US2482053A

US2482053A - Anode construction

Info

Publication number: US2482053A
Application number: US628304A
Authority: US
Inventors: Michael J Zunick
Original assignee: General Electric X Ray Corp
Current assignee: General Electric X Ray Corp
Priority date: 1945-11-13
Filing date: 1945-11-13
Publication date: 1949-09-13
Anticipated expiration: 1966-09-13
Also published as: FR937095A

Description

Sept., 13, 1949. M. J. zuNlcK ANODE CONSTRUCTION 'Filed Nov. 13, 1945 Patene Sept. 13, 194g NITE!) STATES 482,053 ANoDE CoNsTRUeaIoN Michael J. Zunick, Chicago, 111.,

a (non)gration of New Yor Application November 13, 1945, Serial No. 628,304 21 Claims, (Cl, V25.01-1519) The present invention relates in general to eleetmnies, emi hee hiere eetiielilei iefeifehee te ereys, .the intentie@ relating, iii. its eeeeiiie .eef beets, to .am imbreifeel .eleetiede eeitetiiia h becielly well etiitesi .fer ehti-bethedie ih geheietere S-.reys may be .generated by the imbi-tieemeht ei eieetreee, emitteii iiieih e eiiiteble 'eetiieiie einen en ehti-eetheele er eiieiie ieiihihe rey eene-fettine eehreef .Steh .eeetiei-.i imei eef ment been etereet eurieee .ef .the ehele .eretti .erewth .ih the .eheele materiel et Ahe tei-'eet eiiiieee diie t0 heet, liberated ih the eitetle ee e reeiilt ef electr-eh .liheeiheht theieti Stich emi-h erewth .resulte .in -siefeimetieh Splittine.. .ereebihe .ehe eiiilihs ef the ehede hieter.....1 et the target siii-.ieee ehe eeheeqiieht ieiiiie. eh ef ifrey output; thereby impeitihe the eberetiee Qi .the gehereter.-

Ah importent ebieet ef the preeeht ihveetieh .is to provide .eh -eheiie hei/,ine eh .impiaeifed tereet hiel-.ily .reeieteht t9 detei'ieretieh., .ih viee., lieder .the impact ef eleetreh iihPieeethee-t the-reen- .Ahether .importent ,ebieet te prpviie er;

prieihe ehede materiel ih eehee .eehi'iit'ieii .tieve ieg @articuler .eeeiLi-ieel .strutture enel eveneeehd ether ereeterietiee whereby 'the eiiedeis highly t-.teiieter-.ie .target eleieeihetieh .ehrliiie .er ereelihe- Ahether-.i beitelht ebieet ie te ferie e tete@ es e lemiheted betten rer Diete ethical-e :the ieihihetiehe eee Presented ,eiieeiifiee @were electhehe :ilhiiftieihe theieeh- Another important object is to ottllige egglage materiel f0.1' the htiiheee velf providing .eh .electhQh target., eheh hieteriel .eehiprieihe trie-.teil 11h eeihpleteiy heeiyetellized eehditiehs e itirther Obielet .beine te utilize materiel hei/.ine .ertiStell-ihe structure wherein the constituent :Ag-132.11115 @i the materiel ere ffiispesed ih Substantially .eeiellel reletiehehip, thereby r1er-'eeexiting ,eh fiend .efreih structure at the target surface to regcseivfe` electhehfimbiheemeht mathe-1' importent .ebieet is te bheffiete eh entitle .Comprising e teiseet .betten ei" iiilettfe mounted et the teheet eeiiyihgend i e .Stili eet member fof iron., .nickel .er Copper, the teteezet e.- teriel beine of :heet .resisting eharlateter. having e high mel-ting peint end ybeing mounted .Qn the seppeet .bese Whieh is pxeferabiy .ef weleer., :hei/.r ine high thermal conductivity; et fu'rztherebaeet being t0 .utilize target materiel subeteritielly pure zeehelitien ered t0 preteht ,eeepefee Qi 'the materiel 0i the Support member inte.. enel through ,the teifeet mehzlber, diieine ,the .eervice life .Q f the. aimee, by ,eeeiiiie the heels of the. laminated target member, Whieh is .seeuresi .te ,the 'supeert member. with .e @beting ef .materiel Siieh .es 'Pleti to .isolate 'the greih etuetiire ef the target niemeer trein the frieterei ,0i the Sublpert bese. The .foregoing .end numerous. ether .imperteht ebieete., eilvehteeesi mi inherent inhetierlis .ef the .ihyehtieh will beeome fully iiiiliereteee freie the iellewihe .deeeriptieh whieh, telseh .in eeh: heetieh with the eeeeihpehyi-,he drawing, elle.- .eleeee .preferred embeelimehte ei the ihiehtieh- Referring te the thawing-1 .Fie- .1 ie e. .eeetiehel' teken through .eze

