Peb paub dab tsi txog X-rays?

2024 Tus sau: Seth Attwood | [email protected]. Kawg hloov kho: 2023-12-16 16:06

Nyob rau hauv lub xyoo pua puv 19, hluav taws xob pom tsis tau rau tib neeg lub qhov muag, muaj peev xwm hla ntawm cev nqaij daim tawv thiab lwm yam ntaub ntawv, zoo li ib yam dab tsi zoo heev. Tam sim no, X-rays tau siv dav los tsim cov duab kho mob, ua hluav taws xob kho mob, txheeb xyuas cov duab kos duab thiab daws teeb meem nuclear zog.

X-ray hluav taws xob tau tshawb pom li cas thiab nws pab tib neeg li cas - peb paub nrog tus kws kho mob Alexander Nikolaevich Dolgov.

Kev tshawb pom ntawm X-rays

Los ntawm qhov kawg ntawm lub xyoo pua puv 19, kev tshawb fawb tau pib ua lub luag haujlwm tshiab hauv kev tsim cov duab ntawm lub ntiaj teb. Ib puas xyoo dhau los, kev ua ub no ntawm cov kws tshawb fawb yog ib qho kev nyiam ua haujlwm thiab tus kheej. Txawm li cas los xij, los ntawm qhov kawg ntawm lub xyoo pua 18th, raws li kev hloov pauv ntawm kev tshawb fawb thiab thev naus laus zis, kev tshawb fawb tau hloov mus rau hauv kev ua haujlwm uas txhua qhov kev tshawb pom tau ua tau ua tsaug rau kev koom tes ntawm ntau tus kws tshaj lij.

Cov koom haum tshawb fawb, cov ntawv xov xwm tshawb fawb raws sij hawm pib tshwm sim, kev sib tw thiab kev tawm tsam tshwm sim rau kev lees paub txog kev cai lij choj rau kev ua tiav kev tshawb fawb thiab kev tsim kho tshiab. Tag nrho cov txheej txheem no tau tshwm sim nyob rau hauv German Empire, qhov twg thaum kawg ntawm lub xyoo pua 19th, Kaiser txhawb kev tshawb fawb ua tiav uas ua rau lub teb chaws muaj koob meej nyob rau hauv lub ntiaj teb theem.

Ib tug ntawm cov kws tshawb fawb uas ua haujlwm nrog kev txaus siab rau lub sijhawm no yog tus xibfwb ntawm physics, rector ntawm University of Würzburg Wilhelm Konrad Roentgen. Thaum lub Kaum Ib Hlis 8, 1895, nws nyob lig hauv chav kuaj, raws li feem ntau tshwm sim, thiab txiav txim siab los ua ib qho kev sim kawm txog cov hluav taws xob tawm hauv iav lub tshuab nqus tsev raj. Nws ua kom tsaus hauv chav thiab qhwv ib lub raj rau hauv daim ntawv opaque dub kom yooj yim rau kev soj ntsuam cov xwm txheej kho qhov muag uas nrog cov paug tawm. Ua rau kuv xav tsis thoob

Roentgen pom cov fluorescence band ntawm ib qho screen nyob ze uas npog nrog barium cyanoplatinite crystals. Nws tsis zoo li tias tus kws tshawb fawb tuaj yeem xav txog tias nws nyob rau ntawm qhov chaw ntawm ib qho tseem ceeb tshaj plaws kev tshawb pom ntawm nws lub sijhawm. Xyoo tom ntej, ntau tshaj li ib txhiab kev tshaj tawm yuav raug sau txog X-rays, cov kws kho mob yuav tam sim ntawd muab qhov kev tsim kho rau hauv kev pabcuam, ua tsaug rau nws, xov tooj cua yuav raug tshawb pom yav tom ntej thiab cov lus qhia tshiab ntawm kev tshawb fawb yuav tshwm sim.

Roentgen tau mob siab rau ob peb lub lis piam tom ntej no los tshawb xyuas qhov xwm txheej ntawm lub ntsej muag tsis paub qab hau thiab pom tias fluorescence tshwm sim thaum twg nws siv tam sim no rau lub raj. Lub raj yog lub hauv paus ntawm cov hluav taws xob, tsis yog lwm qhov ntawm cov hluav taws xob hluav taws xob, tsis paub tias nws tab tom ntsib dab tsi, Roentgen txiav txim siab xaiv qhov tshwm sim no ua X-rays, lossis X-rays. Ntxiv mus Roentgen tau tshawb pom tias cov hluav taws xob no tuaj yeem nkag mus yuav luag txhua yam khoom mus rau qhov sib txawv, nyob ntawm qhov tuab ntawm cov khoom thiab qhov ntom ntawm cov khoom.

