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Feb. 24, 1959 MR. CLELAND > _ 2,875,394

VOLTAGE MULTIPLICATION APPARATUS 7

Filed Oct. 29, 1956 5 Sheets-Sheet l

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Marshall R. Cleland, Rock Hill, Mo., assignor, by mesne assignments, to Radiation Dynamics, Inc., New York, N. Y., a corporation of New York

‘ Application October 29, 1956, Serial No. 618,862

22 Claims. (Cl. 321-15)

This invention relates to voltage multiplication appara ms, and more particularly to voltage multiplication ap par'atus which provides a substantially constant high voltage D. C. output potential. Among the several objects of the invention may be

noted the provision of voltage multiplication apparatus which operates from an A. C. ‘supply and supplies a substantially constant D. C. output potential of the order'of one million or more volts at improved D. C. output current levels; the provision of such apparatus which has a high e?iciency of voltage multiplication; the provision of apparatus of the class describedvwhich may conveniently incorporate an accelerator tube for the production of high energy ion or electron beams; the provision of such apparatus in which the conven tional type of ?lter condenser is eliminated; and the provision of voltage multiplication apparatus which is compact in size and economical in cost. Other objects and features will be in part apparent and in part pointed out hereinafter.

Within the past few years there has been a growing need for a compact, e?icient and economical source of high-voltage D. C. which would provide potentialsvin the order of a million or more volts. and with such power capabilities that current in the order of l to 10 milli amperes could be supplied. One of the most promising approaches toproviding a source of such high poten tial and current capabilities has been the use of cascaded recti?ers. By interconnecting these recti?ers in a circuit which supplies each such recti?er from a single source of relatively low A. C. potential and effectively connects the D. C. output voltages thereof in series, a recti?er high-voltage D. C. output potential is provided that is many timesithe amplitude of the input A. C. potential. The trend has been toward operation at higher frequen cies in order to reducethe size and cost of the apparatus. However, the requirements of condensers capable of handling the D. C. potentials and high frequency A. C. current values, and the loss of efficiency relative to the theoretical voltage gain as the number of recti?ers is

' increased, have sharply restricted the commercial prac ticality of such apparatus.

’ In accordance with the present invention, voltage multi plication apparatus is provided which overcomes these difficulties and has additional signi?cant advantages. In a broad sense my apparatus comprises a pair of metallic electrodes across which is applied an A. C. potential, a number of series-connected recti?er units positioned be tween said electrodes, and a corona shield connected at each of the electrical junctions thereby formed between each of the recti?er units. A. C. potentials of substan tially‘ equal amplitude are capacitively coupled across successivepairs of corona shields by means of the ca— pacitance existing between each of these corona shields and the electrodes. - '

Theinvention ‘accordingly. comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims. ‘

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1 2,875,394 Patented Feb. 24, 1959v ice 2

In the accompanying drawings, in which several of - various possible embodiments of the invention are illus trated, Y . ' '

Figs. 1 and 2 are side and front end elevations, re spectively, of a voltage multiplication apparatus of the present invention, with various parts broken away and shown in section; .

Fig. 3 is an enlarged cross section taken on line 3 of Fig. 1; '

Fig. 4 is a longitudinal cross section‘ taken on‘ linev 4—4ofFig.1; -‘ _‘ ‘

Fig. 5 is a view of an accelerator tube component of the apparatus of the present invention; i '

Fig. 6 is a schematic representation of .the electric cir~. cuitry of the apparatus of- Figs. 1-4; . . . -

Fig. 7 is a view similar to Fig- '1, showing an alternate. embodiment of the present invention; - . '- ‘ . 1

Fig. 8 is a schematic’ representation of the electric‘ circuitry of the apparatus of Fig. 7; and ., ‘ ‘ ;

. Fig. 9 is a schematic representation ‘.of' the. physical. layout and electric circuitry of still another embodiment of the present invention. ‘

Corresponding reference characters indicate corree spond'ing . parts throughout the several views of ‘the drawings. ; ‘

Referring now more particularly to Figs. l-S, an elec trically grounded, heavy steel, cylindric, gas-tight pres sure container is indicated at reference numeral 1. This container includes a pair of end closures or covers 3 and 5 bolted to a body portion 7 of thecontainer. A pair of trunnions 9 is provided for mounting the con; tainer 1’ so as to permit movement about the axis of the ‘trunnio'ns. Enclosed within container 1 are a num ber of cascaded recti?er units (constituted by one or two diode vacuum recti?er tubes V1 to V36), a pair of

' opposed metallic electrodes or shells E1 and E2, an

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accelerator tube AT, inductor I, and various ‘associated components. ‘ '

' The electrodes E1 and E2 are mechanically mounted within container 1 by means of insulated mounting brackets B1, B2 and B3 which space the exterior sur faces of these electrodes away from the interior of con; tainer 1 and each other. The edges of each of these shells E1 and E2 are ‘rounded and smooth as indicated at EEl and EEZ. A generally 'C-shaped smooth length of metal tubing TG is mounted on brackets B1, B2 and B3 between the electrode edges BB1. and -EE2. 'As tubing TG is directly connected to the closure 3 by the conducting portion of bracket B3, it is at groundpoten tial; Thus, they electrodes aEl and E2 are insulated from each other and container 1, while tubing‘TG is grounded. _ - ‘ p -

