Iipayipi ze-X-ray zisebenza njani?

-X ray eyenziwe ngokuguqula amandla electron ukuba photon, kwenzeka ityhubhu X-ray. Ubungakanani (exposure) kunye (spectrum) radiation umgangatho anokuthi alungi-lungiswe ngokuguqula lwangoku, ombane kunye nexesha isixhobo.

isimiso ukusebenza

ngemibhobho X-reyi (ifoto enikwe kweli nqaku) ezi converters amandla. Baya andizamkelanga womnatha baza basenza nezinye iintlobo - luchukumisa radiation nobushushu, eyesibini i eceleni ezingathandekiyo. X-reyi isixhobo tube ezinjalo ukuba nkulu ukuveliswa photons kwaye uyakhululeka ubushushu ngokukhawuleza kangangoko kunokwenzeka.

Ithumbu isixhobo elula, ngokokuqhelekileyo oquka izinto ezimbini ezingundoqo - a cathode kunye anode. Xa ngoku aqukuqela ukusuka cathode ukuya anode, electron alahlekane namandla, nto leyo ekhokelela ekubeni isizukulwana ka-X-reyi.

anode

Le anode yinxalenye, apho ukukhutshwa ziluhlaza ophezulu ugesi. Le yinkalo metal elikhulu kakhulu oludityaniswe kwipali ezakhayo yombane. It inemisebenzi ezimbini eziphambili:

• Itshintsha amandla electron ibe radiation X-ray,
• Uyakhululeka ubushushu.

Izinto kuba anode ikhethiwe ukwandisa le misebenzi.

Ngokufanelekileyo, inkoliso elektroni kufuneka ibe ziluhlaza eliphezulu-amandla, kunokuba ubushushu. Ratio yamandla zizonke, nto leyo iguqulelwa kwi X-radiation (COP) lixhomekeke kwizinto ezimbini:

• ulawulo lonyanzeliso (Z) yesixhobo anode,
• electron amandla.

Kuninzi ngemibhobho x-reyi njenge ebambekayo anode esetyenzisiweyo Tungsten, onombolo yakhe atom ilingana 74. Ukongeza Z elikhulu, olu uye ezinye iimpawu ezithile ezenza kube efanelekileyo ukulungiselela le njongo. Tungsten iyodwa ngamandla ayo ukugcina amandla xa itshiswa, kukho indawo yokunyibilika eliphezulu kwaye izinga uwase eliphantsi.

Iminyaka emininzi, le anode yenziwe Tungsten ecocekileyo. Kwiminyaka yakutshanje, siye saqala ukusebenzisa le intsila yentsimbi oluLula, kodwa kuphela phezu komhlaba. Self anode phantsi ukutyabeka Tungsten-oluLula ezenziwe ngezinto ukukhanya, elungileyo ubushushu-USB. izinto ezinjalo ezimbini molybdenum kunye mifanekiso.

Ityhubhu X-ray ingasetyenziswa xa mammography, wenziwa anode, isale molybdenum. Le nto iye inani eliphakathi-atom (Z = 42), nto leyo yenza ziluhlaza amandla kweempawu ezifanelekileyo ukuze ubhale esifubeni. Ezinye izixhobo mammography kwakhona abe anode yesibini, wabumba ukusuka rhodium (Z = 45). Oku kwenza kube lula ukwandisa amandla ukuphumeza umthondo omkhulu ngenxa yamabele ashinyeneyo.

Ukusetyenziswa Tungsten-oluLula ingxubevange kuphucula imveliso radiation ixesha elide - izixhobo ixesha ngendlela kunye anode ezenziwe Tungsten ecocekileyo lifinyele ngenxa umonakalo thermal ngaphezulu.

