Kamar yadda X-ray shambura aiki?

X-haskoki ake generated da mayar da makamashi na electrons zuwa photons, wanda ya auku a X-ray tube. Quantity (fiddawa) da kuma ingancin (bakan) radiation za a iya gyara ta hanyar canza halin yanzu, irin ƙarfin lantarki da kuma lokacin da kayan aiki.

manufa na aiki

X-ray shambura (photo ba a cikin labarin) ne makamashi converters. Sun sami shi daga cibiyar sadarwa da kuma tuba a cikin sauran siffofin - iya shiga radiation da zafi, da karshen ne a ke so byproduct. X-ray tube na'urar irin wannan cewa maximizes samar da photons da ya lullube dukkanin zafi da sauri.

A tube ne mai gwada sauki na'urar, yawanci hada da biyu na asali abubuwa - a cathode da wani anode. Lokacin da na yanzu gudana daga cathode ga anode, electrons rasa ƙarfi, wadda take kaiwa zuwa ƙarni na X-haskoki.

anode

A anode ne a bangaren da, a cikinsu da watsi da high-makamashi photons samar. Wannan shi ne mai gwada da m karfe kashi wanda aka haɗa zuwa tabbatacce iyakacin duniya na lantarki kewaye. Yana yana da biyu main ayyuka:

• Yana sabobin tuba cikin electron makamashi cikin X-ray radiation,
• Yana lullube dukkanin zafi.

The abu ga anode aka zaba don bunkasa wadannan ayyuka.

Fi dacewa, mafi yawan electrons kamata samar da wata high-makamashi photons, maimakon zafi. Rabo na jimlar makamashi, wanda aka tuba zuwa X-radiation (Cop) ya dogara da dalilai biyu:

• atomic lamba (Z) na anode abu,
• electron makamashi.

A mafi x-ray shambura a matsayin abu na anode amfani da tungsten, wanda atomic lambar da yake daidai 74. Bugu da kari ga manyan Z, wannan ƙarfe yana da wasu sauran halaye, wanda yin shi dace da wannan manufa. Tungsten ne musamman a cikin ikon kula da ƙarfi a lõkacin mai tsanani, yana da babban narkewa batu da kuma a low danshin kudi.

Domin shekaru masu yawa, da anode aka sanya tsantsa tungsten. A cikin 'yan shekaru, za mu fara amfani da wannan karfe gami da rhenium, amma kawai a kan surface. Kai anode karkashin tungsten-rhenium shafi sanya haske abu, mai kyau zafi-ajiya. Biyu irin wannan abubuwa ne molybdenum da graphite.

A X-ray tube amfani ga mammography, an yi tare da anode, rufi da molybdenum. Wannan abu yana da wani tsaka-tsaki atomic lamba (Z = 42), wanda ya haifar da photons da halayyar makamashi, dace da rikodi kirji. Wasu mammography na'urorin ma da na biyu anode, kafa daga Rhodium (Z = 45). Wannan ya sa ya yiwu don kara samar da makamashi da kuma cimma mafi girma shigar azzakari cikin farji ga m ƙirãza.

A amfani da tungsten-rhenium gami inganta dogon lokacin da radiation fitarwa - tare da lokaci yadda ya dace da na'urorin da anode sanya tsantsa tungsten an rage saboda thermal lalacewar da surface.

Mafi yawa daga cikin anode yana da siffar da Tapered fayafai kuma gyarawa zuwa motor shaft, wanda rotates su a gwada high gudu a lokacin da watsi da X-haskoki. Dalilin da juyawa - kau da zafi.

mai da hankali tabo

A X-ray tsara rarraba ba dukan anode. Yana auku a wani karamin yanki na bãyan tẽkun - da mai da hankali tabo. Girma na karshe m size na electron katako zuwa daga cathode. A mafi yawan shi yana da rectangular siffar dabam a cikin 0.1-2 mm na'urorin.

A x-ray tube zane da wasu size na mai da hankali tabo. The karami shi ne, na ƙasa da motsi blur kuma mafi girma sharpness, da kuma abin da ya fi, da mafi alheri zafi masha'a.