Closure p-5v carries on its inner surface two supporting brackets B4 and B5 to which are a?ixed a pairofifcen trally disposed ,I-beams IE1 and IE2 made outiof‘plastic or some other suitable insulating materiaL' Positioned between the inner'?ange surfaces of 'each of thebeams and supported thereby are the vacuum recti?er tubes V1 to V36. They are located in two generally parallel ver tical banks and in a generally zig-zag con?guration.‘ The cathode of tube V1 is maintained at ground potential by interconnecting the cathode cap of tube V1 via a metal clip CL to the closure 5. Similar metal clips'CL me" chanically support the anode and cathode caps of allthe recti?ers V1 to V36. The clip- supporting the anode cap of V1 is electrically connected by a cross boltv'CB to the clip supporting the cathode cap of V2. ' In alike manner, the anode and cathode caps of V3'an'd V4, re’ spectively, are mechanically supported and‘ electrically interconnected. . ‘ . ‘ 1 _. - T:

In order vto complete a series-connected anode-to cathode. circuit between the cascadedrecti?ers‘ Vlto

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V36, a number of arcuate sections of metal tubing CS40 to C881 are provided. These sections are positioned par allel to each other about a central longitudinal axis of the container and serve to interconnect electrically in series pairs of end-to-end recti?er tubes which pairs then function as single recti?er units. This is accomplished by mechanically connecting each of the clips CL lo cated inside the ?anges of the I-beams B1 and 1132 by means of springs S, brackets B, and screws SC to the upper and lower inner surfaces of each of the nearest corona shields C845 to C877 (Fig. 3). The alternate corona shields C845 to C877 which remain unconnected may be left electrically ?oating or may be interconnected laterally by a cross bolt to the opposite corona shield which is actually serving as an electrical path between a recti?er anode and the cathode of the next recti?er tube on the other side of the web of the I-beams. Arcuate connector tubing sections CS40 to C843 are grounded (i. e., connected to closure 5), and the remaining sections C878 to C881 are commonly connected to a high-voltage terminal as indicated at reference character HVD. This terminal is constituted by a metallic spinning of dome shape. Dome HVD and the connector sections CS40 to

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C881‘ are physically supported by triangularly shaped A plastic beams TBl and TB2, which extend longitudinally of the container. Two additional plastic supports TB3 and T B4 of similar

triangular shape are positioned respectively above and below the outside horizontal sections of beams B1 and IE2 and spaced therefrom by insulating ribs R131 to RB4. Within the two long rectangular box-like spaces thus formed between these ribs RBI, RBZ and RB3, R134, re spectively, a number of tubular condenser elements CD are located (Figs. 3 and 4). Each of these condenser ele ments is made of a ceramic cylinder plated on the oppo site end surfaces with a conducting metallic ?lm. These condenser elements are organized in a series-parallel ar rang‘ement by stacking a number of them in rows and columns between metal plates MP, to constitute a num ber of condensers CCA, CCB and CC1 to CC16. These metal plates are respectively connected to each of the adjacent anode-cathode recti?er junctions by means of conducting connectors CN, except for the terminal metal plates MP of CCA and CCB which are connected, as will be described subsequently, to the inductor 1.

Another series of arcuate tubular corona shields CS1 to C839 are physically mounted by means of bolts ET on supports TB3 and TB4. Pairs of adjacent shields CS1 to C836 are commonly connected to each respective anode-cathode recti?er junction. That is, shields C81 and CS2 are connected to the junctions between the anode cap of V1 and the cathode cap of V2, while corona shields CS3 and C84 are connected to the anode-cath ode junction between tubes V3 and V4. Shields C833, C834, C837 and C838 are commonly connected to a dome-shaped metallic spinningDl while shields C835, C336 and C839 are similarly interconnected to an iden tical spinning D2. _ I The anode cap of the last recti?er V36 is intercon

nected to the high-voltage dome or terminal HVD and to an end housing EH of the accelerator tube AT (Fig. 5). This accelerator tube is made up of a series of hollow tubular cylindrical sections GS of glass or plastic, stacked end-to-end and separated by metallic rings MR. Accel~ erator tube AT is positioned on the central longitudinal axis of container 1 in an elongate rectangular box-shaped space between the opposing surfaces of the inner ?anges of beamstlBl and IE2, and two plastic spacing ribs RBS and RB6.‘ , Accelerator tube AT terminates at a ?exible metal bellows BL which in, turn is joined to an'accelerator tube extensionv XT. This extension XT extends centrally through the container closure 5 and a conventional gas -tight sealing unit 8U so as to project through a T con nector TC. ' A hose HS from a vacuum pump is vcon