Uninzi anode unalo imilo IiCD tapered, wayifaka kwizikhondo motor, yokubolekisana kubo ngesantya eliphezulu ngexesha ukukhutshwa-X-reyi. Injongo yale ukujikeleza - ukususwa ubushushu.

indawo focal

I-X-ray isizukulwana inxalenye hayi lonke anode. Oku kwenzeka kwindawo encinane kumphezulu wayo - le ndawo focal. Imilinganiselo yokugqibela kumiselwa ubungakanani electron umqadi evela cathode. i imilo engunxantathu Xa uninzi iye yahluka ngaphakathi 0.1-2 izixhobo mm.

I-x-reyi uyilo ityhubhu kunye nobukhulu ethile le ndawo focal. I ezincinane ke, incinci eshukumayo kweso kunye kabukhali ephezulu, kwaye ngaphezu koko, ngcono ubushushu ukusasaza.

ubukhulu indawo Focal ngumba ekufuneka iqwalaselwe xa ukhetha ityhubhu X-ray. Abavelisi ukuvelisa izixhobo kunye indawo ezincinane focal, apho kuyimfuneko ukuba kufikelelwe inkjet nemitha ezincinane ngokwaneleyo. Ngokomzekelo, kufuneka kuwo nasekufundweni namalungu amancinane kunye ubuncwane omzimba njengoko mammography.

Ityhubhu X-ray ikakhulu ukuvelisa iindawo bamalungelo ezesini kunye nobukhulu ezimbini - ezinkulu nezincinane, nto leyo kungaba ukhethe umqhubi ngokungqinelana umfanekiso inkqubo bokwakha.

cathode

Lo msebenzi ungundoqo cathode - ukwenza electron nokuqokelela libe umqadi mayibhekiswe anode. Ngokuqhelekileyo iquka ucingo encinane uwele (filament) elungiselwe elitywinwe indebe-ezimile.

Elektroni edlula wesekethe akakwazi ngokuqhelekileyo ukushiya umqhubi kwaye ushiye isithuba free. Noko ke, abanako ukuyenza loo nto, ukuba sibe namandla ngokwaneleyo. Xa inkqubo eyaziwa ngokuba amadlozi thermal, ubushushu kusetyenziswa ukuze amgxothe electron ukusuka cathode. Oku kwenzeka xa lo xi an x-reyi ityhubhu bakhutshwe ifikelela 10 ^-6 -10 ^-7 Torr. Art. Le ntambo itshiswe ngendlela efanayo njenge uwele filament isibane ngokugqithisa a therethrough yangoku. Umsebenzi cathode ray ityhubhu sikhatshwa ngokufudumeza ukuya lobushushu chweba ukubana amandla thermal lulo electron.

ibhaloni

Le anode kunye cathode laliwaphethe izindlu evaliweyo - cylinder. Ibhaluni kunye nemixholo yawo kudla ngokubizwa ngokuba sisihlomelo, nto leyo eye ubomi eliqingqiweyo yaye kutshintshwa. Ityhubhu x-reyi jikelele ibhalbhu iglasi, nangona intsimbi kunye yodongwe iisilinda esetyenziselwa ezinye izicelo.

Umsebenzi ophambili kukuba ukuxhasa isiqulathi kunye bodwa le anode kunye cathode, kunye cleaner nokugcina. Uxinzelelo kule x-reyi ityhubhu bakhutshwe kwi-15 ° C 1.2 × 10 ^-3 Pa. Ubukho igesi etankini kuya kuvumela yombane ngokusebenzisa isixhobo ngokukhululekileyo, hayi nje ngohlobo kukho umqadi electron.

izindlu

X-reyi ityhubhu izixhobo ezifana ukuba, ukongeza yentendelezo kunye nenkxaso kwamanye amacandelo, kuba ukhonza umzimba amakhaka lubamba radiation, ngaphandle umqadi luncedo edlula i window. kumphezulu wayo elikhulu yangaphandle uyakhululeka uninzi ubushushu eyenziwe kwisixhobo. Isithuba phakathi iqokobhe kunye yofako igcwele ioli olunika yokwambathisa apholisayo ngayo.

chain

Le yombane inxulumanisa ifowuni umthombo wamandla, ekuthiwa generator. Umthombo kuxhaswa kuthungelwano kwaye luguqula le ifildi yangoku ukwalathisa lwangoku. Nale generator kwakhona ikuvumela ukunyenyisa ezinye Ipharamitha chain:

• KV - ombane okanye lobungakanani bombane;
• MA - okhoyo ujikeleze lonke ityhubhu;
• S - ixesha okanye ukungakhuseleki xesha, xa amaqhezu yesibini.

