US2608664A - Method of generating an accurately focused beam of charged particles - Google Patents

Method of generating an accurately focused beam of charged particles Download PDF

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US2608664A
US2608664A US128084A US12808449A US2608664A US 2608664 A US2608664 A US 2608664A US 128084 A US128084 A US 128084A US 12808449 A US12808449 A US 12808449A US 2608664 A US2608664 A US 2608664A
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tube
voltage
particles
envelope
charged particles
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US128084A
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Graaff Robert J Van De
Buechner William Weber
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Research Corp
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Research Corp
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Priority to BE474550D priority Critical patent/BE474550A/xx
Priority claimed from US617036A external-priority patent/US2517260A/en
Priority to FR948593D priority patent/FR948593A/fr
Priority to GB155/48A priority patent/GB695441A/en
Priority to GB29326/52A priority patent/GB695539A/en
Application filed by Research Corp filed Critical Research Corp
Priority to US128084A priority patent/US2608664A/en
Priority to US133972A priority patent/US2559526A/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H5/00—Direct voltage accelerators; Accelerators using single pulses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/02—Vessels; Containers; Shields associated therewith; Vacuum locks
    • H01J5/06—Vessels or containers specially adapted for operation at high tension, e.g. by improved potential distribution over surface of vessel

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  • This invention relates to almethod of generating an accurately focused beam of charged particles.
  • the said method involves the employment of a highwoltage hlg'il -VZLCUUIH tube for producing accurately focused beam of swift particles, either electrons orlions.
  • a highwoltage hlg'il -VZLCUUIH tube for producing accurately focused beam of swift particles, either electrons orlions.
  • The-in vention makes possible an improvement in highwoltage radiography and may be carried out in or by the use of high-voltage high-vacuum tubes involves new principles of operation.
  • the invention' may be useful in such fields as nuclear physics, cancer therapy, radiography, high-voltage X-rays, the rectification of highvoltage currents, the production of cathode rays; the sterilization of foods, drugs and other substances, the irradiation of matter, and the acceleration of electronsfor high-voltage electron microscopes.
  • Our invention herein claimed may be defined as a method of establishing, maintainingand transmitting a continuous, uninterrupted, accurately-focused beam of chargedparticles in a substantially uniform, high-voltage high-vacuum, electrostatic fi'eldwhich comprises the following stepsfl (1') establishing and uninterruptedly main-- taining a substantially uniform, high-voltage, high-vacuum, electrostatic field in'a suitable envelope, (2) establishing,uninterruptedly main taining and uninterruptedl-y transmitting a conation of the hlgh voltage high-vacuum substantially uniform electrostatic field; (3,); by the uninw terrupted maintenance of such substantially uniform electrostatic field, accelerating such continuous beam of charged particles in its passa e from such emission area onwardthroughout such substantially uniform, electrostatic field to such electrode target, and (i4) accurately focusing Said continuous beam of charged particles throughout its passage from such emission area to; such electrode target, l
  • The. high-voltage high-vacuum tubev to which our present invention of a novel method relate and by which it is preferably practiced is a 00.n-
  • Such apparatus comprises a highwoltage tube of insulating materialwhich has electrodes adapted to be connected to a suitable source of high potential, such as a high-1 voltage electrostatic generator.
  • a suitable source of high potential such as a high-1 voltage electrostatic generator.
  • At one end of the tube being the upper endas shown in the drawings, is located means providing an emitting source, which means, in the present disclosure, is afilament having a plane emitting surface of relatively minute area.
  • the wall of thetube comprises electrode rings owing-like disksor centrally open metallic diaphragms arranged along the tube, spaced by insulationsuch as glass, and connected in suitable manner to.
  • the corresponding elem trodesina high-voltage generator in such a way that the potential'gradient downthe tube is-uni'- 'tinuous-beam of chargedpar ticles froma source ofchar ged particles at one end of such envelope to an 'electrod'etarget'at the' other end of said envelopethrough such high-voltage for the operform, and in such a way that equal-stepsin the voltage between successive electrodes are-pro vided. Thuathere is provided in the tube s, substantially uniform electrostatic field.
  • An exceedingly important feature of the invention with respect tothe novel rn'ethod is the 3 provision and use of a substantially uniform electrostatic field which is in contrast with the use of a non-uniform electrostatic field, as has generally been the case in tubes that have been used in the past, as, for example, the tube disclosed in the United States patent to John G. Trump, No. 2,182,185, dated December 5, 1939.
  • the focusing of the electron beam by the herein disclosed apparatus for practicing the invention, and by the use of a substantially uniform electrostatic field, is less sensitive to variations in the potential applied to the various tube electrodes than is the case in tubes employing nonuniform electrostatic fields.
  • tubes of the prior art were made for operation with impulses where the voltage was on for periods of the order of only a few microseconds each, and in order to pass sufiicient average currents they had to have high instantaneous currents.