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nected to one of the T outlets and another carries a probe PB. The end housing EH includes a conventional electron source, such as a hot cathode, and the usual as sociated grids and focusing elements. As these are well known to those skilled in the art, no detailed drawing or description is included herein. For the same reason and to avoid obscuring any of the essential elements of the present invention, insulated control rods, which serve to adjust the cathode temperature and the relative poten tials on the grid and focusing elements, and a compact remotely driven generator for powering the cathode of the electron source are not shown. A series of resistors R are connected between adjacent rings MR to assure a substantially lineal potential gradient between the right, or high-voltage, end of the accelerator tube AT and the left, or ground potential, end thereof. A radio frequency generator, which supplies A. C.

power, preferably of a frequency range in .the order of 2G to 200 kc., is interconnected to the apparatus by co axial cables CXI and CX2. Any customary coupling method of transferring R.:F. power from the R.-F. gen erator to inductor I may be employed. The inductor which, for the purposes of the voltage multiplication ap paratus of the present invention, serves as the source of A. C. power, has a pair of terminals connected by leads I1 and I2 to electrodes E1 and E2, respectively. In— ductor I also has a center tap which is connected via wire CT and a milliammeter MA to ground. A pair of inter mediate taps of inductor I are electrically connected as indicated at I3 and I4 to the end plates MP of con densers CCA and CCB. The voltage multiplication apparatus as illustrated in

Figs. 1-5, accordingly, is vbroadly constituted by an A. C. power source I, supplied with electrical energy from an R.-F. generator and connected to apply an A. C. potential across metallic electrodes E1 and B2. A number of cascaded recti?ers V1 to V36 are series-connected anode to-cathode between an A. C. neutral or ground (as con stituted by the center tap of inductor I) and a high— voltage terminal HVD. This terminal is electrically con nected to the cathode of an electron source contained within housing EH of accelerator tube AT. This tube is connected between ground and the high-voltage ter minal to provide an evacuated lineal path for the elec trons emitted from the cathode and accelerated in their course down the tube AT. . The vacuum recti?ers V1 to V36 are organized in a

series of recti?er units. One type of unit is made up of single recti?er tubes, i. e., V1 and V36, while the remain ing tubes V2 to V35 are paired so that each pair (e. g., V2, V3 and V4, V5, etc.) constitutes a recti?er unit.

It will be noted that the entire D. .C. apparatus (recti ?ers, corona shields, condensers and accelerator tube) is mounted on the interior of closure 5 by means of brackets B4 and B5 and that convenient access to the various com ponents of this apparatus can be accomplished merely by unbolting closure 5 and moving it to the left. Asthe spacing and relative placement between the corona shields CS1 to C831, the edges EEI and EEZ, and the interior surface of E1 and E2 are such that clearance is provided, the end closure and the above-noted associated com ponents may be conveniently removed from the normal position wherein these components are nested between the electrodes E1 and B2.

In order to increase the limits of relative potentials, both I). C. and A. C., which may be impressed across various elements of this voltage multiplication apparatus Without sparking or corona discharge, it is preferred that container 1 be ?lled with some atmosphere other than air, such as sulfurhexa?uoride gas at above-atmospheric pressure. ' > . .

Referring now more particularly to Fig. 6, the elec trical circuitry equivalent to the physical structure de scribed above in Figs. 1-4 is schematically illustrated. It will be seen that the A. C. potential which is impressed

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between electrodes E1 and E2," and which is preferably in the order of 50,000 to 150,000 v. at a frequency of the range of 20 to 200 kc., is supplied by inductor I. A somewhat reduced A. C. potential is applied to con~ densers CCA and CCB. Thus an A. C. potential exists across each of the recti?er units V2, V3 to V34, V35, this potential being approximately halved on the initial and terminating recti?er units V1 and V36. The inter electrode (anode-cathode) capacities of each of the recti ?er tubes are indicated by dashed lines at CV1 to CV36. The stray capacitances which are formed between the various corona shields CS1 to C839 and the domes D1 and D2 are similarly indicated at CESl to CES19.

If the circuitry of Fig. 6 is now considered, eliminat ing the electrodes E1 and E2, it will be apparent that there are stray capacitances between the corona shields CS1 to C339 and the grounded container, rather than between these shields and the electrodes E1 and E2. As there is effectively a single A. C. input potential con nected in parallel via condensers CCA, CCB and CC1 to CC16 across each of the recti?er units and the recti ?ed D. C. outputs thereof are effectively connected in series, a D. C. voltage multiplication takes place, whereby the theoretical no-load output voltage would equal the applied A. C. potential connected across condensers CCA and CCB multiplied by the number of full stages of recti?cation (i. e., the seventeen recti?er units V2, V3 to V34, V35 and the two single recti?er tube units V1 and V36). In the present instance (that is, without consideration of the electrodes E1 and E2), if the applied A. C. potential across CCA and CCB were 60,000 v. peak, the theoretical D. C. output should be 18><60,000, or 1,080,000 v. However, this theoretical value is not obtained in practice, but instead a sharply decreased D. C. output voltage is obtained. This difference be tween the theoretical and actual D. C. output voltage is due to a combination of factors. The stray capacitances between the corona shields and ground (in the absence of electrodes E1 and E2) and the interelectrode capacities of the recti?er tubes cause A. C. currents to be drawn through the ?lter condensers CCA, CCB, CC1 to CC16. These currents produce ‘an A. C. ripple voltage across each ?lter condenser, which voltage is opposite in phase to the voltage across the inductor. Because of these A. C. displacement currents, the A. C. potential carried by the ?lter condensers to the recti?er units gets pro gressively smaller from left to right. These currents also cause dielectric heating in the ?lter condensers which complicates their design and is a distinct limiting factor in increasing the operating frequency of the apparatus, an increase in operating frequency being desirable in order to obtain high D. C. outputcurrent from the recti ?er circuit.