Mai da hankali tabo size ne mai factor cewa dole ne a yi la'akari lokacin da zabar da X-ray tube. Masana'antun sarrafa na'urori tare da kananan mai da hankali tabo, inda shi wajibi ne don cimma high ƙuduri da kananan isa radiation. Alal misali, an da ake bukata a cikin binciken na kananan da kuma m sassa na jiki kamar yadda a mammography.

A X-ray tube yafi nuna mai da hankali spots tare da biyu masu girma dabam - manya da kananan, wanda za a iya zaba ta hanyar sadarwarka daidai da image kafa hanya.

cathode

Babban aiki na cathode - don samar da electrons da kuma tattara su a cikin wani gungume directed zuwa anode. Yana kullum kunshi wani kananan karkace waya (filament) saka a cikin wani kofin-dimbin yawa sako.

Electrons wucewa ta hanyar da kewaye ba zai iya kullum bar shugaba da kuma barin wani free sarari. Duk da haka, za su iya yi da shi, idan sun samu isasshen makamashi. A wani tsari da aka sani a matsayin thermal watsi, da zafi amfani ga fitar da electrons daga cathode. Wannan ya zama mai yiwuwa a lokacin da matsa lamba a wani kwashe x-ray tube kai 10 ^-6 -10 ^-7 Ki. Art. A yarn ne mai tsanani a cikin wannan hanya a matsayin karkace filament fitilar ta wucewa a halin yanzu therethrough. Aiki cathode ray tube yana tare da dumama zuwa da zazzabi luminescence kawar da thermal makamashi daga gare ta da electrons.

balan-balan

A anode da cathode suna kunshe ne a wani shãfe haske gidaje - Silinda. A balan-balan da kuma abinda ke ciki sukan kira a matsayin wani Saka, wanda yana da wata iyaka rayuwa da za a iya maye gurbinsu. A x-ray tube kullum da gilashin kwan fitila, ko da yake karfe da yumbu cylinders amfani ga wasu aikace-aikace.

Babban aiki shi ne don tallafa wa akwati da kadaici na anode da cathode, da kuma rike injin. A matsa lamba a kwashe x-ray tube a 15 ° C ne 1.2 × 10 ^-3 Pa. A gaban gas a cikin tanki zai ba da damar da wutar lantarki ga gudãna daga ƙarƙashinsu, a cikin na'urar kyauta, ba kawai a cikin nau'i na wani electron masaƙa.

gidaje

X-ray tube na'ura irin wannan cewa, ban da yadi da kuma goyon bayan sauran gyara, shi hidima a matsayin garkuwa jiki da kuma garwaya da radiation, fãce ga amfani katako wucewa ta cikin taga. Its gwada manyan waje surface lullube dukkanin mafi zafi generated a cikin na'urar. A sarari tsakanin harsashi da Saka da aka cika da mai da bayar da rufi da kuma sanyaya shi.

sarkar

A lantarki kewaye ta haɗu da wayar da wurin wuta source, wanda ake kira a janareta. Source powered daga cibiyar sadarwa da kuma sabobin tuba da alternating halin yanzu don kaitsaye halin yanzu. A janareta kuma ba ka damar daidaita wasu sigogi na sarkar:

• KV - ƙarfin lantarki ko lantarki m.
• MA - yanzu wanda gudana ta hanyar da tube.
• S - duration ko daukan hotuna lokaci, a kasarun adadi na biyu ne.

A kewaye samar da motsi na electrons. An tuhumi da makamashi, ta hanyar wucewa da janareta, kuma ba shi da anode. Kamar yadda su motsi faruwa biyu rikirkida:

• lantarki m makamashi ne tuba a cikin sanadin motsi makamashi.
• sanadin motsi, bi da bi, yana tuba zuwa X-ray radiation da kuma zafi.

m

Lokacin da electrons zo a cikin flask, da suka mallaka m na'urar samar da makamashi, wanda aka ƙaddara da adadin KV ƙarfin lantarki tsakanin anode da cathode. A X-ray tube aka sarrafa a wani irin ƙarfin lantarki don samar 1 KV wanda kowane barbashi dole 1 keV. By daidaitawa da KV, da sadarwarka yana kowane electron ne wani adadin na makamashi.

motsi

Low matsa lamba a wani kwashe x-ray tube (a 15 ° C da shi ne 10 ^-6 -10 ^-7 Ki. V.) Bayar da barbashi karkashin mataki na watsi da thermionic lantarki karfi jefarwa daga cathode ga anode. Wannan karfi accelerates su, sakamakon kara gudu da kuma sanadin motsi makamashi da kuma m, saukarwa. Lokacin da wani barbashi asashe kan anode, ta yuwuwar aka rasa, da kuma duk na samar da makamashi ne tuba zuwa cikin sanadin motsi makamashi. 100-keV electron kai gudun ta fi rabin haske gudun. Jifar surface na barbashi aka slowing sauka sosai da sauri da kuma rasa su sanadin motsi makamashi. Ta jũya zuwa X-haskoki ko kadan.