  • a two-inch diameter hole is cut out or is otherwise provided at the center of each of the metallic ring-like electrode disks or diaphragms provided along the extent of the tube. Since each successive electrode ring or diaphragm is more and more positive from the filament toward the target, the electrons or negatively charged particles are attracted down the tube and strike the target with an energy corresponding to the full generator voltage. The conditions are reversed when positive ions are to be accelerated. In their passage down the tube, they tend to follow the lines of electric force, and in the high-voltage vacuum tube herein disclosed, the lines of force are straight lines.
  • the structure herein disclosed is equally well suited for the acceleration of either'positive ions or negatively charged particles. This follows since themanner of construction and the use make the tube completely symmetric. Thus, it is possible to accelerate charges in either direction through the tube without the necessity of having to change the arrangement of potentials on theelectrodes.
  • the electrons are emitted at-the negative endof the, tube and are accelerated toward the electron-collecting target; while atthe same timepositive ions are to be produced at the positive end of the tube and accelerated toward the region of the cathode.
  • the" diameter'of the beam of charged particles after passingthrough the tube is proportional to the size of the source of the charged particles.
  • the definition in the radiograph depends critically upon the spotsize, and hence it is very desirable that the efiective portion of the filament be as small as possible.
  • the focused spot upon the target can be smaller than 0.01 of aninch in'diameter. .To obtain radiographs of thick. sections having good definitionpthe: size. of the. focal spot mustbe veryfsmall so that the. X-rays will be emanating from apoint source. Thick metallic sections of objects requiring on the order of.
  • the high voltage tube operates in conjunction with an. electrostatic. gene erator producinga potentialof theorder of two million volts.
  • the use of such constantpotential hasbeen found necessary in order to obtain and to maintain the said extremely fine focusing referred to and to provide optimum conditions for heat dissipation at the focal point.
  • the target upon which the electron beam is focused is a thick disk of gold used in association with high pressure water cooling.- Theuse of such a relatively thick target disk permits operation with the target spot in molten condition without, however, melting entirely through the. disk. It becomes possible as. a result to make full use of the high intensity, sharply concentrated, electron beam andthus to obtain X-ray pictures of greatly improved quality.
  • Fig. 2 is atransverse or cross-section upon the line 2-2.of Fig.1; 1
  • Fig.3 isa detail in, vertical central section through the lower end of the filament? and the surrounding guard ring;
  • i Fig. 4. is a view similar to Fig. 3 but on arlarger scale and representing only a portion of the guardring; l
  • Fig. 5 is abroken-away detail inside elevation of a portionrof the high-voltage vacuum tube shown inFig. 1,with' a diagrammatic indication of the connections between the electrode rings .oflthewtube and corresponding electrodes of'an electrostatic generator; l .2: (dis :a. broken-away detail in vertical sec.- .ltionlcf .azmodified form of the electrode: rings of thetshigh voltageatube at thalower portion of saidwtube; and ⁇ - l v Figs 7v is alvertical crossesectional view; of. a
  • a high-voltage vacuum, tube consisting of a column composed of; glass rings and of metal electrode rings or ring-like diaphragms or disks suitably welded together in alternation throughout the column, a. part only of which is shown, in a manner and by means not horeinlnecessary to disclose in detail, the present invention being directed broadly to: the herein disclosed method by which a. uniform electrostatic fieldis providedand maintained inthetube or column, whereby in some applications, when the method is practiced by an apparatus usedas an X-ray tube, the electron. beam is controlled and compelled to strike the target. at. apoint. of, exceedingly small. diameter.
  • This configuration of electric field is. also well suited for the acceleration, and focusing of ion beams.
  • the glass rings are respectivelyindicated at. l, and the metal. electrode ringa'cen- *trally; open diaphragms or disks at 2.
  • The. said metal rings 2 or the like. are. electrode rings'and lie accurately. placed in planes perpendicular; to the axisofthe tube, and they are placed atequal distances apart, as, for example, one-third of an inchin the present disclosure.
  • thetube or column is represented as broken away be cause of the necessity of presenting a; viewer the complete tube in a single figure; While, obvious:- ly the method is not concerned with any particular size or proportion of parts of thesap paratus by which the method is.
  • the diameter of the opening in each ring is twoinches, andthe outside diameter of the-tube. or column is three. inches.
  • the outerredge of each of the metal electrode rings 2 is substantially co-terminous with the outer edge. of the glass rings i.
  • the distance from the line 3 to the top ofthe dome-like. glass insulation is aboutsiX inches.
  • these dimensions may be varied asjfound suitable, and the scope; and principle of our method are in no wiserestricted by this recitae tion of dimensions of apparatus. for practicing ourmethod.
  • the glass insulation which holdsthemetal disks 2 in correctrelative alignment and which consists of the glassrings i. may have on its inner surface an uncontrolled distribution of electric charge which wouldtend to'distort in a random and uncontrolled manner the uniformity of the electrostatic field within the main region of the tube.