In accordance with the present invention, these dis advantages can be overcome by surrounding the cascaded recti?er units, condensers, corona shields, etc., by curved metal shells or electrodes, as shown at E1‘ and E2, which are electrically connected to opposite ends of the induc tor I. Then the stray capacitances CESl to CES19 ter minate at the electrodespEl and E2 as indicated in Fig. 6, rather than-at the grounded container 1. Assuming ?rst that the same A. C. potential is impressed across the electrodes E1 and E2 as is applied to condensers CCA and CCB (by moving connections I3 and I4 out ward to ‘the ends of the inductor), that component of the A. C. displacement current in the ?lter condensers CCA, CCB, CC1 to CC16 due to the stray capacitances between corona shields and the grounded container 1 is thereby eliminated, the A. C. ripple across these ?lter condensers is thereby reduced and the e?iciency of volt age multiplication is substantially increased.

If, however, as shown in Fig. 6, a higher A. C. po tential is impressed across E1 and E2 ascompared to‘ that coupled to the cascaded recti?ers through CCA, CCB,

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6 CC1l to CC16, the other component of .A. .C. displace-_ ment current in the ?lter condensers (i.' e., that due to recti?er interelectrode capacitances). can be completely cancelled by A. C. displacement currents ?owing through the capacitances between the corona shields and the elec trodes E1 and E2, which currents are now 180° out-of phase with the recti?er displacement currents. Thus, the entire undesirable elfect of all A. C. displacement cur rents in the ?lter condensers, which otherwise impose considerable limitations on the apparatus as noted, is eliminated. j The optimum value (Vp) of voltage to be applied be

tween electrodes E1 and E2 in order to achieve, this can cellation is expressed by:

where V is the peak A. C. voltage applied to the'?lter condensers, CV is the eifective interelectrode capacitance across one recti?er unit (two series~connected recti?er tubes) and CBS is the stray shield-electrode capacitance. The D. C. voltage‘ generated by- the apparatus will now be substantially‘ n><V (where n is the number of rectif ?er units,>i. e., eighteen in‘ the present illustration). ‘It is particularly desirable that‘these A. C.>currents are coupled directly and individually from the electrodes E1 and E2 to each of the recti?er junctions, because in that way each branch displacement current component through the separate recti?er units is compensated at its point of origin and there is no A. C. attenuation'due to A. C. current ?ow through the series-connected ?lter condensers CCA, CCB, CC1 to CC16. - As it is important to avoid any A.YC. ripple or rider

wave on the D. C. output potential, the high-voltage terminal HVD is made neutral as to A. C. In the illus trated apparatus this is accomplished because the A. C. potentials coupled to the domes D1 and D2 are equal in amplitude and opposite in phase, thus effectively plac ing HVD at an A. C. neutral. It will be understood that other methods of establishing an A. C. neutral at the high-voltage terminal, other than by using the above described balanced A. C. potentials of ‘domes D1 and D2, may be used. Examples of such otheroutput net~ works are shown in succeeding embodiments, but addi tional equivalent methods of establishing such A'. ‘C. neutrals (such as networks of inductances and condens ers, or off-center- inductor tapping,~etc.) could be ‘used and will be readily apparent to those skilled in they art. Similarly, input networks other than shown in‘ Fig. 6 and other embodiments disclosed herein are well-known to those skilled in the art and may be used as equivalentsl For this reason, such additional examples of such equiva lents are not speci?cally illustrated. ' i ' '

As described above, substantial or'complete compensa tion of the A. C. displacement currents in the ?lter condensers is accomplished by the apparatus of the present invention, which affords an opportunity for a still further improvement of voltage multiplication apparatus, viz., the complete elimination of'the conventional type of'?ltei' condensers CCA, CCB and CC1 to'CC16. Because of this complete A. C. current compensation, the capaci tances of the ?lter condensers can be reduced in inverse proportion as ‘the frequency of the A. C. power source is increased, while still maintaining an acceptably high D. C. output current capability and a high ef?ciency of voltage multiplication. If the operating frequency is su?iciently high, the stray capacitances CESl to CES19 will function additionally to ?lter the D. C. output volt age of the recti?er units. Then the'conventional ?lter capacitors may be removed.v Such apparatus isillus trated in Figs. 7 and 8. ._ ' . '

The voltage multiplication apparatus of Figstj7 and. 8 is identical to thatillustrated (Figs, .1-6) and described above. with the exception of certain modi?cations, as follows. The condensers CCA, CCB and CC1 to. CC16 are eliminated. An additional set of corona shields CSA