Electrons zo a cikin lamba tare da mutum sunadaran anode abu. Radiation generated da su hulda da orbitals (X-ray photons), kuma tare da wani core (bremsstrahlung).

dauri makamashi

Kowane electron a zarra yana da wani nauyin da makamashi, wanda ya dogara a kan girman da karshen da matakin a wadda barbashi aka located. Daure makamashi taka muhimmiyar rawa a cikin ƙarni na halayyar X-haskoki da ake bukata don cire wani electron daga zarra.

bremsstrahlung

Bremsstrahlung samar da mafi girma da yawan photons. A electrons shiga cikin anode abu da kuma mikawa kusa da tsakiya, deflected da decelerated gravitational karfi zarra. Su samar da makamashi rasa a lokacin wannan ganawar bayyana a cikin nau'i na X-ray photon.

da kewayon

Kawai 'yan photons da wani makamashi kusa da electron makamashi. Mafi yawan su shi ne m. Ɗauka cewa akwai wani sarari ko filin kewaye da zuciyar, cikinsa da electrons da kwarewa da karfi "hanawa." Wannan filin za a iya raba zones. Wannan ba wani ra'ayi na filin core da manufa zarra a cikin cibiyar. Lantarki fadowa ko ina a cikin manufa ne decelerated da ya haifar da wani X-ray photon. Barbashi cewa fada ya fi kusa da cibiyar, ne mafi fallasa da haka rasa mafi makamashi, samar da sosai high-makamashi photons. Electrons shiga cikin matsanancin zone fuskantar mai rauni hulda da kuma samar da photons na ƙananan makamashi. Ko da yake yankin da wannan nisa, cewa suna da wani daban-daban yankin dangane da nisa daga tsakiya. Tun da yawan barbashi faru a kan sashi, ya dogara a kan ta total yankin, shi ne bayyananne cewa external yanki kama mafi electrons da kuma haifar da mafi photons. makamashi X-ray bakan za a iya annabta da wannan model.

E _max photons babban bremsstrahlung bakan m to E _max electrons. Kasa wannan batu, tare da ragewa photon makamashi ƙara musu lamba.

A gagarumin yawan photons na low makamashi tunawa ko tace, kamar yadda suka yi yunkurin ratsa surface na anode tube ko akwatin tace. Tace ne kullum dogara a kan abun da ke ciki da kuma kauri daga cikin abu ta hanyar da katako wuce, kuma wannan kayyade karshe nau'i na low-makamashi bakan kwana.

tasiri KV

A high-makamashi ɓangare na bakan kayyade ƙarfin lantarki x-ray shambura a KV (kilovolt). Wannan shi ne saboda shi kayyade makamashi na electrons kai anode, kuma photons ba zai iya yi da m mafi girma daga wannan. A karkashin wani irin ƙarfin lantarki Gudun X-ray tube? Matsakaicin photon makamashi yayi dace da matsakaicin amfani m. Wannan irin ƙarfin lantarki za su iya bambanta a lokacin daukan hotuna saboda da alternating halin yanzu cibiyar sadarwa. A wannan yanayin, E _max ganiya ƙarfin lantarki ƙaddara da photon oscillation lokaci KV _p.

Bugu da ari m kamfani mai suna Quanta, KV _p kayyade adadin radiation generated da wani ba yawan electrons kai anode. Tun da total yadda ya dace da bremsstrahlung radiation an karu da lamarin electron makamashi ƙaruwa, wanda aka ƙaddara KV _p, wannan ya nuna cewa da KV _p rinjayar da yadda ya dace da na'urar.