.eeherelter titt'ed with en ehede'embeliyihe the present .intehtieies Fie.- .2 is enlarged .seetiehel eh anode of the type-.embedieel ih in Fig. 1;

Fig- .3 iS .e .ef vthe retery yention;

.Fiei is e Seetiehel ii-,leitf threiieh en ehede .ef the stetieneltf .ti/.lie `erhleeiiyiiie Athe prsent iii:- i/entieh-i Fie 5 .ie .e petepeetiye ieee ef e `.reeteheiiier leihiheted teieet bil-.tten eihbedyihe the' rteeehi lhvehtieiii Fig. G's a, perspective view of a target :disk .embeiiyiiie theeieeehtihvehteh: -7 is. .e eeetiehei Vietti heheh .eiibetehtieliy elpee the linee' iii-.1 ih -Fieef5, .ehe .eed `Fie- .is e eeetieeel Xie-,w ftetlseh thieueh eileetieted .ehethber in teieet `biitteiie conditioned for 1lpglstuxgttr1g ,emoties7 in eceordf ehee .with breeeht intention! Tile illiietrete the ihvehtien lthe drewihee shew en Xfiey eeiieieter .ill .eembrieiee e eeelee .eli- Yelebe t2 eehteihihe .eherie'eie i? ehe eetheeie ii ih ieeihe ieletiehehip With-iii :the ehteleee- The ,eethetie feihbeeii. .eh .eieetizeh z.ehiittihe .hier leent' iai -leliiiieeeeiitte .diizeeteleetieeefehiitted item .Seid .iileiheht -iieeh the .teeiee .iereet uhieee l ei thefeeeee ier-:the g.eerieretteteef ii-bays et ,Seid .eiiiieeeiiiteble reet-dii. 'ete ier eiteir eizihe the iilemeht' J5 e111@ ter .eefilyihe -eberetihe potentiel between the 'lment .and 1the mede View .threiieh .the eeheretbi Seettehel View through eh emile me 12, ehe etfihe eletti-.eet le? ,eeid temitietieeleetteie being impelled toward and caused to impinge upon the target surface under the inuence of operating electrical potential applied between the filament and the anode. The target surface may, as indicated in Figs. 1 and 2, be disposed in a plane normal to the path of electrons, or, as shown in Figs. 3 and 4, the target surface may be disposed at an inclination to such path, it being usual to dispose the target at an inclination in generators for producing X-ray for radiographic and diagnostic purposes. For other purposes, as in generators for X-ray diffraction analysis, the target is preferably disposed in a plane normal to the path of impinging electrons.

X-rays generated as a result of electron impingement on the target surface I6 may pass outwardly of the envelope, in a radial direction through one or more transmitting windows I1 formed in the envelope walls opposite the target end of the anode. If desired, the entire generator may be enclosed in a casing of X-ray opaque material, provided with an opening or openings forming X-ray transmitting window means opposite the window or windows I"I.

When the generator is in operation for the production of X-rays, a considerable amount of heat is developed at the target surface I6 as a result of electron impingement, such heat being dissipated through the body of the anode and thence outwardly of the envelope, the anode having an end extending outwardly of the envelope and provided, if desired, for the circulation of a cooling fluid through the anode which, in such case, may be hollow, or the outwardly extending anode portions may be provided with heat radiating fins for dissipation of heat to atmosphere outwardly of the envelope. The temperature at the target surface of the anode, however, may be of the order of the melting temperature of the target material, it being usual in the interests of operating efficiency, to operate the generator so that its anode, at the target surface thereof, functions at a temperature just short of the softening temperature of the anode material. When operated at such relatively high temperature there is a tendency for grain growth to occur in the anode material, such growth being evidenced by the peeling or curling of the anode material at the target surface, and consequent deformation of said surface from a desirable flat condition.

Various metals may be employed as electron targets, tungsten being commonly employed in diagnostic and radiographic generators, while copper and other metals may be used in generators for diffraction analysis. Certain of the novel features of the present invention have application regardless of the target material employed, and in this respect the invention is not necessarily limited to any particular target material and applies to inclined targets as well as targets that are disposed at right angles to the path of impinging electrons. A specic aspect of the invention, however, contemplates the utilization of platinum, columbium, tantalum, or molybdenum as target materials; and the invention, regardless of the target material employed, teaches a novel laminated target structure which, for optimum performance, comprises end grained material, and includes the structure and arrangement whereby the preferably high thermal conductive material of a support base structure is isolated and prevented from generating into and thus contaminating the material of the target element.