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and CSB are provided, which shields are movable along beams TB3 and T84 so as to provide variable capaci tances‘between each of these shields and the respective adjacent corona shields CSI and CS3, as indicated in dashed lines and at reference characters CEVI and CEV2. Two circular metal plates or elements C1 and C2 are adjustably mounted within domes D1 and D2 to pro vide independently variable capacitances between these plates and the interior surfaces of the domes as indicated at CEV3 and CEV4, respectively. Also, these plates C1 and C2 are interconnected by an electrical conduc tor EC via the primary of a transformer T (mounted within the accelerator tube end housing EH), the center tap of which is commonly connected to HVD and the anode of recti?er V36. Another modi?cation is the elimi nation of the intermediate taps on the inductor I. The operation of the Figs. 7 and 8 embodiment is like

wise similar to that of Figs. 1-6. The A. C. potential capacitively coupled individually to each of the recti ?er junctions (via stray capacitances CESl to CES16) provides. the same A. C. input potential across each of the recit?er units except the ?rst and last units which, in this example, have half the A. C. potential of the others. The ?ltering action of these stray shield-electrode capacitances and the recti?er tube interelectrode capaci tances is adequate to provide a substantially constant D. C. voltage of approximately the theoretical value at HVD and with adequate regulation even at the rela tively high beam current levels of 1 to 10 milliamperes, provided the frequency of the R.-F. generator is ' sut?ciently high. The stray capacitances CEVl and CEVZ are variable

to assure the proper A. C. amplitude across tubes V1 and V2, V3. The stray capacitances CEV3 and CEV4 perform an analogous function at the high-voltage (or right) end of the apparatus to assure the proper A. C. amplitude across tube V36 and V34, V35. These actions at the two ends are essentially the same in principle. By varying the dimensions of C1, C2 and/or the rela tive spacing to D1, D2, the A. C. potentials of D1 and D2 (and therefore of the recti?er junctions V33, V34 and V35, V36, respectively) and at HVD can be balanced and otherwise adjusted. Additionally, the current ?ow ing through conductor EC provides (via transformer T) heater power for the cathode of the electron source, thus eliminating the need for a separate-generator, as used in the preceding embodiment. A third embodiment of the present invention is illus

trated in Fig. 9, wherein .the recti?er units, instead of being physically arranged in a parallel zig-zag con?gura tion, are. positioned coaxially end-to-end. These recti ?er units are constituted by single recti?er tubes VEl to VE4.. It is ‘possible to extend this apparatus to any number of recti?er units. The cathode of the ?rst tube VEl is connected to ground through an R.-F. choke RFC. Another choke RFC interconnects the anode of VE4 to a high-voltage D. C. terminal HV. Each of the junctions between the recti?ers V131 and VE4, as well as the cathode and ‘anode caps of VEI and ‘IE4, respec tively, is surrounded by a hollow cylindrical corona shield CSC to CSG. A series of hollow cylindrical shells or electrodes ElA, E2A, ElB, B2B and BIG of an in creased diameter are coaxially mounted so as to surround CSC to. CSG, respectively. The alternate electrodes ElA, B1B and BIG are connected via I1 to one end of inductor I, while the remaining electrodes E2A and B2B are commonly connected by I2 to the other end of inductor I. The radial spacing between these elec trodes and shells can be ?lled with any suitable gaseous, liquid or solid dielectric material, thus enabling the vcapacities therebetween and the voltage insulation to be adjusted independently of the physical spacing. The ends of all the corona‘ shields and the electrodes are'to be rounded and smooth to prevent corona discharge or ‘sparking between elements. " ' '

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8 As the functions of the ?ve electrodes ElA to B2B

and the corona shields CSC to CSG are the same as those of electrodes E1 and E2 and shields CS1 to CS39, respectively, in the preceding embodiment, the opera tion of the voltage multiplication apparatus of Fig. 9 is similar. It is to be noted, however, that this embodi ment is capable of being constructed so as to have a mini mum outside diameter and thus have physical dimensions which permit the apparatus to be employed where nar row space limitations would otherwise restrict the use of the preceding embodiments. The power source for the cathodes of each of these

recti?er tubes of the present invention may be an inde pendent battery contained in the cathode housing, or a series of cascaded transformers (similarly located) in ductively linked to each other with suitable insulation precautions, or any other equivalent sources of energy known in the art. Such sources may be eliminated en tirely if semi-conductor (e. g., germanium or silicon di odes) or dry type (e. g., copper oxide or selenium) rec ti?er units are employed in place of the vacuum tube recti?ers illustrated herein. Also, if desired, gas-?lled recti?ers may be utilized. In the event recti?er units other than vacuum or gas~?lled recti?er tubes are used, it is to be understood that the terms “anode” and “cathode” as used herein identify the terminals of any such semi-conductor or dry type recti?er units. The inductor I is preferably of toroidal form in order