Canza KV _p, yawanci musanyãwa ga bakan. A duka yankin a karkashin makamashi kwana wakiltar yawan photons. Unfiltered bakan ne alwatika, da kuma adadin radiation a gwargwado ga square KV. A gaban da tace kuma qara KV karuwa shigar azzakari cikin farji na photons, wanda rage kashi na tace radiation. Wannan take kaiwa zuwa ƙãra radiation amfanin ƙasa.

halayyar radiation

A irin hulda cewa ya haifar da halayyar radiation qunshi high-gudun karo da orbital electrons. Hulda iya kawai faru a lokacin da wani ɓangare E _na barbashi yana da mafi girma daga dauri makamashi zarra. Lokacin da wannan yanayin da aka hadu, kuma akwai a karo, da electron aka buga fita. Wannan ya bar bude matsayi, cike da barbashi a mafi girma makamashi matakin. Kamar yadda muka matsa da electron ba makamashi jefarwa a cikin nau'i na X-ray photon. Shi ne ake kira da halayyar radiation, tun E ne photon halayyar sinadari daga wanda anode aka yi. Alal misali, sa'ad da wani electron aka buga K tungsten Layer _dangane da E = 69.5 keV, da gurbi mai cike da wani electron daga L-matakin _sadarwar da E = 10.2 keV. Halayyar X-ray photon yana da makamashi daidaita da bambanci tsakanin biyu matakan, ko 59,3 keV.

A gaskiya ma, cikin anode abu take kaiwa zuwa wani yawan halayyar X-ray kuzari. Wannan na faruwa saboda electrons a daban-daban makamashi matakan (K, L, da dai sauransu) za a iya buga bombarding barbashi da ayyuka iya cike da wani iri-iri na makamashi matakan. Duk da yake cikin ayyuka L-matakin haifar photons da su kuzari ne ma kananan don amfani a bincike Dabarar. Kowane halayyar makamashi ne ba a nadi wanda yake nuna orbital, a cikinsa wani gurbi, tare da wani index wanda ya nuna wani electron tushen bukata. alpha (α) suturta da index of ciko electron daga L-matakin, da kuma beta (β) ya nuna cika matakin na M ko N.

• Bakan tungsten. A halayyar radiation na karfe samar da wani mikakke bakan kunsha da dama mai hankali kuzari da kuma braking haifar da ci gaba da rarraba. Yawan photons halitta ta kowane hali makamashi, halin a cewa yiwuwar samun cika gurbin K-matakin ya dogara da orbital.
• Bakan molybdenum. Anodes wannan karfe amfani ga mammography, samar da biyu isasshe m halayyar x-ray makamashi: K-alpha a 17,9 keV da K-beta a 19,5 keV. A ganiya kewayon X-ray shambura, wanda damar cimma mafi kyau daidaituwa tsakanin bambanci da kuma sakawa a iska mai guba kashi ga talakawan nono size cimma a E _p = 20 keV. Duk da haka Bremsstrahlung samar da karin makamashi. A mammography kayan aiki domin cire maras so sassa na bakan amfani molybdenum tace. Da tace aiki a kan manufa da «K-baki." Yana garwaya da radiation a wuce haddi electron dauri makamashi a K-matakin molybdenum zarra.
• Da bakan Rhodium. Rhodium yana atomic lambar 45, da kuma molybdenum - 42. Saboda haka, halayyar X-haskoki a Rhodium anode zai da dan kadan mafi girma makamashi fiye da na molybdenum kuma mafi iya shiga. Ana amfani da Dabarar m ƙirãza.

Anodes da biyu surface yankunan, molybdenum, Rhodium, ba dama da sadarwarka don zaɓi wani rarraba gyara domin ƙirãzansu, daga daban-daban size da yawa.

A sakamako a kan bakan KV

KV darajar ƙwarai rinjayar da halayyar radiation, watau. K. Yana ba za a iya samar idan kasa KV K-makamashi matakin electrons. Lokacin da KV ya wuce wannan bakin kofa darajar, da adadin radiation ne kullum gwargwado ga bambancin da dokin KV tube KV.

A samar da makamashi bakan photons na X-ray katako jefarwa daga na'urar da aka ƙaddara da dalilai da dama. Kamar yadda mai mulkin, shi kunshi bremsstrahlung da halayyar hulda.

