CA2360409A1 - High energy x-ray tube - Google Patents

Abstract

A high energy X-ray tube has a cold cathode and anode in opposed relationship for the electron emission X-rays formed by the electron beam to travel directly to the cathode to produce further electron emission. The electron beam is collimated to be concentrated in a spot size on the anode with the result that the resulting X-rays are emitted at 180~ to the direction in which the electrons are emitted. A Pierce-type electron gun design is used for the collimation.

Description

From: HEATHER EDWARDS - MORRISON FORSTER INC. at 0315023818 To: - Sent at:
13107/01 12:41 Page 28 of 33 L3/07 'O1 FRI 13:19 FAX 031 5023819 MORRISON FORSTER
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~~ ~Y X-SAY TG's , ' T~~ .D OF T~ 111TVE1VTIO~hT , 'I , . I
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' i , ' ~ ~ i 'Ilie oonvx_~y ~e 8 ahiah is at ~ aa~, Dp the e,~' ~ Y , y , emitted 8~m the ca;$rode aad thr ~ 'o~ a ~~ ~ deter ,yy a detoGtor locxbod is ~C ~ ofd t~ec4~cL t~tc,~y , ~ ~ , .. ., r, about 9~ ~~t~ b~ave~s that the e~,~y pf tle~L~ could be ,~ ~' ' ~ .
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It is as objedt of ~e pt~reC~t boar to ' ~- ' ~'°"~'° a x-i~.y;b~be w~ r does mot roquarrs sv~ ~ vacta>nm arnd which i6 fgr o~ eg~~t than cvnv~eotial»1 t~ ..
In thacray 9~ ~e ~ y l~t~d. ~n ~ r y 1 ~ . ' '.
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~~ ~~7 t'~ d ~~ , i W a x-ray tube ~w3qg z ~3Z imi , f~roe-to-face xt~ w3~ a first dynode 40; a seaeod ,dynode 4~ ~g laic wirh ~ , sad saxide the cat~od~ 8lecho~s the i~tst ooods- ~~ to tho n electron mall ~ ~ end aide at~d the ~ ' ~cele~aood m au made 3g fi~ r ~ n I , r are metl ~ i which thry egg >ahewie by ~neft~~aoe 48. to ttte ~~ y~rr~tion thorle ;9 ~' art rather' aretora afrhe be~a m xhe eatbods Tns !lathes el~na emiss~~ .
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AMENDED SHEET ~ ' .
EMPFANGSZEIT 77. FfR_ 13.x! ancnoutYC~c~r'~" rro ~,~s.~., From: HEATHER EDWARDS-MORRISON FORSTER INC. at0315023E19 To: - Sent at:
13/07!01 12:41 Pa a 30 of33 13/07 'O1 FRI 13:20 FAX 031 5023819 MORRISON FORSTER .030 GES.VON:FPA dJUNCI~i~N O1 ;28- 5- 1 ~ 9:54 ; t49 89 23994560 081 5423818; 7110 _.,r. ~.. _ ",, s"s vaw autantu xp~gpp g. .: _ . _"_..... ._ ' ~ aoooooaio 2'~ yb2-Zoo 1 ., ~ I .
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..", ~Cary describes a x~r tube fa arbalch tbte a~oda r3 is cued s6 . ' that the x-ray beam ~ the cathode is not oolli:touDod as it is is the psoscut iuvavl3~: The , noodle Z~ is oat a Pierco-typc electrode. A Piaea--type olcc~tcvdo~ is a ring ele~mrl~ that fog ereetra~c~sto pmdooe a cylindrical elf beam shape. Thva, the Pierce-type n , .
erode psa spot size as app~od tt1 the m sips of the beam of Iv~CG~r. ~ . ' ~p 60 O~73,SS 'fbls d~rlbes an erraoge:mee~t iri whtda rays arc rah fi~a the esrtire cutter a,,~;fa~e of t~ ca~atl~er body f4r n~rmn sbdiatton. 'this is vixutally the - ' i c~posite ~ ha~ri~g regard to the ~escxtt irwanttau ~ xs its objeei, a col~n~ø~
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. : . . ~ i l .~aoatdiag tc the fiver a high ~r x-ray tai oomp~d~g a cold a sari as sm~ode ~aeat~d in oypasod rehrtio~htp , cbatacbr3~ed. in tt»t tba dad beam is . .
~Vimated v~ith thr aaslomnCC of s 'type pls:rac ~g~ a~ud .eonal:cd: is prrd.cuQar spot siu flf t1~ ~dt~ed ~ca~r beam an the anodo so drat ttuo ring a.~ys spy ~' , , ~ , e~lsad at I80 de~roes bo t>x dixxtion tri vrhiah the elealnons a>1c aaoifted, th~a cathode ~r~ufn~tg a sviodn~ for traeemiasioxt~ of the rays p~t9d~d. ' ' ' ' . ' The oledtntl beats ns ptef~ly collimated ao tlast it fis off, j~ i~ a -.I
prodctomwo~ed path, ~o~ exra>upie in a pard~r apvtsize of flu pr~iducod X tax bcaan on the au~ade; t'ho reau~6hsg x-says bail tlxxeby Ntritteed ~tt J,BIY tv t$e darrctioo ;tn w~ch tho ale~eo~s arc emitDa~d. , . ~ ~ a ,y ~ y , , .
. f , r In a for,n of the inveatioa the ooliimatioa is acviavad by rn,.asas of a Piece-type eleohoa:gma de~,,ga, Whoa deal~og ldgb d~ a rpaee cba~e , e~ is estahad; Which w~ili del~ct from the e~ay Qf the 'x~ay tube of the ptesrt~t v a which ral~iea ~ the paod»n of an elec~nn ~Hovr e$'ect s~ as true sue ~autia +i w y . .
an idealised dodo, , Pi~Ce~s tlaray of acorn beam desiga yes the tne~o~ of a t~itpat~ial decode, called the beam g ox ~uaing eleattnde wrhioh ~fielda ~ , outside the eleetmn bce<n to be fonmoed to ssttaty the propor boar aoridi~olas is aver ' I