Yog li, ib qho me me ntawm cov hlau lead ntawm lub raj xa tawm thiab lub vijtsam tig tawm ua rau tsis zoo rau x-rays, thiab cov pob txha ntawm tes tau muab cov duab ntxoov ntxoo tsaus rau ntawm qhov screen, ncig los ntawm cov duab ntxoov ntxoo ntawm cov ntaub so ntswg. Tsis ntev, tus kws tshawb fawb pom tau tias X-rays ua rau tsis yog tsuas yog lub teeb ci ntawm lub vijtsam npog nrog barium cyanoplatinite, tab sis kuj ua rau qhov tsaus ntuj ntawm daim phiaj duab (tom qab kev loj hlob) hauv cov chaw uas X-rays poob ntawm cov duab emulsion.

Hauv chav kawm ntawm nws qhov kev sim, Roentgen tau ntseeg tias nws tau pom hluav taws xob tsis paub txog kev tshawb fawb. Thaum Lub Kaum Ob Hlis 28, 1895, nws tau tshaj tawm txog kev tshawb fawb hauv ib tsab xov xwm "Rau ib hom hluav taws xob tshiab" hauv phau ntawv Journal Annals of Physics thiab Chemistry. Nyob rau tib lub sijhawm, nws tau xa cov kws tshawb fawb txog cov duab ntawm tes ntawm nws tus poj niam, Anna Bertha Ludwig, uas tom qab ntawd tau nto moo.

Ua tsaug rau Roentgen tus phooj ywg qub, Austrian physicist Franz Exner, cov neeg nyob hauv Vienna yog thawj tus pom cov duab no thaum Lub Ib Hlis 5, 1896 ntawm nplooj ntawv xov xwm Die Presse. Hnub tom qab, cov ntaub ntawv hais txog qhov qhib tau xa mus rau London Chronicle ntawv xov xwm. Yog li qhov kev tshawb pom ntawm Roentgen maj mam pib nkag mus rau hauv lub neej niaj hnub ntawm tib neeg. Daim ntawv thov tswv yim tau pom yuav luag tam sim: Lub Ib Hlis 20, 1896, hauv New Hampshire, cov kws kho mob tau kho tus txiv neej nrog caj npab tawg siv txoj kev kuaj mob tshiab - X-ray.

Thaum ntxov siv X-rays

Tau ntau xyoo, cov duab X-ray tau pib siv los ua haujlwm kom raug. Twb tau 14 hnub tom qab lawv qhib, Friedrich Otto Valkhoff coj thawj qhov chaw kho hniav X-ray. Thiab tom qab ntawd, ua ke nrog Fritz Giesel, lawv tau tsim lub ntiaj teb thawj qhov chaw kuaj hniav X-ray.

Los ntawm 1900, 5 xyoos tom qab nws tshawb pom, kev siv X-rays hauv kev kuaj mob tau suav tias yog ib feem tseem ceeb ntawm kev kho mob.

Cov ntaub ntawv txheeb cais los ntawm lub tsev kho mob qub tshaj plaws hauv Pennsylvania tuaj yeem suav tias yog qhov qhia txog kev sib kis ntawm cov thev naus laus zis raws li X-ray hluav taws xob. Raws li nws, xyoo 1900, tsuas yog li 1-2% ntawm cov neeg mob tau txais kev pabcuam X-rays, thaum xyoo 1925 muaj 25%.

X-rays tau siv nyob rau hauv txoj kev txawv heev thaum lub sijhawm. Piv txwv li, lawv tau siv los muab cov kev pabcuam tshem tawm cov plaub hau. Rau lub sijhawm ntev, txoj kev no tau suav tias yog qhov zoo dua nyob rau hauv kev sib piv nrog cov mob ntau dua - forceps lossis siv quav ciab. Tsis tas li ntawd, X-rays tau siv rau hauv khau haum apparatuses - sim-on fluoroscopes (pedoscopes). Cov no yog cov tshuab xoo hluav taws xob uas muaj lub cim tshwj xeeb rau cov taw, nrog rau cov qhov rais uas cov neeg siv khoom thiab cov neeg muag khoom tuaj yeem ntsuas seb cov khau zaum li cas.