A zumunta abun da ke ciki na bakan dogara a kan anode abu, KV da tace. A wani bututu da wani tungsten anode watsi da halayyar ba kafa a KV <69,5 keV. A mafi girma dabi'u na HF amfani da bincike da karatu, halayyar radiation qara total radiation zuwa 25%. A molybdenum na'urorin ya kai gare shi da babban rabo daga cikin jimlar sa iya aiki.

dace

Kawai karamin sashi na makamashi tsĩrar da electrons ne tuba zuwa cikin radiation. Babban sulusi da murabba'i ne tunawa da tuba a cikin zãfi. radiation yadda ya dace ne a tsare a matsayin sulusi da murabba'i na jimlar radiated ikon daga General Electric sanar anode. A dalilai da sanin da ya dace na X-ray tube ana amfani da ƙarfin lantarki KV da atomic yawan Z. A m rabo daga cikin wadannan:

• Yadda ya dace = KV x Z x 10 ^-6.

Dangantaka tsakanin dace da kuma KV yana da wani takamaiman sakamako a kan m amfani da X-ray kayan aiki. Saboda zafin rana tsara na tube da iyaka a kan yawan wutar lantarki da za su iya dissipate. Yana dora a kan damar da na'urar da iyaka. Tare da kara KV, duk da haka, adadin radiation samar da daya daga zafin rana muhimmanci ƙara.

A dogara da yadda ya dace da X-ray tsara a kan abun da ke ciki na anode ne kawai na ilimi amfani saboda mafi na'urorin amfani da tungsten. An togiya ne molybdenum da kuma azurfa, yi amfani da mammogram. Yadda ya dace da wadannan na'urori ne muhimmanci ƙananan for tungsten saboda su ƙananan atomic lambar.

tasiri

Yadda ya dace X-ray tube aka bayyana a matsayin adadin sakawa a iska mai guba millirentgenah tsĩrar da wani matsayi a cikin tsakiyar amfani katako a nesa na 1 m daga mai da hankali tabo ga kowane 1 Mas electrons wucewa ta cikin na'urar. Its darajar wakiltar da ikon da na'urar maida da makamashi na cajin barbashi a cikin X-ray radiation. Yana ba ka damar sanin da daukan hotuna na haƙuri, kuma hoto. Kamar yadda ya dace, yadda ya dace da na'urar dogara da dalilai da dama, ciki har da KV, da irin ƙarfin lantarki kalaman form, da anode abu da kuma digiri na surface lalacewar da tace na'urar da lokacin yin amfani.

KV-management

Awon karfin wuta KV X-ray tube yadda ya kamata iko da fitarwa radiation. Kamar yadda mai mulkin, shi ne a zaci cewa fitarwa ne na gwargwado ga square na KV. Anya KV daukan hotuna qara 4 sau.

waveform

A waveform bayyana Hanyar da wanda KV dabam tare da lokaci a lokacin ƙarni na radiation saboda da cyclic yanayi na iko. Used da dama daban-daban waveforms. A babban manufa ne: karami da canji a cikin siffar KV, da X-ray radiation aka samar da nagarta sosai. A zamani kayan aiki amfani da janareto da mun gwada m KV.

X-ray shambura: ƙera

Oxford Instruments Company ƙera daban-daban na'urorin, ciki har da gilashin, ikon zuwa 250 W, 4-80 KV m, da mai da hankali tabo 10 microns da mai fadi da kewayon anode kayan, t. H. Ag, Au, Co, Cr, Cu, Fe, Mo, PD, RH, Ti, W.

Nu yayi fiye da 400 daban-daban na likitanci da masana'antu X-ray shambura. Sauran sani kera ne Dunlee, GE, Philips, Shimadzu, Siemens, Toshiba, IAE, Hangzhou Wandong, Kailong et al.

A Rasha samar X-ray shambura "Svetlana-Roentgen". Bugu da kari gargajiya na'urorin tare da juyawa da tukwãne anode kamfanin ƙera na'urorin na sanyi cathode luminous juyi sarrafawa. Amfanin da wadannan na'urorin:

• aiki a ci gaba da kuma bugun jini halaye.
• babu inertia.
• gudãnar da tsanani na LED halin yanzu.
• bakan tsarki.
• da yiwuwar X-ray radiation mai sãɓãwar launukansa a tsanani.