According to the present invention, the tendency of the target surface to curl and peel in service is minimized by forming the anode, more particularly at the target areas thereof, to provide dense, uniform and chemically pure metal, preferably having a grain structure characterized in that the grains of the material extend parallel with respect to each other and in the direction of electron impingement upon the surface thereof. In such end grain structure the individual grains of the target material, at the target surface I6, are presented endwise toward the electron source I5. Electrons impinging upon an end grained surface strike the ends of the crystals of material forming the anode target, such end grain structure, because of the compact, dense character of the material, tending to prevent peeling and splitting alonggrain boundaries.

The target material, also, is equiaxed, that is to say, the material is in completely recrystallized condition as by heating the same for one hour at a temperature of the order of 1600 C.

As shown in Figs. 2, 4, and 5, the target comprises a block I8 of the selected target material, the block comprising strips of material forming laminations I9. The material of each strip is transversely grained whereby the constituent grain crystals are in parallel relationship extending in a direction transversely of the strip to provide an end grain structure at and along the longer edges of the strips. The strips are arranged in side-by-side stacked relationship, as shown more particularly in Fig. 5 of the drawings to comprise the block I8. The strips are secured together in any suitable fashion, more particularly as hereinafter described; and the block I8 may be'mounted at the target end of the anode I3 as by forming a cavity 20 in said end and by securing the block I8 in the cavity, with an end grained block surface facing outwardly of the anode to provide the target surface I6.

As shown more particularly in Fig. 3 of the drawings, the target may comprise an annular member I8 formed by spirally winding upon itself a strip of preferably transversely equiaxed material, whereby the body of the member I8 may comprise side-by-side strip sections I9. The member I8' thus comprises an annular flat ring, the convolutions of its constituent spirally wound strip being secured together in any preferred fashion and more particularly as hereinafter described. The flat disk I8 may be mounted in an annular cavity 20 formed in the target end of the anode which, as shown, comprises an anode I3 of the rotating type, the member I8 being secured in the cavity 2D' in any suitable or preferred fashion.

The anodes I3 and I3 preferably comprise castings of any suitable material, such as copper, iron, nickel, and the like, copper being preferred because of its heat conducting characteristics; and the blocks I8 and I8 may be mounted by casting the supporting anode portions I3 andl I3 upon and around said blocks in a suitable casting mold.

In order to maintain the constituent material of the target blocks I8 and I8 in pure uncontaminated condition after the same have been mounted in the supporting members I3 and I3', it is preferable to apply a protective coating of material, such as platinum, as a thin layer 2I, at least upon the back end grained surfaces of the blocks I8 and I8', in order to prevent seepage, through such end grained surfaces, of the material of the support members I3 and I3.

The protective layer 2I may be applied by mounting the block IB orfl'mpon a :suitable 'support plate 22 within a `sealed compartment 2.3. This compartment may conveniently comprise a support 24 `and a removable, preferably glass, lbell jar 25 `inverted upon the support 24 and having edge sealing means 26 to seal the jarl 25 to the support to form the hermetic enclosure 23, which may be evacuated by a suitable connection preferablyy through the support 24 toan eX- haust pump. A button or wire of platinum may loey laid upon the surface of the member tobe coated within the enclosure 23 and melted in place to flowv upon and cover the surface to-be treated by the action of an induction heating coil 2l., which may encircle the jar 25 opposite the target block being coated. By melting the 'platinum button or Wire, the melted. platinum will flow upon and cover the end grained surface of the target member and may be allowed to harden in place.

Alternately, the layer 2| may-l be applied by vaporizing the metal and applying same, in vaporized condition to, and condensing it upon the surface to be coated; or the layer may be applied by spraying of sputtering the metal upon the surface, The surface also may be coated by electrodeposition in a suitable aqueous or fused plating bath.

After being coated, the target member may be mounted in position in theV anode by casting A the member I3, or I3', about the target button in a suitable casting mold. Alternately, as indicated in Figs. 2 and 4, the coated member I8, or I8', may be secured in the cavity 20, or 20', by

means of a suitable attaching alloy 28 interposed between the surfaces of the cavity 20, or 2U', and the cavity enclosed surfaces of the coated member I8, or i8', said attaching alloy forming a thin mounting layer integrating the target member with the anode base on which it is mounted.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from lthe spirit or scope of the invention, or sacrificing any of its attendant advantages, the forms herein disclosed being preferred embodiments for the purpose of demonstrating the invention.

The invention is hereby claimed as follows:

1. An electron target comprising a laminated block of target material presenting laminations edgewise to form a target surface.

2. An electron target comprising a laminated block of equiaxed target material presenting laminations edgewise to form a target surface.

3. An electron target comprising a laminated block of target material presenting end grained laminations edgewise to form a target surface.