Kev siv thaum ntxov ntawm X-ray duab los ntawm kev pom kev nyab xeeb niaj hnub no ua rau ntau cov lus nug. Qhov teeb meem yog tias thaum lub sij hawm tshawb pom ntawm X-rays, xyaum tsis muaj dab tsi paub txog hluav taws xob thiab nws qhov tshwm sim, uas yog vim li cas cov pioneers uas siv cov khoom tsim tshiab tau ntsib nws cov teeb meem hauv lawv tus kheej kev paub. tau dhau los ua qhov tshwm sim loj ntawm qhov tig ntawm lub xyoo pua 19th. XX centuries, thiab tib neeg pib maj mam los txog qhov kev txaus ntshai ntawm kev siv lub hlwb tsis xav siv X-rays.

Qhov xwm ntawm x-rays

X-ray hluav taws xob yog hluav taws xob hluav taws xob hluav taws xob nrog photon energies los ntawm ~ 100 eV mus rau 250 keV, uas nyob ntawm qhov ntsuas ntawm electromagnetic nthwv dej ntawm ultraviolet hluav taws xob thiab gamma hluav taws xob. Nws yog ib feem ntawm lub ntuj hluav taws xob uas tshwm sim nyob rau hauv radioisotopes thaum lub atoms ntawm lub ntsiab yog zoo siab los ntawm ib tug kwj ntawm electrons, alpha hais los yog gamma quanta, nyob rau hauv uas electrons yog ejected los ntawm lub electron plhaub ntawm lub atom. X-ray hluav taws xob tshwm sim thaum them cov khoom txav nrog kev nrawm, tshwj xeeb, thaum cov hluav taws xob qis qis, hauv hluav taws xob ntawm atoms ntawm cov khoom.

Mos thiab tawv X-rays yog qhov txawv, qhov xwm txheej ntawm ciam teb ntawm qhov ntsuas ntawm lub wavelength yog li 0.2 nm, uas sib raug rau lub zog photon txog 6 keV. X-ray hluav taws xob yog ob qho tib si nkag mus, vim nws qhov luv wavelength, thiab ionizing, txij li thaum dhau los ntawm ib yam khoom, nws cuam tshuam nrog electrons, khob lawv tawm ntawm atoms, yog li rhuav tshem lawv mus rau hauv ions thiab electrons thiab hloov cov qauv ntawm cov khoom. uas nws ua.

X-rays ua rau muaj tshuaj lom neeg hu ua fluorescence kom ci. Irradiating cov atoms ntawm cov qauv nrog high-zog photons ua rau lub emission ntawm electrons - lawv tawm hauv lub atom. Nyob rau hauv ib los yog ntau dua electron orbitals, "qhov" yog tsim - vacancy, vim hais tias cov atoms mus rau hauv ib tug zoo siab lub xeev, uas yog, lawv ua tsis ruaj tsis khov. Ntau lab ntawm ib thib ob tom qab, cov atoms rov qab mus rau lub xeev ruaj khov, thaum cov chaw ua haujlwm nyob rau hauv lub puab orbitals tau ntim nrog electrons los ntawm sab nrauv orbitals.

Qhov kev hloov no yog nrog los ntawm emission ntawm lub zog nyob rau hauv daim ntawv ntawm ib tug thib ob photon, li no fluorescence tshwm sim.

X-ray astronomy

Hauv ntiaj teb, peb tsis tshua pom X-rays, tab sis feem ntau pom muaj nyob hauv qhov chaw. Nyob ntawd nws tshwm sim lawm vim yog kev ua ntawm ntau qhov chaw khoom. Qhov no ua rau X-ray astronomy ua tau. Lub zog ntawm X-ray photons yog siab dua li cov khoom siv kho qhov muag, yog li ntawd, nyob rau hauv X-ray ntau nws emits ib yam khoom rhuab mus rau qhov kub siab heev.

Cov chaw cosmic ntawm X-ray hluav taws xob tsis yog ib feem ntawm lub ntuj tsim hluav taws xob rau peb thiab yog li ntawd tsis hem tib neeg nyob rau hauv ib txoj kev. Qhov tsuas yog qhov tshwj xeeb tuaj yeem yog qhov nyuaj ntawm hluav taws xob hluav taws xob hluav taws xob ua hluav taws xob supernova tawg, uas tshwm sim ze txaus rau lub hnub ci.

