydrogen and air have each been used with relatively satisfactory results.
  • the pressure of the gas is preferably in the micron region, e.g., 100 microns of nitrogen, 500 microns of helium, 8 microns of air. The pressure selected is .a function of the particular gas, and the hold-off potential required for any given tube, as will be understood from the discussion relative to FIGURE 3 to be presented below.
  • FIGURE 3 Disclosed in FIGURE 3 is a typical representation of the Paschen curve mentioned above.
  • the ordinate represents the hold-off potential in volts, while the abscissa is the product of gas pressure and the shortest distance between the main electrodes of the gap.
  • Curve 31 is a typical Paschen curve, and is the curve characteristic of helium. It may be noted that this curve, which is concave upward, approaches the ordinate asymptotically; moving to the right along the abscissa, the hold-off voltage decreases to a minimum point and then once again increases to the right.
  • the curves of different gasses are disposed differently, but the basic outline remains the same.
  • curve 32 is the Paschen curve for nitrogen. Curve 32 approaches the ordinate asymptotically more rapidly than does curve 31, and the minimum point is displaced from that of helium curve 31. However, the curves are qualitatively the same.
  • horizontal line 33 passes through the curve at two points and intersects the ordinate at a particular hold-off potential.
  • line 33 at the ten kilovolt hoid-oft level.
  • the pressure at point 35 is appropriate for the prior art triggered spark gap and is ordinarily in the range between one-half and one atmosphere of helium (the exact figure depending upon the electrode spacing). This provides a sufficient density of particles such that the gas may be readily ionized to form the conduction path.
  • the gas is sufficiently dense such that the mean free path of any particle in a triggered spark gap is substantially less than the actual distance between the main electrodes.
  • the pressure may well be in the order of 500 microns.
  • the difference of potential applied across the groove 24 between the trigger electrodes 25 and 26 results in an electrical breakdown across the surface of the metallized ceramic layer 22 located within the groove 24. This results in the generation of a cloud of ions and electrons which are responsible primarily for forming the conduction path between positive electrode 12 and negative electrode 11.
  • the high voltage switch changes from an essentially non-conducting state to a state of high conduction with the application of the trigger pulse.
  • Energy which is stored in capacitor 38 (in shunt with the positive and negative electrodes of the switch) flows through load 15 and through the high current switch itself.
  • Resistor 39 in series with load 15 and the positive and negative electrodes of the switch, serves as a charging path for capacitor 38, and as isolation between the external circuit shown and the charging supply during the discharge period.
  • the high voltage applied between the terminal of resistor 39 and the negative electrode 11 of the switch may typically be 10,000 volts, although applications have been successfully utilized in accordance with the invention to 30,000 volts, and there is no reason now known why larger potentials may not be readily switched in accordance with the invention. With the tubes designed to operate at these potentials, satisfactory switching has been achieved with applied potentials of as low as 50 volts without any demonstrable change in the performance of the tube, even though an oscilloscope with a .1 micro- 9 second per centimeter sweep was used to analyze performance.
  • the trigger electrodes 25-26 were described as spaced from each other by groove 24 with the surface of metallized ceramic layer 22 therebetween. It should be understood that it is not necessary (but it is desirable) to metallize the ceramic prior to use of the switch. With the trigger electrodes spaced by the ceramic Without metallization, the device operates satisfactorily provided that a somewhat higher potential triggering pulse be applied between the trigger electrodes. This causes switching in the manner described above. In this process, a certain amount of metallic sputtering from the electrodes develops, and metallization of the ceramic occurs in the insulated area between trigger electrodes as a result of the ordinary use of the tube. After sputtering performs the metallizing function, the trigger pulse required to fire the tube is once again at the level appropriate for the metallized ceramic.
  • a single trigger pulse may be applied simultaneously to a multiplicity of switches, each one of which may control a separate and independent external circuit, including its own separate and independent load. Simultaneous switching occurs in this way irrespective of possible different impedances in the different external circuits and irrespective of different potentials that may be applied in each of the multiplicity of circuits. Furthermore, because of the dynamic operating range of the tubes, the same type tubes may be used for all of the different circuits irrespective of what applied voltage is used for each one of the circuits.
  • FIGURE 4 there is disclosed an alternative form of a switch inaccordance with the principles of the invention.
  • This switch, and that of FIG- URE 1, are, in most respects, similar, but the geometry of the positive electrode and the geometry of the triggering electrodes are substantially different in FIGURE 4.
  • the negative electrode 41 of FIGURE 4 is a hollow cylindrical shell similar in shape to the negative electrode of FIGURE 1.
  • the postive electrode 42 is hemispherical in shape, unlike the ring electrode 12 of FIGURE 1, but is mounted within cylinder 41 in approximately the same position.