  • the distributing :infiuence of these charges is reduced to. a negligible' degreeby the shielding effectiof. the metal rings 2,which.extend inward from-the glass wall composed of theglass rings I towardtheaxis of the tube to a sufficient extent to produce the desired shielding.
  • the fact that thegap. between adjacentmetal rings 2 is relatively small,
  • each metal ring being in the present disclosure one-third of an inch less the thickness of one disk, the actual structure having the other proportions above specified, makes it possible to obtain the desired shielding effect with only a relatively, narrow ,region or portion of each metal ring extending inwardly beyond the inner surface of the glass wall composed of the multiplicity of glass rings I.
  • the amount that each metal ring must project inward from the glass wall of the tube must be approximately thesame as thelength of the gap between next adjacent metal rings 2. all along the glass wall of the tube.
  • the gap between the next adjacent metal rings 2 is small is in itself advantageous, inasmuch as it reduces the amount that each metal ring 2 must extend inward beyond the inner surface of the glass wall.
  • the fact that the metal rings 2 are close together makes it possible to use more of the internal space in the tube for the beam of charged particles.
  • Certain metal rings 2 of the tube or column which are indicated at 2a in Fig. 5, are connected to corresponding electrodes of the generating apparatus which may take the form of a high voltage electrostatic generator, as indicated in the diagrammatic part of Fig. in such a way that the voltage between the successive electrodes of the tube is the same.
  • Fig. 5 a few of the generator electrodes are represented at 21'), and a portion of the resistors at 20. As shown, every'third electrode ring 2 of the tube is connectedito a corresponding electrode of the generator, which generator electrodes are an inch apart.
  • Each of the metal electrode rings 2 in Fig. 5, as well as in Fig. 1, has its outer edge substantially co-terminous with the outer edge of each of the glass rings I.
  • the acceleration of an electron beam in a uniform field has many basic advantages as contrasted with the more usual methods of acceleration in strongly non-uniform electric fields.
  • the filament of the tube from which emanates the electron beam is indicated at ID in Fig. 1, and is shown in detail in Figs. 3 and 4.
  • the said filament is composed of tungsten, and is of a hairpin type. It has the apex of the bend ground off, as indicated at H in Figs. 3 and 4, in order to provide a plane emitting surface ll of relatively minute area.
  • the diameter of the filament in the unreduced portion thereof is 0.010, and at the ground-off portion at the apex of the bend it is desirably less than one-half such thickness, thereby insuring an intense heat at said groundoff portion when the apparatus is in use, being the plane emitting surface of the electrons.
  • the cross section of the filament being the least at the ground-off portion, the resistance is the greatest at that area.
  • the filament [0 has placed in conjunction therewith and encircling the same, a guard ring [2, shown enlarged andzin part injFig'.'4,'which has a plane lower surface lying exactly in' the same plane as the emitting plane'of the filament.
  • the said guard. ring 12 hastherein'a central through-opening 12a, which is approximately 0.040 of an inch in diameter and within which the apex of the bend, constituting the plane emitting surface II, is symmetrically positioned.
  • the filament and the surrounding guard ring are usually maintained at approximately the same potential. However, by making the potential of the guard ring substantially more negative than that of the filament,'the gridaction of the guard ring can be used to reduce, or even entirely cutoff, the electron stream.
  • the gridaction of the guard ring can be used to reduce, or even entirely cutoff, the electron stream.
  • wires 10a and 12b leading respectivelyv from the filament Ill and from the guard ring l2. to the positive and negative sides of a. battery 13.
  • the over-all focusing properties of the tube as a whole may be affected by providing relatively small'voltage differences between the filament and. the surroundingguard ring.
  • the filament andlthe guard ring have been generally'operate'd at the same potential, there are some occasions when itis desirable to operate the filament and guard ring at somewhat'differentpotentials.
  • the .beam of electrons proceeds in a substantially straight line along the tube or column "from the point of emission, as indicated at I3, resulting in a beam whose cross section in the region nearthe top of the tube corresponds closely to theisize and shape of the emitting plane, and wherein the energy of the individual charged particles is substantially identical.
  • Such a beam may readily be focused by a relativelyweak magnetic field on an extremely concentrated spot, as by an electric magnet I4, the arrangement constituting a magnetic lens, the magnetic lines of force whereof are indicated at Ma.
  • the electron beam is focused on a target which, in the disclosed embodiment of apparatus for practicing our method, is a thick metal disk I5 of gold, used in association with a high pressure water-cooling jacket, indicated at I6, and provided with a water inlet I1 and water outlet I8.
  • the target I5 is a gold disk one-quarter of an inch in thickness in the disclosed apparatus for practicing our method.
  • Gold has a high heat conductivity and also chemical and physical properties such thatit can be repeatedly melted and allowed to freeze without appreciable oxidation or change in physical structure.
  • the high voltage vacuum tube herein illustrated and described constitutes one embodiment only of apparatus for practicing our novel method, and presents the same in a simplified mechanical construction.