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- AMENDED SHEET ~.' ' EMPFAN6SZEIT ?7. F~9. 1 ~:5~ AiiQllN(I~YQ'7trt e~ crn a w.. n., From: HEATHER EDWARDS- MORRISON FORSTER INC. at 03150231119 To: -Sent at: 13107/01 12:42 Page 31 of 33 oai 13iO7 ~01 FRI 13:20 FAX 031 5023819 MORRISON FORSTER ti/ 1 ; 28- ~- 1 ; 9: 54 ; t49 89 23994560- U31 SU1361~ ; ~ U

GES. VON FPA MiJNCHEN UJ.
rua iy.ai rna o.sa, vvs~ai.a ~J~tltl~Vlr irVli~Ihl~ , zA ooaooooi o a7-8a-2ooi , , r mr , -3- ~

_ ,.,.r wards the deWl behavle as tough tbep wrens 8oan"~ ~n a oo2np~e, t3iade . that ~s, ~

they p~naur~ eecftiinaac tse~ed~3a. .
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As fir as the Applic~x~t is ~a~c, sod ~. ~e~n ~ ~~ b>~s nar ba;a , ' ta;ad is ~Crx~ty tu~xs,. aor is eo~f uactio~o wilt a ooid e:~Cde. 1 .
A ~ncB~r discus~aet of t1>tds asspeat of the en~on will be ~umd i~a the do~ption of ttte elm'b~idiof, ;
~e invrntioon below. ' .f' ,'I
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In a ~ue~ed Sorm o~thc inv~tion the cathode includes vv~n~dovv fbr tret~xnid'ion of the x =sys ~oaod~d- , , , , . . I

oc! ae~oau~ the va~nun yr arrvass~ 1 ' ~' The ~eo~e~ 4f tbC t~la f! ~re~ to p~t~t ~d~$ , the ~aial of thr t>vbo arld the eLe~odas, and at the acme terra tv nd$ovo opt'h~

focusing of the amEi~ epos So tbat they Colt st~Ce the 9aodp sarfaCe I
fat a ~t anghe ,~

aad lve~ x~ m~r~ ~t~a~aity is arinntabed et 180 to t'he dvc~ria 1 .

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. . , , Tb,~ ca~Ode msy be ,a cold pblOioc~thode mach fi~a ola~th allcs,~l , ~ .
o7d~ on a os ~eocemplo N- based Mg0 dut goo ~tc pct that a self-s~uod olo~n. ~ , .
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matatlic base , Y
eOn $CIDSt! Cold ~Oud>s $lmt l~lpllt~ to t slCC~fC or mesh cap bC

a~'~ bY iPPlY''~ a m~ur of 308V to the anod>w A pos~vta ~ 99 devdopod oa tbe, magaesium layer p~nduc~ag a hi~gb eteotricnl field of the cslder' ' , of 541~V'Ic~a, ride $e layer. BIeC~O~ Which tus 1bctated in t'L~e ~itm>< oxide o0at~g auc xlatiltilpliod by F
ea S1G fi0 $~ t0 leave th:0 S1~C~ ~ C~lBatt~

eaa be conttoilcd by v~sy~81~ volta~ oftho anode aaullar of tlwriag da~d~ sQ that c>tareoata of att~a~al ~baoovs vi' >~icaan be ad~iov~ed ova o ~Ciod ' of ac~rai tlLOOSSOd ivoura hut any ~9axcasse fn aoaiaeaon. ~ , ' , , >

, v T9>cati~ may a thin aad pomua a~ ~odc isye~Whiah 5s ' appl~od to tha nic~l met. , I

.~ , , The tube may be of,idined c~iC aad. mental oar g181ss and Imecal. , . . i .