Umphathi wesekethe inika intshukumo electron. ukuba babekwe amandla, acandacanda wenkunkuma, niyinike ukuya anode. Njengoko intshukumo yabo kwenzeka zinguquko ezimbini:

• amandla ombane okunokwenzeka iguqulelwa kwi kumandla entshukumo;
• entshukumo, ke, iguqulelwa kwi X-reyi kwemitha kunye nobushushu.

ezinokubakho

Xa electron zifika kwi iselwa, bakuzuze amandla amandla ombane, nto leyo kumiselwa isixa KV ombane phakathi anode kunye cathode. Ityhubhu X-ray wenziwa utyando kwi ombane ukwenza 1 KV apho yamasuntswana nganye kufuneka 1 keV. Ngokulungisa KV, umqhubi unika electron ngasinye umlinganiselo othile wamandla.

kinetics

uxinzelelo Low ngendlela x-reyi tube bakhutshwe (kwi-15 ° C kungenxa 10 ^-6 -10 ^-7 Torr. V.) Ivumela amasuntswana phantsi inyathelo ukukhutshwa nangamandla thermionic zombane ezikhutshiweyo kula cathode ukuya anode. Le mandla ibalekisa kubo, kubangele isantya eyonyukileyo kunye namandla entshukumo ukwehla ezinokubakho. Xa yamasuntswana emazweni phezu anode, amandla yayo ilahlekile, yaye onke amandla alo iguqulelwa kwi kumandla entshukumo. keV-100 electron ufikelela kwisantya ngaphezu kwesiqingatha isantya ukukhanya. Imbetha phezu kwisuntswana kuyehla ngokukhawuleza kakhulu kwaye balahlekelwe amandla entshukumo. Uvula kwi-X-reyi okanye ubushushu.

Elektroni ezidibana kunye atom ngabanye izinto anode. Imitha eyenziwe intsebenziswano yazo orbitals (X-reyi photons), yaye ezininzi ezinombindi wesiseko (bremsstrahlung).

amandla nganisa

electron ngamnye i-atom kukho amandla athile esibophelelayo, nto leyo kuxhomekeke kubukhulu yokugqibela kunye kwinqanaba apho iqhele kwisuntswana. Amandla iyabophelela lidlala indima ebalulekileyo isizukulwana uphawu X-reyi kwaye efunekayo ukususa ovela evela atom.

bremsstrahlung

Bremsstrahlung uvelisa elona nani likhulu ziluhlaza. Electron ukungena kulo mbandela anode kunye nokwandisa kufutshane ngumongo, baphambukile yaye yehla yaya omxhuzulane amandla atom. amandla abo ezilahlekileyo ngexesha le ntlanganiso kubonakala ngohlobo X-ray photon.

ezahlukene

Kuphela nje ziluhlaza ezimbalwa kuba amandla kufutshane amandla electron. Uninzi kubo usezantsi. Bacinga ukuba kukho isithuba okanye umhlaba ongqonge undoqo, apho electron amava amandla "inhibition." Le intsimi lungahlulwa-hlulwa zibe imimandla. Oku kunika imbono ongundoqo entsimini atom ekujoliswe kulo kweli ziko. Electronic falling naphi na kwi thagethi yehla yaya kwaye yenza i photon X-ray. Amasuntswana eziwela ikufutshane kweli ziko, abakhuselekanga kakhulu kwaye ngoko ulahlekelwe amandla amaninzi, ovelisa kakhulu ziluhlaza esinika amandla. Elektroni engena kummandla ongaphandle ezinengxaki ngonxibelelwano buthathaka kwaye ziveze ziluhlaza zamandla elisezantsi. Nangona ndawo babe ububanzi efanayo, ukuba indawo eyahlukileyo ngokuxhomekeke kumgama ukusuka ngumongo. Ekubeni inani amasuntswana ngesiganeko ummandla, kuxhomekeka kwindawo ogcweleyo, kucacile ukuba indawo yangaphandle zifake electron ngakumbi zibangele ziluhlaza ngaphezulu. amandla X-ray spectrum linakho ukuqikelelwa yi kule modeli.