to minimize its external magnetic ?eld. This ?eld causes eddy currents within the steel walls of container 1 and its covers 3 and 5 which waste R.-F. power. The ex ternal magnetic ?eld of the coil may also impede the operation of the acceleration tube by de?ecting the elec— tron beam from its normally straight path. However, this coil con?guration may ‘be changed if the space re quirements permit, or structure modi?cations are made. Regardless of the con?guration of the inductor, it is of such inductance that it will resonate in an LC circuit (the capacitance of which is constituted by the inter electrode capacitances of the electrodes attached to the inductor and the container-electrode capacitance which are in parallel therewith) at a frequency substan tially equal to that of the A. C. power source. The elongate tube ET located intermediate the elec

trode edges EEil and EE2, although not necessary for operation of the apparatus, does perform a desirable function. Its presence modi?es the con?guration of the electric ?eld existing between these two opposing elec trode edges so as to minimize arcing and discharge tendencies therebetween. If desired, additional tubing lengths shaped similarly to that of ET can be interposed between ET and the respective opposing electrode edges to further improve the electric ?eld pattern.

It is to be understood that the electron source could be replaced by an ion source, such as that of the PIG type which supplies positive ions at the high-voltage end of the accelerator tube. To accomplish this, the polarity of the high-voltage terminal must be made positive with respect to ground. If this is desired, then all that has to be done to fully accommodate the present apparatus to this purpose (other than modifying the housing EH to provide the ion supply) is merely to reverse each of the recti?ers V1 to V36 in its respective clips so that the anode of V1 is grounded and the cathode of V36 is con nected to the high-voltage terminal, and the other rec ti?er units are connected anode-to-cathode therebetween.

In view of the above, it will be seen that the several objects of the invention are achieved and other advan tageous results attained. As various changes could be made in the above con

structions without departing from the scope of the in vention, it is intended that all matter contained in the above description or shown in the accompanying draw ings shall be interpreted as illustrative and not in a lim iting sense.

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'I claim: , v

1. Voltage multiplication apparatus comprising a pair of metallic electrodes, a source of A. C. power connected to said electrodes, a plurality of recti?er units each hav ing'an anode and a cathode, said units being positioned between said electrodes and being series-connected anode to-cathode between ground and a high-voltage D. C. ter minal, and a corona shield connected at each of, the elec~ trical junctions thereby formed between said recti?er units whereby an A. C. potential of substantially equal amplitude is capacitively coupled across successive pairs of corona shields via the capacitance thereby formed be tween said electrodesand said corona shields.

2. Voltage multiplication apparatus comprising a grounded container, a plurality of recti?er units dis posed within said container, each of said recti?er units having a cathode and an anode, said units being series connected anode-to-cathode between ground and a‘high voltage D. C. terminal, a corona shield connected at each of the electrical junctions thereby formed between said recti?er units, and a pair of intermediate metallic elec trodes interposed between the interior of said container and said corona shields, said electrodes being connected

- to opposite terminals of an A. C. power source. 3. Voltage multiplication apparatus comprising a

grounded container, a pair of opposed metallic electrodes within said container, a source of power connected to said electrodes to supply an A. C. potential therebetween, a terminal electrically connected to said A. C. source at an A. C. potential intermediate that of said electrodes, a plurality of recti?er units each having an anode and a cathode, said units being positioned between said opposed electrodes, said units being series-connected anode-to cathode between said terminal and a high-voltage D. C. terminal,‘a corona shield connected at each of the elec trical junctions thereby formed between said recti?er units whereby an A. C. potential of substantially equal ampli tude is capacitively coupled across successive pairs of corona shields via the capacitance thus formed between said electrodes and said corona shields.

4. Voltage multiplication apparatus comprising a grounded container, a plurality of recti?er units disposed within said container, each of said recti?er units having a cathode and an anode, said units being series-connected anode-to-cathode between ground and a high-voltage D. C. terminal, a corona shield connected at each of the electrical junctions thereby formed between said recti?er units, a condenser connected between each set of alter nate junctions, and a pair of intermediate metallic elec~ trodes interposed between the interior of said container and said corona shields, said electrodes being connected to opposite terminals of an A. C. power source.

5. Voltage multiplication apparatus comprising a grounded container, a plurality of recti?er units disposed within the container, each of said recti?er units having a cathode and an anode, said units being series-connected anode-to-cathode between ground .and a high-voltage D. C. terminal, a corona shield connected at each of the electrical junctions thereby ‘formed between said recti?er units, a pair of intermediate metallic electrodes interposed between the interior of said container and said corona shields, and an inductor adapted to supply an A. C. potential at opposite terminals thereof and having a grounded intermediate tap, said electrodes being con~ nected to said terminals.

6. Voltage multiplication apparatus comprising . a grounded container, an inductor adapted to supply an A. C. potential at opposite terminals thereof, a tap on said inductor connected to ground, a plurality of recti~ ?er units positioned within said container, each of said recti?ers having a cathode and an anode, the cathode of a ?rst of said recti?er units being connected to ground,‘ the anode of a second of said recti?er units being con nected to a high-voltage D. C. terminal, each of said remaining recti?er units being series-connected anode

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1O to-cathode between the anode of said ?rst recti?erunit and the cathode of said second recti?er unit, a corona shield connected at each of the electrical junctions there by formed, a condenser connected between each set of alternate junctions, a condenser interconnecting said ?rst recti?er anode and one of said inductor terminals, a condenser interconnecting the 'other of said inductor terminals to the anode of the recti?er unit connected to said ?rst recti?er anode, and a pair of intermediate metallic electrodes interposed between the interior of said container and said corona shields, said pair of elec trodes being connected to said inductor terminals.

