US 2493606 A
Description (OCR text may contain errors)
mented Jan. 3, 195o A. 2,493,606
UNITED STATES 'PATENT OF FICE' l X-RAY APPARATUS Frank Waterton, Manchester, -England, assgnor, Aby mesne assignments, to General Electric Company, a corporation of New York Application .June 11, 1946; SerialN;o.'67-3,',7r22 In Great Britain J unell,` 1945 2 claims. (C1. 25o-148') 1 i 2 The presentinventionrelates to X-ray apparahousing 1I. and the fixed member of a roller beartus which is constructed to be capable `of susing 9 is mounted directly on the Wall of the tained and `powerful output of X-rays for diaghousingl. The cathode and anode assemblies are nostic, crystallographic, industrial or other purmounted on a driving shaft II which is connectposes In such apparatusit is necessary to proed for rotation toan yelectric motor I2, the latter vide against excessive heating of `the target area being supported as indicated on Wall extensions which may cause fusion and Vaporation of target I3 of the enclosing housing. The motor is inmetal. The .object of the invention is toprovide Sula-ted from the X-ra-y cathode by .an insulated an limproved apparatus wherein constant .shiitcoupling I 4, The space surrounding the motor ing ofthe .area vof impingement of the cathode lo II2 and the Icoupling I4 may or may not be filled rays on thetarget occurs, thus increasing the area withI insulating liquid` of- X-iay ygeneration on the `target and .conse- The `cathode assembly comprises a funnelquently of heat dissipation without increasing the shaped envelope I5l which is ysupported Within a size of--thefocal-spot; cradle I-G of" similar shape. The outer thin rim The mpiOVed X-iay equipment f the present 15 of the ared'endof the metal` envelope 'I5 is sealed inventionis oonstructed'to provide `for simultanetothe glass insulator `TJ.v On the small bore ous rotation of both the cathode and the anode tubular end of the rotating cradle It aremou-ntstructures Within a stationary sealed housing coned the electric `rotor coils Hv and the magnetic taining an insulating uid- My inVeni'fiOn d150 incore lil" of an electric generator. The stator coils cludes improvedstructural features, such as prot8 andthe'annular'xed magnetic core I8 of the vision of means within the housing fOr defleine genera-terme lmounted on the wall or the envelope the beam of cathode rays out of its normal axial I, the core having inwardly directed salient field POSiiiDn- Wilendiie benin 0f iihode rays S held poles carrying the exciting windings. An electric Siilinafy in 2 deiiei'led' POSii'fiOn and the and@ current of suitable voltage for heating the cathrotates the heating eiect of the focal area is disode filamenti@ to electron emitting temperature DeilSed'OVeia reiaiileiyiarge annular area on the isA furnished by the generator during rotation. target whereby the iOad capacity 0f the Xeray The generator is connected to the-cathode by conapparatus becomes Substantially greater than duc-tors l2.1- and .22s, the former being shown lonly that of .an apparatus with .a xed focal area in part las the "circuit is completed 'through the kOther features of novelty in the improved .5o mei-,amc cra/dile |.3 X-ray apparatus described herein will be pointed Advantageously the X-ray tube is releasably out in the appended @I aiInS- secured in its cradle I6, for example, by screwing As will appear hereinafter one of the novel feathe cathode end of the cathode assembly into a tures of the present device Consists in the DTO" correspondingly screw-threaded portion of the vision of means for heailng the Cathode by Cufcradle I6. One end of the filament is connected rent generated Within the enclosing envelope by With said screw-threaded part of the envelo e a generator which is activated by the rotation of which in tum is @armed The other end of an X-ray generating device Novelty target C001' filament is connected to a terminal clip 23 adapting constructions also are included.
ed to be engaged by a spring-pressed contact 24 The accompanymg drawing 1s a longltudmal 40 which is connected to one lead of the rotor windsection of an embodiment of my invention.
This drawing shows a sealed housing consisting mgl: the other lead of the latter bemg earthwof a tubular main portion I and an end cap 2 he anoie may be Constructed as Shown of an which is bolted to the portion I as indicated at mwardly dlrectefi Substantlauy Cup'sha'ped mem 3 and The housing may consist of metal] or 45 ber, which conslsts partly of a shell 6 of copper, other suitable material. In the tubular portion I or other metal o f good heat Conductivity Sufis mounted a rotatable X-ray structure consisting rounding circulating Varies 25 and a Cathode-ray 0f a cathode assembly 5 and an anode assembly recelvmg layer 21 of tungsten, or other suitable The assemblies are mounted on a shaft and refractory metal. Itis also contemplated to supare connected to one another at the anode end plement the tungsten fing, by other metal targets,
by a reentrant insulator 'I which ordinarily confoi' example Chromium, a ferrOuS ailOy, 0r even a sists of glass, thereby forming a sealed envelope. Coppel Surface, and t0 arrange for the electron This rotatable X-ray device is supported on bearbeam t0 be mOi/ed t0 a desired target Surface by ings 8 and 9. The sleeve bearing 8 is supported on altering the OrientaiOn 0f a magnetic coil 28 a diaphragm I0 extending from the walls of the 65 whereby the electron beam s focussed and deected or by` altering the excitation of the coil 28.
cuit is completed through the grounded casing I.
The space within the external casing is filled with mineral oil or other suitable insulating liquid which envelops the rotating X-ray device. Heat l is abstracted by circulation of a cooling medium through the cooling coil 35 which is immersed in the cooling medium. Attached to the anode 5 and thus rotating with it are disposed radial Vanes 26 forming an impeller adapted to enforce circulation of oil through the tubular bale 36 against the back of the anode. The oil may be arranged to pass into the interior of the hollow baille 25 by openings 36 and from thence out through opening 39 into the narrow space between th-e baille 36 and the reentrant tubular attachment which supportsrthe anode. Bale 36 is supported from conductor 3| by radial vanes 31. Advantageously the X-ray transmitting windows 40 in the envelope I5, the cradle I6 and the housing I are disposed to be substantially parallel with the axis of rotation of the co-operating electrodes. Preferably the surface of the target is acutely inclined with respect to th-e tube axis through an angle approaching 90. Although the focal spot is attenuated by the angle at which the electron beam strikes the target so as to be relatively long in a radial direction, nevertheless it subtends a relatively small angle when viewed from the X-ray window to give the eect of a. focal spot small in all directions. The result is that the penumbra at the edges of the shadows cast by the X-ray beam will be small. y
Various changes may be made in the described apparatus Without departing from my invention.
device, a motor Within said housing arranged to Y rotate said device, and a generator located within vsaid housing and having a rotor mechanically connected to said motor and electrical connections for furnishing current from said generator to a cathode of said X-ray device.
2. An X-ray apparatus comprising the combination of a sealed housing, an X-ray device rotatably mounted therein having co-operating electrodes having respectively a cathode and target functions, a liquid insulating medium surrounding said device, a motor also contained within said housing mechanically connected to said X-ray device for rotation thereof, means contained in said housing for delecting from a normal path an electron dischargein said X-ray device whereby X-rays are generated from successive areas of said target electrode and an e1ectric generator also located in said housing and being Yoperatively disposed and connected to furnish current for heating the cathode of said X-ray device. l
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Great Britain Jan. 2l, 1932