  • An external lead 43 is secured to positive electrode 42, and passes upwardly out through the tube to be coupled to the external circuit which is not shown.
  • the external circuit may be the same as that shown in FIGURE 1; thus, lead 43 may be connected to the load circuit, such as load 15 of FIGURE 1.
  • a cylindrical insulator 64 preferably of the ceramic discussed above, serves to close the top of the tube through which lead 43 from the positive electrode passes out of the tube. In this way, the insulator 64 serves to space and electrically insulate the negative electrode portion at the top of cylinder 41 from positive electrode lead 43. This ceramic material may be brazed to the cylindrical negative electrode as discussed above relative to FIGURE 1.
  • the trigger electrodes of FIGURE 4 have a substantially different geometry from that of FIGURE 1.
  • the trigger electrode assembly comprises hollow cylinder 40, a portion of which is shown in cross-sectional view in FIGURE 6, and the top view of which is shown in the cross-sectional view of FIGURE 5 taken along line 55 of FIGURE 4.
  • the top surface of cylinder 40 conforms to a conical shape, with the hollow bore portion of the cylinder at the center thereof.
  • the outer surface of the cylindrical walls and the inner surfaces forming the bore of cylinder 40 are covered, as by vacuum deposition, with an appropriate metal such as titanium or molybdenum.
  • metal deposit 44 on the external surfaces of the cylinder also occupies a portion of the conical surface at the top of the cylinder.
  • Metal layer 44 in two extended sections, 47 and 48 occupies part of the surface of the conical section right up to, but just short of, the apex ridge of the conical section. This external metal layer 44 is one of the two trigger electrodes.
  • the other of the two trigger electrodes is metal layer 50 disposed on the inside bore surface of the cylinder 40.
  • Metal layer 50 which coats the bore hole' wall of cylinder 40 extends the length of the bore right up to, but just short of, the apex ridge of the conical top surface of the cylinder.
  • trigger electrodes 44 and 50 are spaced from each other a minute distance fixed by the chamfered edge 51 of the apex ridge of the conical sec tion at the top of cylinder 40.
  • the distance between electrodes 44 and 50 across chamfered edge 51 may typically be between .001 and .008 of an inch, as was the width of circumferential groove 24 of FIGURE 1. This close spacing occurs, however, only along sections 4'7 and 43 of electrode 44.
  • Trigger electrode 54 is in physical contact with external lead 49, which in turn may be coupled to the external circuit, and in particular to a source of triggered pulses. Electrode 44 is in physical contact with a cap 52, in turn physically secured to the bottom face of negative electrode cylinder 41, which in turn may be grounded, as was the case in the embodiment of FIG- URE 1. 1
  • a trigger electrode in each of the embodiments of FIGURES 1 and 4 is shown to be physically connected to the main negative electrode, such physical contact is not necessary. All that is required is that one trigger electrode be at approximately the same reference potential as is the negative main electrode.
  • An electrical lead 53 is coupled to the negative main electrode 41. The triggering pulse may therefore be applied across the terminals 49 and 53 in order to apply the potential across trigger electrodes 50 and 44.
  • the precise structure of the trigger electrodes may be seen from the view of FIGURE 6.
  • Metal layer 50 forming one of the trigger electrodes, is shown in cross-section on the inside surface of the cylinder bore hole, while the metal layer 44 which is the other trigger electrode is on the outside surface of the cylinder and its top conical portion.
  • Metallized ceramic layer 57 is interposed between trigger electrode layers 44 and 50 on the one hand, and the inner ceramic insulator 58 upon which the metallized layer 57 and the trigger electrodes are disposed.
  • the gas within the body of the tube is as was described with reference to FIGURE 1 and satisfies the require ments of the description relative to FIGURE 3.
  • the main conduction path is between the top of cap portion 52 secured to and part of the negative electrode 41, and the inside face of hemispheric positive electrode 42.
  • This geometry is particularly advantageous in that metallization that develops from sputtering because of conduction between the electrodes is precluded from forming on the lower surface of the ceramic insulator 64. In this way, electrical isolation between negative electrode cylinder 41 and lead 43 to positive electrode 42 is maintained.
  • FIGURES 1 and 4 are, of course, merely examples. Literally dozens of other geometries may be utilized readily within the purview of the invention and in accordance with its principles. Certain geometries may have different ancillary advantages, as is the case with the geometry of the electrodes of FIGURE 4, wherein an undesirable effect of sputtering is substantially eliminated. The principle, however, remains the same. Thus, in the embodiment of FIGURE 4, it is the breakdown of the layer along the region 51 in between the metal trigger electrodes 44 and 50 which 1 1 provides the cloud of electrons and ions required for the conduction path, just as it was the rnetallized ceramic in the narrow groove 24 between trigger electrode segments 25 and 26 in FIGURE 1.
  • FIGURES 7 through 10 The curves of FIGURES 7 through 10 are presented to show the delay and jitter characteristic of a good and typical prior art triggered spark gap tube, for comparison with these parameters in the tube in accordance with the invention.
  • the broken line curve is the trigger pulse and the solid line curves show condition across the main electrodes in time relation to the "pulse. Each interval on the axis represents 0.1 of a microsecond.