4. An electron target comprising a laminated block of target material presenting the laminations edgewise to form a target surface, the material of the laminations comprising a metal selected from the class group consisting of platinum, columbium, tantalum, and molybdenum.

5. An electron target comprising a laminated block of target material presenting the laminations edgewise to form a target surface, the material of the laminations comprising equiaxed metal selected from the class group consisting of platinum, columbium, tantalum, and molybdenum.

6. An electron target comprising a laminated block of target material comprising a metal sele'cted 'froin the class group consisting cf platl num, columbium, tantalum, and molybdenum, the material ofsad block having a grain structure providing an end grained target surface.

7. An anode vfor an X-ray generator comprising a laminatedv block of target material pre-` senting laminations edgewise to form an electron target surface, said laminationsv having end grainedstructure at the electron receivingfedges thereof.

8. An anode for an X-ray generator comprising a laminated block of target materia-l selected from the group of metals consisting of platinum, columbium, tantalum, and molybdenum, said block presenting laminations edgewise to form anelec tron target surface,*said laminations `having end grained structure at the electron receivingv edges thereof. 'f'

9. An anode for an X-ray generator compris; ing a laminated block of targetmaterial presenting laminations edgewise toform an electron target surface and an oppositely facing mounting surface, a support base to which said mounting surface is secured, and a layer ofV protective material: covering said mounting surface in position interposed between said block and said base.

10. An anode for an X-ray generator comprising a block of target material forming a target surface and an oppositely facing mounting surface, said block having end grain structure at saidsurfaces, a support base to which said mounting surface is secured, and a layer of platinum coated on said mounting surface in position extending between said block and said base.

11. An X-ray generator embodying an anode comprising a laminated block of target material presenting laminations edgewise to form an electron target surface.

12. An X-ray generator embodying an anode comprising a laminated block of target material presenting laminations edgewise to form an electron target surface, said laminations having end grain structure at the electron receiving edges thereof.

13. An X-ray generator embodying an anode comprising a laminated block of target material presenting laminations edgewise to form a target surface, a support base on which said block is mounted in integral fashion, and a layer` of protective material coating a base attached surface of said block in position interposed between the base and the block.

14. An X-ray generator embodying an anode comprising a laminated block of metal presenting laminations edgewise to form a target surface, a support base on which said block is mounted in integral fashion, and a layer of platinum coating a base attached surface of said block in position interposed between the base and the block.

15. An X-ray generator embodying an anode comprising metal strip material disposed spirally to provide an annular laminated block of metal presenting the laminations thereof edgewise at the face of the block to form a target surface, a support base on which said block is mounted in integral fashion, and a layer of platinum coating a base attached surface of said block in position interposed between the base and the block, said strip material being equiaxed and having its constituent grain crystals in parallel relationship and extending transversely thereof to provide end grain structure at the target surface forming edge portions of said strip material.

16. An X-ray generator embodying an anode comprising metal strip material disposed' spirally to provide a annular laminated ilock of metal presenting the laminations thereof edgewise at the face of the block to form a target surface, a support base on which said block is mounted in integral fashion, and a protective layer of metal coating a base attached surface of said block in position interposed between the base and the block, said strip material providing end grain structure at the target surface forming edge portions thereof.

17. An anode comprising metal strip material disposed spirally to provide a laminated block presenting the laminations thereof edgewise to form a target surface at a face of the block, a support base on which said block is mounted in integral fashion, and a protective layer of metal coating a base attached surface of said block, said strip material providing end grain structure at the target surface forming edges thereof.

18. An electron target comprising metal strip material disposed spirally to provide a laminated block of metal presenting the laminations thereof edgewise to form a target surface at a face of the block, said strip material being equiaxed and having its constituent grain crystals in parallel relationship and extending transversely thereof to provide end grain structure at the target surface forming edge portions of said strip material.

19. An electron target comprising metal strip material disposed spirally to provide a laminated block of metal presenting the laminations thereof edgewise to form a target surface at a face of the zblock, said strip material providing end grain structure at the target surface forming edges thereof.

20. An electron target comprising metal strip material forming a laminated block having laminations providing edges disposed in a common plane to form a target surface, said strip material -being equiaxed and having constituent grain crystals in parallel relationship and extending transversely thereof to provide end grain structure at the target surface forming edges of said strip material.

21. An electron target comprising metal strip material forming a laminated block having laminations providing edges disposed in a common plane to form a target surface, said strip material providing end grain structure at the target surface forming edges thereof.

MICHAEL J. ZUNICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,214,500 Bates Feb. 6, 1917 2,332,422 Zunick Oct. 19, 1943 2,379,397 Zunick June 26, 1945 2,399,752 McCullough May 7, 1946