E ziluhlaza _max engundoqo bremsstrahlung spectrum olungqamana E electron _max. Ngezantsi le ngongoma, kunye ngokunciphisa amandla photon kwandisa inani labo.

Inani elikhulu ziluhlaza amandla ophantsi wendele okanye ecociweyo, njengoko kuzama kugqitha phezu ityhubhu anode okanye ibhokisi lokucoca ulwelo. Yokuhluza kuxhomekeke ngokubanzi malunga nokuqulunqwa kunye Ebubanzini izinto ngalo umqadi passes, yaye oku kugqiba fomu lokugqibela ephantsi amandla omoya curve.

impembelelo KV

I eliphezulu-eneji yinxalenye uluhlu limisela ukuba ombane x-reyi iityhubhu e kV (kilovolt). Oku kuba kugqiba amandla elektroni yokufikelela anode, kunye photons nga akufunekanga olukhulu kunolu. Phantsi na ombane ibaleka X-ray tube? Amandla photon iphezulu elivumelana ubuninzi isicelo isakhono. Le ombane ingahluka ngexesha sesichengeni ngenxa zothungelwano ifildi yangoku. Kulo mzekelo, E _max ombane peak ezimiselwe photon oscillation ixesha KV _p.

ufaka Further ezinokwenzeka, KV _p kugqiba ubungakanani radiation eveliswe banikwe inani elektroni okufika anode. Ekubeni ukusebenza lilonke radiation bremsstrahlung linyuke ukunyuka amandla ngesiganeko electron, efunyaniswa KV _p, oku kuthetha ukuba KV _p kuchaphazela ukusebenza kwefowuni.

Ukutshintsha KV _p, ngokuqhelekileyo ukutshintsha zazo. Le ndawo iyonke phantsi amandla igophe imele inani ziluhlaza. spectrum engacocwanga yi unxantathu, kwaye isixa radiation ngokomlinganiselo isikwere KV. Phambi lokucoca kwandisa KV Ukwanda kwii-photon, kunciphisa ipesenti kwimitha yahluzwa. Oku kukhokelela ekwandeni isivuno radiation.

radiation uphawu

Uhlobo ukuxhumana olwakha radiation iimpawu yenziwa-high speed zicinywe electron Orbital. Intsebenziswano lweziBhalo lunokubakho kuphela xa inxalenye E _kwisuntswana esikhulu ngaphezu amandla nomphetho i atom. Xa le meko yadibana, kwaye kukho kungquzulwano, kuba electron yeni. Oku kushiya indawo evulekileyo, esizaliswe kwisuntswana inqanaba eliphezulu amandla. Njengoko sisiya electron unika amandla ukhutshiwe ngohlobo X-ray photon. Ibizwa ngokuba yi-radiation iimpawu, ekubeni E ke photon luphawu yemichiza element le anode lwenziwe kuyo. Ngokomzekelo, xa electron kukho umntu oligilileyo K Tungsten _uqhagamshelo layer kunye E = 69,5 keV, isithuba izaliswe ovela ukusuka _{unxibelelwano} L-level kunye E = 10.2 keV. Uphawu X-ray photon anamandla elingana umahluko phakathi kwamanqanaba amabini, okanye 59,3 keV.