  • FIGURES 7 and 9 show the switching of a triggered spark gap with 2,200 volts applied between the main electrodes.
  • FIGURE 7 shows several firings or shots taken after the first S firings
  • FIGURE 9 shows several shots taken after the first 150 shots.
  • the delay is greater after 150 shots than after 50 shots. This increase in delay with the number of firings is characteristic of triggered spark gap operation.
  • FIGURES 8 and 10 show these characteristics with 1,800 volts applied between main electrodes. At this lower potential, the delay is clearly longer than at 2,200 volts. Furthermore, the delay for FIGURE 10, after 150 shots is longer than for FIGURE 8 after 50 shots.
  • FIGURE 11 presents curves for the switch in accordance with the invention. This is what the oscilloscope showed both at 2,200 volts and at 1,800 volts switching potential, and after 50 and 150 shots at each voltage. It may be noted that there is literally no delay in FIGURE 11 (within the measuring capacity of the equipment) and there is no jitter. This performance is characteristic of the switch of the inventions While we have shown particular embodiments of our invention, it will be understood that many modifications may be made without departing from the spirit thereof, and we contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.
  • a switch comprising: positive and negative main electrodes with a given inter-electrode distance therebetween, said electrodes being disposed within a vacuumtight container; the gas pressure within said container being sufficiently low such that the mean free path of gas particles within said container is greater than said inter-electrode distance; and means for generating electrons and ions in said container independently of said main electrodes and independently of any gas within said container to provide a conductive path between said positive and negative main electrodes.
  • a switch comprising: positive and negative main electrodes with a given inter-electrode distance therebetween, said electrodes being disposed within a vacuumtight container; the gas pressure within said container being sufficiently low such that the mean free path of gas particles within said container is greater than said interelectrode distance; and means for generating electrons and ions in said container independently of any gas within said container to provide a conductive path between said positive and negative main electrodes, said means for generating electrons and ions comprising first and second electrodes spaced a short distance from each other by an insulator and disposed adjacent said electrodes; and means for applying a difference of potential between said first and second electrodes.
  • a switch comprising: electrodes having an interelectrode distance between the positive and negative main electrodes, said electrodes being disposed within a vacuumtight container; means for generating electrons and ions in said container independently of said main electrodes and independently of any gas within said container to provide a conductive path between said positive and negative main electrodes; the gas within the container having a pressure which when multiplied by said interelectrode distance defines a point on the low pressure side of the Paschen curve for said gas.
  • a switch comprising: electrodes having an interelectrode distance between the positive and negative main electrodes, said electrodes being disposed within a vacuumtight container; means for generating electrons and ions in said container independently of any gas within said container to provide a conductive path between said positive and negative main electrodes; said means for generating electrons comprising first and second trigger electrodes spaced from each other by an insulator and disposed adjacent said positive and negative electrodes; said spacing between trigger electrodes being smaller than said inter-electrode distance; and means for applying a difference of potential between said trigger electrodes; the gas within said container having a pressure which when multiplied by said inter-electrode distance defines a point on the low pressure side of the Paschen curve for said gas.
  • a switch comprising: positive and negative main electrodes with a given inter-electrode distance therebetween, said electrodes being disposed within a vacuumtight container; the gas pressure within said container being sufficiently low such that the mean free path of gas particles within said container is greater than said interelectrode distance; and means for generating electrons and ions in said container independently of said main electrodes and to provide a conductive path between said positive and negative main electrodes, said electron and ion generating means being independent of the gas within said container.
  • a switch comprising: positive and negative main electrodes with a given inter-electrode distance therebetween, said electrodes being disposed within a vacuumtight container; the gas pressure within said container being sufficiently low such that the mean free path of gas particles within said container is greater than said inter-electrode distance; and means for generating electrons and ions in said container to provide a conductive path between said positive and negative main electrodes,
  • said electron and ion generating means being indethat the mean free path of gas particles within said container is greater than said inter-electrode distance; means for generating electrons and ions in said container to provide a conductive path between said positive and negative main electrodes, said means for generating electrons and ions comprising first and second electrodes spaced a short distance from each other by an insulator and adjacent said main electrodes; a metallized surface on said insulator; and means for applying a difference of potential between said first and second electrodes.