  • Certai-n mechanical design features of the tube herein disclosed such as areconcerned with a vacuum-tight tube or column having the necessary insulating characteristics and enabling it to withstand the high pressures involved, as, for example, an air pressure of from 200 to 400 pounds per square inch, have, in the further development of our novel method herein described and'claimed, been ably developed by Machlett Laboratories, Incorporated, to whichhas issued United-States Patent/No. 2376,4351, dated May 22, 1945, -in the names of "Raymond R. Machlett and Joseph W.
  • the invention herein disclosed and claimed is particularly directed to establishin and maintaining a uniform electrostatic field for accelerating and focusing charged particles, and to carry out such method we provide an arrangement of electrodes particularly suitable for establishing andmaintaining such an electric field.
  • a filament of a very small effective area and a relatively thick gold target As a part of the apparatus, but which is not herein claimed, we provide a filament of a very small effective area and a relatively thick gold target.
  • the described construction has the additional advantage of shielding the insulating walls of the tube, and breaking up the total applied voltage so as to facilitate problems of insulation.
  • the high-voltage vacuum tube herein disclosed for practicing our novel method is adapted to the acceleration and focusing of charged particles, andin the case of electrons this beam isextremely concentrated.
  • the disclosure includes charged particle accelerating means providing a uniform accelerating field, thus, reducing to a minimum the dispersion of the charged particles throughout their travel. Therefore, a large number of accelerating sections are provided, the number used inpresent practice for two million volts being approximately 180, thereby providing uniform accelerating steps of-l2,000 volts each.
  • the electrode disks welded into the wall of the tube in alternation with theinsulating disks to constitute the entire wall of the tube comprise sixty groups of metallic electrodes, each such group consisting of three electrodes, and only one of said electrodes of which each such group is composed is directly electrically connected to a corresponding electrode of a high-voltage electrostatic generator, so that the voltage between the successive disks of the tube is the same.
  • FIG. 6 there is represented upon an enlarged scale a slight modification of the shape or form of certain of the electrode rings indicated at 2 in Figs. 1 and 5.
  • Fig. 6 there is shown in cross section a small portion only of the lower part of the tube.
  • the glass rings are indicated at I, as in Figs. 1 and 5.
  • the electrode rings are indicated at I9, and each of them has a much thickened inwardly extending portion 20 of streamlined form and constituting what may be termed .a .tear drop section.
  • each portion 28 is of annular form having extending outwardly therefrom the thin .rimlike part I9, thus constituting an annular flange received between the next adjacent glass rings I.
  • Electrode rings of tear drop shape are employed only at the lower end of that part of the tube composed of alternating glass rings and metal rings.
  • tear drop construction of electrodes may have advantages including the following: (1') improved electrostatic shielding of the inner wall of the insulating envelope of the tube; (2) increased shielding of the electron beam inside the tube against the disturbing eifect of irregular discharges on the glass wall of the tube; (3) by constructing the internal thick electrode of some suitable magnetic material, such as soft iron, the electron beam can be shielded with greater effectiveness from disturbing external magnetic fields; (4) in certain special cases where the electric field may locally depart from the uniform condition, as, for example, at the lower end of the vacuum tube shown in Fig. 1, the rounding of the electrodes would prevent the concentration of the electric field which occurs with the use of ring-plane electrodes 2 in this local region.
  • the potential gradients are reduced to a minimum makes it possible to apply to the tube its rated voltage even though the vacuum region of the tube may be temporarily filled with gas at the pressure surrounding the outer portion of the tube. This may be desirable for certain special tests, or when two or more tubes are connected in parallel with the same voltage source. In case of vacuum difficulty with one of the tubes, it could be allowed to fill with gas so that the other tube may continue to be used at full voltage.
  • the substantially uniform, electrostatic field provided throughout the transverse and longitudinal extent of the enclosed space that is created and is undisturbed and undistorted, in accordance with andin carrying out the herein disclosed method cooperates and co-acts, as stated, in focusing the beam of charged swift particles, and also cooperates and co-acts in effecting the reaching of higher voltages, and provides for carrying out the herein disclosed method by apparatus of greater compactness and materially differing in structure among themselves.
  • the region along the axis of the high-voltage enclosed space (herein shown as an accelerating tube) is left open and unobstructed so that the desired beam of charged swift particles can be and is accelerated by our method along the axis of such enclosed space, that is, along the axis of the insulating portion of the said tube.
  • the potential gradient can be kept at relatively very low value at electrode surfaces or areas in vacuum existent in or at the wall of the said enclosed space or tube (the form or structure of which may differ in variousapparatus carrying out our method), particularly in the region adjacent to the open axial path through the tube or enclosed space.
  • This relatively very low value of the potential gradient can be made to approach the theoretical limit which is the ratio of the voltage across the tube or enclosed space to the length thereof, which may be called the average potential gradient along the tube.