7. A voltage multiplication apparatus as set forth in claim 6 in which the polarity of each of said recti?er units is reversed by connecting the anode of the ?rst unit to ground and the cathode of the second unit to a high voltage terminal. .

8. Voltage multiplication apparatus comprising a grounded container, a pair of metallic electrodes within said container, ?rst and second recti?er units each having a cathode and an anode, said units being series-connected anode-to-cathode at an electrical junction, a plurality of additional recti?er units each having a cathode and an anode series-connected anode-to-cathode between a junc tion thereby formed with said second recti?er unit and a.high-vo_ltage, D. -C. terminal, an inductor adapted to supply an A. C. potential at opposite terminals thereof and having a grounded center tap, a pair of taps on said inductor intermediate said vcenter tap and said induci tor terminals, said inductor terminals being connected to said electrodes, ?rst and second condensers intercon necting the intermediate taps with the ?rst and second said electrical junctions respectively, a plurality of addi tional condensers, one of said additional condensers connected between each set of alternate electrical recti?er unit junctions, and a corona shield connected at each of the junctions between said interconnected recti?er units whereby an A. C. potential of substantially equal amplitude is capacitively coupled to each of said junc tions via the capacitance thereby formed between said electrodes and said corona shields.

9. Voltage multiplication apparatus comprising a grounded container, an inductor adapted to supply an A. C. potential at opposite terminals thereof, a tap on said inductor connected to ground, ?rst and second recti ?er units each having a cathode and an anode, the cathode of said ?rst recti?er unit being connected to ground, said units being series-connected anode-to-cathode at an electrical junction, a plurality of additional recti?er units each having a cathode and an anode series-connected anode-to-cathode between a junction thereby formed with said second recti?er unit and a high-voltage D. C. ter minal, a corona shield connected at each of the electrical junctions thereby formed, a pair of intermediate metallic electrodes interposed between the interior of said con tainer and said corona shields, said pair of electrodes being connected to said inductor terminals, ?rst and sec ond commonly-connected metallic elements respectively spaced from the corona shields connected to said ?rst and second recti?er unit anodes, and means for inde pendently varying the capacitance between each of said elements and its adjacent corona shield whereby the A. C. potential of these last said corona shields may be made substantially equal to the A. C. potentials of the other corona shields.

10. Voltage multiplication apparatus comprising a grounded container, an inductor adapted to supply an A. C. potential at opposite terminals thereof, a ‘tap on said inductor connected to ground, ?rst and second rec~ ti?erfunits each having a cathode and an anode, the anode of said ?rst recti?er unit being ‘connected to a high-voltage D. ,C. terminal, said units being series-con nected anode-to-cathode at an electrical junction, a plural ity of additional recti?er units each having a cathode and an anode series-connected anode-to-cathode between

2,875,391; 1 1

a junction thereby formed with said second recti?er unit and ground, a corona shield connected at each of the electrical junctions thereby formed, a pair of intermediate

etallic electrodes interposed between the interior of said container and said corona shields, said pair of elec trodes being connected to said inductor terminals, ?rst and second commonly-connected metallic elements re spectively spaced from the corona shields connected to said ?rst and second recti?er unit cathodes, and means for independently varying the capacitance between each of said elements and its adjacent corona shield whereby the A. C. potential of these last said corona shields may be made substantially equal to the A. C. potentials of the other corona shields.

11. Voltage multiplication apparatus comprising a grounded container, an inductor adapted to supply an A. C. potential at opposite terminals thereof, a tap on said inductor connected to ground, a plurality of recti ?er units positioned within said container, each of said recti?ers having a cathode and an anode, the cathode of a ?rst of said recti?er units being connected to ground, the anode of a second of said recti?er units being con nected to a high-voltage D. C. terminal, each of said remaining recti?er units being series-connected anode to-cathode between the anode of said ?rst recti?er unit and the cathode of said second recti?er unit, a corona ‘shield connected at each of the electrical junctions there by formed, a pair of intermediate metallic electrodes interposed between the interior of said container and said corona shields, said pair of electrodes being con nected to said inductor terminals, ?rst and second metal lic plates connected to said second recti?er anode and spaced from said electrodes, and means for independently varying the respective effective capacitances established between each of said plates and its adjacent electrode whereby the A. C. potential of saidsecond recti?er anode may be made neutral in relation to ground.