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Application Number Priority Date Filing Date Title
US126364A US3248603A (en) 1961-05-10 1961-05-10 Mean free path gaseous discharge tube and circuit thereof
DEG34933A DE1238540B (de) 1961-05-10 1962-05-09 Elektrischer Schalter
GB17858/62A GB1012728A (en) 1961-05-10 1962-05-09 Triggered staple gap switch

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US126364A US3248603A (en) 1961-05-10 1961-05-10 Mean free path gaseous discharge tube and circuit thereof

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US3304465A (en) * 1962-06-25 1967-02-14 Hans W Hendel Ignition of electric arc discharge devices
US3317787A (en) * 1964-03-16 1967-05-02 Creveling Robert Electronic switch with means to halt the flow of electrons to initiate an arc discharge
US3696264A (en) * 1970-06-24 1972-10-03 Cornell Aeronautical Labor Inc Magnetically modulated vacuum arc diode
US9939235B2 (en) 2013-10-09 2018-04-10 Battelle Energy Alliance, Llc Initiation devices, initiation systems including initiation devices and related methods

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ZA753564B (en) * 1975-06-03 1977-01-26 South African Inventions A high voltage electric switch

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US2535886A (en) * 1949-07-26 1950-12-26 William R Baker Electronic switch
US2817036A (en) * 1956-04-26 1957-12-17 Richard B Neal Spark gap switch
US2909695A (en) * 1958-10-17 1959-10-20 Leonard J Melhart Coaxial magnetohydrodynamics switch device
US2935648A (en) * 1959-01-05 1960-05-03 Gen Precision Inc Bridge wire triggered spark gap
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US1948720A (en) * 1929-02-05 1934-02-27 Westinghouse Electric & Mfg Co Television receiving lamp
US1871279A (en) * 1930-01-09 1932-08-09 Westinghouse Lamp Co Glow relay tube
US2409716A (en) * 1941-09-27 1946-10-22 Westinghouse Electric Corp High-voltage discharge device
US2340799A (en) * 1942-10-19 1944-02-01 Bell Telephone Labor Inc Electronic discharge device
US2535886A (en) * 1949-07-26 1950-12-26 William R Baker Electronic switch
US2817036A (en) * 1956-04-26 1957-12-17 Richard B Neal Spark gap switch
US2987641A (en) * 1957-01-31 1961-06-06 Trub Tauber & Co A G Irradiation system for an electron beam apparatus with cold cathode
US2909695A (en) * 1958-10-17 1959-10-20 Leonard J Melhart Coaxial magnetohydrodynamics switch device
US2935648A (en) * 1959-01-05 1960-05-03 Gen Precision Inc Bridge wire triggered spark gap
US3087092A (en) * 1961-05-10 1963-04-23 Gen Electric Gas generating switching tube

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3304465A (en) * 1962-06-25 1967-02-14 Hans W Hendel Ignition of electric arc discharge devices
US3317787A (en) * 1964-03-16 1967-05-02 Creveling Robert Electronic switch with means to halt the flow of electrons to initiate an arc discharge
US3696264A (en) * 1970-06-24 1972-10-03 Cornell Aeronautical Labor Inc Magnetically modulated vacuum arc diode
US9939235B2 (en) 2013-10-09 2018-04-10 Battelle Energy Alliance, Llc Initiation devices, initiation systems including initiation devices and related methods

Also Published As

Publication number Publication date
GB1012728A (en) 1965-12-08
DE1238540B (de) 1967-04-13

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