  • the low value of the potential gradient at electrode surfaces or areas, or surfaces at controlled potentials, at or upon the wall of the enclosed space is important because it reduces the auto-emission, or field currents, of electrons at these surfaces or areas. It is also important because it reduces the secondary emission of 7 charged particles due to the impact of stray highvoltage particles on such electrode surfaces or areas or surfaces at controlled potentials.- Secondary emission is known to be a most important factor in the breakdown of high-voltage tubes.
  • trostatic field is applied primarily to the axial region of the enclosed space or tube where the desired beam of charged swift particles is accelerated by the herein disclosed method, and also to the electrode surfaces of the wall of the enclosed space or tube in the region adjacent to and surrounding such axial region.
  • the electrode surfaces at the wall of the enclosed space or tube having high voltage tend to contribute secondary particles which may cause high-voltage breakdown, and as herein disclosed we shield the Wall from deterioration due to stray radiation.
  • the impact of stray-high-voltage particles with electrode sur-' faces at the wall of the enclosed space or envelope is largely in the normal direction, thus minimizing the production of secondaries, and furthermore, the potential gradients on the electrode surfaces exposed-to the bombardment of stray high-voltage particles do not substantially exceed a value equal to the ratio of the enclosed space or tube voltage to the enclosed space or tube length, and, moreover, the potential gradients on the electrode surfaces at the wall of the enclosed space or envelope do not substantially exceed the average potential gradient along the tube or enclosed space or envelope.
  • the multiplicity of metal electrode rings orconducting electrode members 2 are for the purpose primarily of carrying out the step of our novel method, namely, that of establishing a substantially-uniform elec- 13 trostatic field throughout the said tube, and in doingso we do not extend the outer edges of said members materially beyond, but, on the contrary, keep their outer edges substantially flush with, the outer edges of the insulating members I, and we avoid any construction which would cause, within the tube structure, any considerable amount of stored electric energy, as this would prevent the carrying out of our method.
  • Fig. 7 is sufiiciently representedian improved high-voltage rectifier possessing, many of the principles set forth in the foregoing part of the specification, and which presents one of the most important aspects of the invention herein disclosed and by which also our novel method is practiced.
  • Such rectifier is shown in its relation to a source ofalternatingvoltage of about a hundred volts.
  • the cathode could be constructed by providinga large number of closely spaced, parallel wires heated by the passage of an electric current.- i i .
  • the outer, herein vertical, wallor main cylindricalportion of the rectifieris preferably composed, as in Fig l, of alternate insulating rings 23 preferably of glass, ancl'goi'tmetal electrodes 24,-which may be simila-r to those shown at 2 in Figl l and possess the characteristics, purposes andadvantages thereof, r
  • Jackets for water cooling are provided at the upper and lower ends of the rectifier, as indicated at 25 and 26, and theouterrsur-face of the main cylindrical portion of the rectifier will, if necessary, be cooled by circulating oil or gas.
  • the electron stream, so marked, is indicatedat Z1, and theresiston at 28,rwhich is indicative of a suitable" generator, such as would be employed with the apparatus shown inFig. l. .A source of alternating voltage,.such as a transformenis diagrammatically indicated at 29 in proper relation to the high voltage rectifier
  • a suitable generator such as would be employed with the apparatus shown inFig. l. .A source of alternating voltage,.such as a transformenis diagrammatically indicated at 29 in proper relation to the high voltage rectifier
  • the 'multi-sectioned construction one embodi mentlof which is herein disclosed,.makespossible the satisfactory. insulation of extremely high inverse voltages, whil-esome of the principles-of electron flow, as described in the preceding part of the specification, with relation to X-ray tubes, together with other. aspects of the construction, make possible the flow, or large electron currents inthe .desireddirection in thecarrying out of our novelmethod.
  • the maximum potential gradient on the electrodes 1 in vacuum is a minimum, and never exceeds a value approximately equalto the ratio of the maximum inverse voltageacross the rectifier to the length ofthe electron path within the rectifier.
  • That method of directing, accelerating and focusing a beam of charged particles, either electrons or ions, from a point of injection-thereof so that they are caused to travel invery close parallel paths 'to the point of use thereonallhaving the same energy comprisingth-e following steps: ,(1) providing and maintaining averyhigh vacuum within and throughout an elongated closed space; (2) providing and maintaining of such beam of charged particles to the point of use thereof at substantially the area" of termination of such substantially uniform electrostatic field; (4) and injecting from asuitable operatorcontrolled source of electrons or ions such a beam of charged particles immediately and continuously into such substantially uni-form .electrosta tic field maintained in such very high vacuum, so that such beam is accelerated in saidsubstantially uniform electrostatic field to its point of 'useywhereby, through the presence and action nuclear physics, cancer therapy; radiography,
  • trodesof a high voltage generatonso as thereby;
  • velocities as such chargedparticles may have;