12. Voltage multiplication apparatus comprising an elongate grounded container, a plurality of recti?er units positioned end-to-end within said container and along a longitudinal axis thereof, each of said recti?ers having a cathode and an anode, the cathode of a ?rst of said recti?er units being connected to ground, the anode of a second of said recti?er units being connected to a high voltage D. C. terminal, each of said remaining recti?er units'being series-connected anode-to-cathode between the anode of said ?rst recti?er unit and the cathode of said second recti?er unit thereby forming a series of electrical junctions, a plurality of hollow corona shields connected at each of said electrical junctions, an intermediate hol~ low metallic electrode element interposed between the interior of said container and surrounding each of said corona shields, a source of A. C. power adapted to supply an A. C. potential across a pair of terminals, one of said terminals being connected to alternate electrode elements, the remaining alternate electrode elements being connected to the other terminal.

13. Voltage multiplication apparatus comprising a pair of elongate metallic electrodes, a source of A. C. power connected to said electrodes, a plurality of recti?er units each having a cathode and an anode, said units being positioned between said electrodes and being series-con nected anode-to-cathode between ground and a high-volt age D. C. terminal, an elongate accelerator tube disposed between said electrodes with its longitudinal axis parallel to a longitudinal axis of said electrodes, opposite ends of said tube being connected to ground and the high voltage D. C. terminal respectively, and a corona shield connected at each of the junctions thereby formed be tween said interconnected recti?er units whereby an A. C. potential of substantially equal amplitude is capacitively coupled across successive pairs of corona shields via the capacitance thereby formed between said electrodes and said corona shields. '

’ . 14. Voltage multiplication apparatus as, set forth in

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12 claim 13 in which said recti?er units are disposed in a zig-zag con?guration between said electrodes.

15. Voltage multiplication apparatus comprising a grounded container, a plurality of recti?er units within said container, each of said recti?er units having a cathode and an anode, said recti?er units being con nected anode-to-cathode between ground and a high voltage D. C. terminal, a corona shield connected at each of the electrical junctions thereby formed between said recti?er units, a pair of intermediate metallic electrodes interposed between the interior of said container and said corona shields, a source of power connected to said electrodes to apply an A. C. potential thereacross, ?rst and second metallic plates spaced from said electrodes and electrically connected together through the primary of a transformer, said transformer primary having an intermediate tap connected to said high-voltage D. C. terminal.

16. Voltage multiplication apparatus comprising a grounded container, a plurality of recti?er units within said container, each of said recti?er units having a cathode and an anode, the cathode of a ?rst of said recti?er units being connected to one of said terminals, the anode of a second of said recti?er units being connected to a high voltage D. C. terminal, each of the remaining recti?er units being series-connected anode-to-cathode between the anode of said ?rst recti?er unit and the cathode of said second recti?er unit thereby forming an electrical junction between adjacent recti?er units, a corona shield connected at each of said electrical junctions between said recti?er units, and a pair of intermediate metallic electrodes interposed between the interior of said con tainer and said corona shields, a source of power con nected to said electrodes to apply an A. C. potential thereacross, at least two of said corona shields having means associated therewith for independently varying the capacitance between each of the last said shields and its adjacent electrode whereby the amplitude of the A. C. potentials of such shields may be varied.

17. Voltage multiplication apparatus comprising a pair of opposed metallic shells having their respective edges spaced apart, a source of electric power connected to said shells to apply an A. C. potential thereacross, a plurality of recti?er units each having an anode and a cathode, said units being positioned between said shells and being series-connected anode-to-cathode between ground and a high-voltage D. C. terminal, and a corona shield connected at each of the electrical junctions thereby formed between said recti?er units whereby an A. C. potential of substantially equal amplitude is capacitively coupled across successive pairs of corona shields via the capacitance thereby formed between said shells and said corona shields.

18. Voltage multiplication apparatus as set forth in claim 17 which includes at least one elongate metallic element positioned between the spaced apart opposed edges of said shells.

19. Voltage multiplication apparatus as set forth in claim 18 in which the opposing edges of said shells are rounded and smooth and the elongate metallic elements are smooth and tubular.

20. Voltage multiplication apparatus as set forth in claim 19 in which the shells, recti?er units and corona shields are enclosed in a grounded container.

21. In voltage multiplication apparatus including a grounded container, a plurality of recti?er units disposed within said container, each recti?er unit having an anode and a cathode, said units being series-connected anode to-cathode between ground and a high-voltage D. C. terminal, and a corona shield connected at each of the electrical junctions thereby formed between said recti?er units; a pair of intermediate metallic electrodes interposed between the interior of said container and said corona shields, and an inductor adapted to supply an A. C. potential at opposite terminals thereof, said pair of elec

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trodes being connected to said inductor terminals, the inductance of the inductor and the capacitance between the grounded container and the electrodes and the ca pacitance between the electrodes forming an LC circuit having a resonant frequency substantially equal to the frequency of said A. C. potential.

22. Voltage multiplication apparatus as set forth in claim 21 which further includes an accelerator tube con nected between said terminal and ground and adapted to produce a beam of charged particles, and in which the 10 21619502

‘[4 inductor is toroidal in con?guration whereby eddy cur rents in the surrounding container and other adjacent metallic components are substantially avoided and de?ec tion of the said beam by the inductor magnetic ?eld is

5 substantially prevented.

References Cited in the ?le of this patent UNITED STATES PATENTS

Walker et a1 __________ __ Nov. 25, 1952