Enyanisweni, izinto anode kukhokelela kwiqela amandla X-ray isici. Oku kwenzeka ngenxa yokuba elektroni kumanqanaba ngamanqanaba eneji (K, L, njl) unako ligilwe bombarding amasuntswana kwaye izithuba nizaliswe ezahlukeneyo kumanqanaba amandla. Ngoxa izithuba L-level yenza photons nangamandla zabo zincinci kakhulu ukuba zisetyenziswe imaging diagnostic. eneji ngasinye uphawu unikwa unyulo leyo ibonisa Orbital, apho isithuba, kunye isalathisi ebonisa kumthombo electron efunekayo. alpha (α) kubonisa kwisalathiso electron yokuzalisa ukusuka L-level, beta (β) ibonisa inqanaba ukuzaliswa M okanye N.

• Spectrum Tungsten. Yemisebe uphawu intsimbi lenza spectrum yomgama eliquka amandla eliqela obubobu kunye elekhtrons yakha nokwabiwa oluqhubekayo. Inani ziluhlaza okudalwe amandla ngamnye uphawu, ungachazwa ukuba amathuba yokuzalisa zezithuba K-level kuxhomekeke Orbital.
• Spectrum molybdenum. Anodes yalo zentsimbi esetyenziselwa mammography, ukuvelisa ezimbini ngokwaneleyo olukhulu iimpawu x-reyi energy: K-alpha kwi 17.9 keV kunye K-beta kwi 19.5 keV. Uluhlu ngokupheleleyo kweetyhubhu X-reyi yesifuba, nto leyo evumela ukufikelela ukulingana ilungileyo phakathi uthelekiso kunye nedosi zokukhanya ukuba isayizi ibele avareji abafundi E _p = 20 keV. Kodwa Bremsstrahlung amandla ngaphezulu. Xa izixhobo mammography ngenxa yokubulala iindawo engamkelekanga malumga esetyenziswayo molybdenum lokucoca ulwelo. Isihluzo isebenza kumgaqo «K-buthelezi." It imisebe in electron kwemfuneko yokubopha amandla kwi K-level molybdenum atom.
• LwaseNtshona Koloni ziba rhodium. Rhodium unenani atom-45, yaye molybdenum - 42. Ngoko ke, lo uphawu X-ray ye anode rhodium kuya kuba amandla aphezulu kancinane kunalowo molybdenum kunye gaze ngakumbi. Isetyenziswa iMifanekiso amabele ashinyeneyo.

Anodes neendawo kabini umphezulu, molybdenum, rhodium, ukuba umqhubi ukuba ukhethe unikezelo olulungiselelwe amabele ubungakanani ezahlukeneyo kunye mninzi.

Ifuthe kwi KV spectrum

ixabiso KV luchaphazela kakhulu yemisebe kuphawu, okt. K. Ayisayi kuveliswa ukuba ngaphantsi KV level K-amandla electron. Xa KV sidlula eli xabiso threshold, isixa wemitha umlinganiselo jikelele ukuba umahluko umbundu KV tube KV.

I-eneji spectrum photons of beam X-ray ophuma ifowuni kumiselwa izinto ezininzi. Ngokuqhelekileyo, oko ibandakanya bremsstrahlung kunye nobudlelwane isici.

Ukubunjwa isihlobo spectrum kuxhomekeke umbandela anode, KV kunye filter. Xa tube kunye Tungsten anode amadlozi Uphawu akukho luyasekwa KV <69,5 keV. Xa amaxabiso aphezulu HF ezisetyenziswa kwizifundo diagnostic, radiation uphawu kwandisa radiation iyonke kwi-25%. Zizixhobo molybdenum ukuze ukufikelela inxalenye enkulu itotali omlinganiselo.

ukusebenza

Kuphela inxalenye encinane amandla kusiwa yi electron iguqulelwa radiation. Iqhezu ephambili ako kwaye aguqulwa abe bubushushu. ngendlela radiation uchazwa iqhezu iyonke yemisebe amandla avela ngogesi jikelele wafundisa anode. Imiba leyo iza kucacisa ukusebenza kwe ityhubhu X-ray zisetyenziswe KV ombane kunye atomic Inombolo Z. Umlinganiselo omalunga oku kulandelayo:

• Bongeka = KV x Z x 10 ^-6.