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Particle Accelerators (AREA)
  • X-Ray Techniques (AREA)
US128084A 1945-09-18 1949-11-18 Method of generating an accurately focused beam of charged particles Expired - Lifetime US2608664A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
BE474550D BE474550A (fr) 1945-09-18
FR948593D FR948593A (fr) 1945-09-18 1947-06-27 Perfectionnements aux procédés et aux appareils pour la production d'un faisceau de particules chargées
GB155/48A GB695441A (en) 1945-09-18 1948-01-02 Improvements in or relating to apparatus for generating a beam of charged particles
GB29326/52A GB695539A (en) 1945-09-18 1948-01-02 Improvement in or relating to method of generating a beam of charged particles
US128084A US2608664A (en) 1945-09-18 1949-11-18 Method of generating an accurately focused beam of charged particles
US133972A US2559526A (en) 1945-09-18 1949-12-20 Anode target for high-voltage highvacuum uniform-field acceleration tube

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US617036A US2517260A (en) 1945-09-18 1945-09-18 Apparatus for generating an accurately focused beam of charged particles and for related purposes
US128084A US2608664A (en) 1945-09-18 1949-11-18 Method of generating an accurately focused beam of charged particles

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Publication number Priority date Publication date Assignee Title
US2945980A (en) * 1954-07-02 1960-07-19 Applied Radiation Corp Vacuum tube
US2953701A (en) * 1957-09-05 1960-09-20 High Voltage Engineering Corp Sealed-off diode with electron emitting anode
WO2012025136A1 (fr) * 2010-08-27 2012-03-01 Ge Sensing & Inspection Technologies Gmbh Tubes à rayons x à microfoyer pour un dispositif à rayons x à haute résolution