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AMENDED SHEET ' t EMPFANBS7F (T. ?7., FFR 1~ ~~ aucnallrrc~crT ~~ cc~ , . ~, .

From:HEATHEREDWARDS-MORRISONFORSTERINC.at0315023819 To:_-_ Sentmt:13/07/0112:42 Page32of33 13/07 'O1 FRI 13:20 FAX 031 5023819 MORRISON FORSTER _ 1032 Gds. vON : ~A MUn~CHEN o 1 28- s- i ; 9: 55 ; t48 89 23894s80-~ .l 031 5Q2a~i 9 ; ~ 9l i o ie,r~ i"..ra rnr Boa ev~ao.r.v. aaraaaiovn rvaatrw ' 2~'-02-201 , ., "~ ~ , ~ ~ , ,.
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A~ ~t crF tb~e i~nuiom is daaibed b~e7.ovu wi>H~ ~ ~ ~
accor~g r~ca~jrl~, xn', , . .
Figure I is a sx~tio~1 aido ~ule~r of ~ 3C.'raya y tube act ~po the i~w~,>~~;
F~guee 2 iss disgramlmatio ,~p~,on of a ~'ie~etype Pte, ~dectrlo,o, gtt,~ ~~
ada~d ~os n9c ~~t the 7~~'a~r tube of t3u iuveation;
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Figure 3 i» ;a of ~ aqoipobaorhal lip ~tp , $e Flaw sp~e limited electron j~ at ,ding di~taucas 8vam the exige of tha beam sad fsnm e~
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Iu F'igore l a aermmie sleeve l~ dicJosenc ata aop~ 1~ ~,nd a epode iu~, by ~re~ecaoe~ 14. A f6~tng leoe ifr ~Or the 7C~~yrs omitted by 1~ ~e 1Ls ioa~
above the , catbnda ~1 X ri1y wiadow ~0 end a ode g~ ~ ' z4y w s~ ?2 are aiso ,plcruwicied at th~ 6aso of the tube. The cetbode is ado $~n a~ eat oxides on >~ ' f ~ ' ' met bass s~ceh ws m~p~i~ oxide oa a aic'kd bast. Tha auvde may beJV~-~,~ a>ad is . , parsliul with tile cathode. - .
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~ 8~1. the o4n of tlse tube mli~ oa the esaeblisbmeot of m doct~l pa~ 't' , , t , ~ I
Whim ~ t~ erode at right mt~es. t~ozao of t'bc ~ ~ peas ih~oa~h t~ 34 fax ao~yaes Wbilo those Shat dt~ ~aot pass ~vug~ t~ stdJ~e the eats ~ ' ' ~n'ihar el~ma ur be e~ntttod ~ , . , t ~. ~ . .
As indict abny~e'a Pieecatxpe ela~o~ gin ~ ia.provlded aud, dig xs illttstramed in Fi~,e~'~ wix~ne the ~tlxOde 38 fs s,~ ~ a d82 ~~
mm~ bao~lc to it~e desired ded~lnpath betweaa e~h~ and c~pde 34. ~ r ., r. , , ;
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EMPFANGS7F1T 77FFR .5~~~,1~ Ailrnpyrrrc~ctr ~, rrn ' " ", ~ '

Claims (5)

CLAIMS:

1. A high energy x-ray tube comprising a cold cathode and an anode located in opposed relationship, characterised in that the electron beam is collimated with the assistance of a Pierce-type planar electron gun and concentrated in particular spot size of the produced x-ray beam on the anode so that the resulting x-rays are emitted at 180 degrees to the direction in which the electrons are emitted, such x-rays causing further electron emission from the cold cathode significantly to contribute to the operation of the x-ray source, the cathode including a window for transmission of the x-rays produced.

2. The x-ray tube according to any of the above claims characterised in that the geometry of the tube is arranged to prevent arcing across the vacuum or across the material of the tube and the electrodes, and at the same time to achieve optimum focusing of the emitted electrons so that they can strike the anode surface at a right angle and hence produce x-rays orientated at 180À to the electron beam.

3. The x-ray tube according to any of the above claims characterised in that the cathode is a cold photo cathode made from a metal-based alkaline with oxide.

4. The x-ray tube according to claim 3 characterised in that the cathode comprises a thin and porous magnesium oxide layer applied to a nickel mesh.

5. The x-ray tube according to any of the above claims characterised in that the tube is of joined ceramic and metal or glass and metal.