Ubudlelwane phakathi ukusebenza KV kunempembelelo ethile ekusebenziseni esebenzayo izixhobo X-ray. Ngenxa isizukulwana ubushushu ityhubhu abe umda kwinani kwamandla ombane ukuba zimke. Hlobo azibeka umthamo komda ifowuni. Noko ke, ngokungathintithiyo KV, ubungakanani radiation oluveliswa omnye ubushushu kwandisa kakhulu.

Ukuxhomekeka of ukusebenza isizukulwana X-ray malunga nokuqulunqwa kwenqaku le anode kuphela umdla kwizifundo ngenxa yokuba izixhobo ezininzi ezisetyenziswayo Tungsten. An Okungumahluko molybdenum kunye rhodium, kusetyenziswa mammogram. Ukusebenza kwezi zixhobo usezantsi kakhulu ukuba Tungsten ngenxa inani labo esezantsi atomic.

ukusebenza

Efficiency X-ray ityhubhu uchazwa isixa zokukhanya millirentgenah zisiwe yencopho embindini umqadi luncedo kumgama 1 m ukusuka ndawo zingumgqaliso nganye 1 Mas electron ecanda ifowuni. ixabiso layo imele nokubanako isixhobo ukuguqula amandla amasuntswana amacala radiation X-ray. It ikuvumela ukugqiba ukungakhuseleki kwisigulana, kunye okhawulezayo. Njengoko ukusebenza, ukusebenza ifowuni kuxhomekeke kwizinto ezininzi, kuquka KV, ifomu wave ombane, izinto anode kunye neqondo umonakalo wobuso kwisixhobo lokucoca kunye nexesha ukusetyenziswa.

KV kulawulo

Ombane KV X-ray ityhubhu ngempumelelo olawula radiation kwimveliso. Njengomgaqo, kulindeleke ukuba imveliso leyo ngokomlinganiselo isikweri KV. Ukuphinda exposure KV kwandisa ka-4.

amaza

Le amaza ichaza indlela apho KV yahluka kwexesha ngethuba isizukulwana radiation ngenxa yobume elibujikele bamandla. waveforms basebenzisa eziliqela. Umgaqo jikelele: i ezincinane utshintsho kwi KV imilo, yemisebe X-ray iyaveliswa ngokufanelekileyo. Isixhobo mihla kusetyenziswa umbane kunye KV rhoqo kakhulu.

ngemibhobho X-ray: Manufacturers

Oxford Instruments Inkampani silwenza izixhobo ezahlukeneyo, kubandakanywa iglasi, amandla 250 W, 4-80 kV isakhono, ebaluleke indawo 10 microns kwaye uluhlu olubanzi lwezixhobo anode, t. H. Ag, Au, Co, Cr, Cu, Fe, Mo, pd, RH, Chai, W.

Varian inikeza phezu 400 iintlobo ezahlukeneyo ze X-ray unyango kunye mveliso neetyhubhu. Nabanye abavelisi ezaziwayo Dunlee, uMbane kaWonke-wonke, Philips, Shimadzu, Siemens, Toshiba, IAE, Hangzhou Wandong, Kailong et al.

In Russia yavelisa neetyhubhu ze X-ray "USvetlana-Roentgen". Ukongeza kwizixhobo zemveli kunye ujikeleza kunye nenkampani anode emileyo silwenza iingcinga zabo cathode abandayo obhobhozayo ezikhanyayo elawulwayo. Inzuzo yamacebo zilandelayo:

• ukusebenza iindlela kuyaqhubeka kwaye ukubetha;
• ukungabikho inertia;
• olawula izinga kweyangoku i LED;
• spectrum ntumbuluko;
• amathuba X-ray radiation ngegalelo lazo.