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US2005021A (en) * 1929-07-23 1935-06-18 Brasch Arno Vacuum tube
US2145727A (en) * 1937-12-28 1939-01-31 Gen Electric High voltage discharge apparatus
US2182185A (en) * 1938-06-24 1939-12-05 Research Corp High voltage ionic discharge device
US2264274A (en) * 1939-04-04 1941-12-02 Emi Ltd Cathode ray tube
US2336774A (en) * 1941-08-18 1943-12-14 Gen Electric X Ray Corp X-ray tube
US2376439A (en) * 1943-06-18 1945-05-22 Machlett Lab Inc Insulating structure
US2433682A (en) * 1944-10-31 1947-12-30 Philco Corp Electron focusing apparatus
US2460201A (en) * 1946-12-20 1949-01-25 Research Corp Laminated envelope structure for electron discharge devices
US2517260A (en) * 1945-09-18 1950-08-01 Research Corp Apparatus for generating an accurately focused beam of charged particles and for related purposes

Patent Citations (9)

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Publication number Priority date Publication date Assignee Title
US2005021A (en) * 1929-07-23 1935-06-18 Brasch Arno Vacuum tube
US2145727A (en) * 1937-12-28 1939-01-31 Gen Electric High voltage discharge apparatus
US2182185A (en) * 1938-06-24 1939-12-05 Research Corp High voltage ionic discharge device
US2264274A (en) * 1939-04-04 1941-12-02 Emi Ltd Cathode ray tube
US2336774A (en) * 1941-08-18 1943-12-14 Gen Electric X Ray Corp X-ray tube
US2376439A (en) * 1943-06-18 1945-05-22 Machlett Lab Inc Insulating structure
US2433682A (en) * 1944-10-31 1947-12-30 Philco Corp Electron focusing apparatus
US2517260A (en) * 1945-09-18 1950-08-01 Research Corp Apparatus for generating an accurately focused beam of charged particles and for related purposes
US2460201A (en) * 1946-12-20 1949-01-25 Research Corp Laminated envelope structure for electron discharge devices

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2945980A (en) * 1954-07-02 1960-07-19 Applied Radiation Corp Vacuum tube
US2953701A (en) * 1957-09-05 1960-09-20 High Voltage Engineering Corp Sealed-off diode with electron emitting anode
WO2012025136A1 (fr) * 2010-08-27 2012-03-01 Ge Sensing & Inspection Technologies Gmbh Tubes à rayons x à microfoyer pour un dispositif à rayons x à haute résolution
CN103189955A (zh) * 2010-08-27 2013-07-03 Ge传感与检测技术有限公司 用于高分辨率x射线设备的微焦点x射线管
US9153408B2 (en) 2010-08-27 2015-10-06 Ge Sensing & Inspection Technologies Gmbh Microfocus X-ray tube for a high-resolution X-ray apparatus

Also Published As

Publication number Publication date
GB695441A (en) 1953-08-12
GB695539A (en) 1953-08-12
BE474550A (fr)
FR948593A (fr) 1949-08-04

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