Yuav ua li cas los tsim X-rays artificially?

X-ray cov cuab yeej tseem siv dav siv rau kev ua kom tsis muaj kev puas tsuaj (X-ray duab hauv tshuaj, kev kuaj pom qhov tsis zoo hauv tshuab). Lawv cov khoom tseem ceeb yog X-ray raj, uas muaj cov cathode thiab anode. Lub raj electrodes txuas nrog lub zog hluav taws xob siab, feem ntau kaum lossis ntau pua txhiab volts. Thaum rhuab, lub cathode emits electrons, uas yog ceev los ntawm lub generated hluav taws xob teb ntawm lub cathode thiab lub anode.

Sib tsoo nrog cov anode, cov electrons yog decelerated thiab poob feem ntau ntawm lawv lub zog. Nyob rau hauv rooj plaub no, bremsstrahlung hluav taws xob ntawm X-ray ntau yam tshwm sim, tab sis qhov tseem ceeb ntawm cov hluav taws xob hluav taws xob hloov mus rau hauv tshav kub, yog li lub anode txias.

X-ray raj ntawm qhov tsis tu ncua lossis kev ua haujlwm ntawm tes yog qhov tseem ceeb tshaj plaws ntawm X-ray hluav taws xob, tab sis nws nyob deb ntawm ib qho xwb. Txhawm rau kom tau txais cov hluav taws xob siv hluav taws xob siab, cov hluav taws xob tam sim no tau siv, uas cov plasma channel ntawm cov dej ntws tam sim no compressed los ntawm nws tus kheej magnetic teb ntawm tam sim no - lub thiaj li hu ua pinching.

Yog hais tias qhov paug tshwm sim nyob rau hauv nruab nrab ntawm lub teeb ntsiab, piv txwv li, nyob rau hauv ib tug hydrogen nruab nrab, ces nws plays lub luag hauj lwm ntawm ib tug zoo accelerator ntawm electrons los ntawm hluav taws xob teb tshwm sim nyob rau hauv lub paug nws tus kheej. Qhov kev tso tawm no tuaj yeem ua tau ntau tshaj qhov chaw tsim los ntawm qhov chaw sab nraud tam sim no. Nyob rau hauv txoj kev no, pulses ntawm nyuaj X-ray hluav taws xob nrog lub zog siab ntawm generated quanta (ntau pua ntawm kiloelectronvolts), uas muaj lub siab nkag mus rau lub zog, tau txais.

Yuav kom tau X-rays nyob rau hauv ib tug dav spectral ntau yam, electron accelerators - synchrotrons yog siv. Nyob rau hauv lawv, hluav taws xob yog tsim nyob rau hauv ib tug annular lub tshuab nqus tsev chamber, nyob rau hauv uas ib tug nqaim taw qhia beam ntawm high-zog electrons, accelerated yuav luag rau qhov ceev ntawm lub teeb, tsiv nyob rau hauv ib ncig orbit. Thaum lub sij hawm kev sib hloov, nyob rau hauv lub zog ntawm ib tug sib nqus teb, ya electrons emit beams ntawm photons tangentially rau lub orbit nyob rau hauv ib tug dav spectrum, qhov siab tshaj plaws ntawm uas ntog nyob rau hauv lub X-ray ntau yam.

Yuav kuaj X-ray li cas

Tau ntev, ib txheej nyias ntawm phosphor lossis duab emulsion tau siv rau saum npoo ntawm iav phaj lossis pob tshab polymer zaj duab xis tau siv los ntsuas thiab ntsuas X-ray hluav taws xob. Thawj qhov ci ntsa iab nyob rau hauv qhov muag ntau yam ntawm spectrum nyob rau hauv qhov kev txiav txim ntawm X-ray hluav taws xob, thaum lub optical transparency ntawm txheej hloov nyob rau hauv cov zaj duab xis nyob rau hauv qhov kev txiav txim ntawm ib tug tshuaj tiv thaiv.

Tam sim no, cov khoom siv hluav taws xob feem ntau yog siv los sau npe X-ray hluav taws xob - cov khoom siv uas tsim hluav taws xob mem tes thaum lub quantum ntawm hluav taws xob yog absorbed nyob rau hauv lub rhiab ntim ntawm lub ntes. Lawv txawv nyob rau hauv lub hauv paus ntsiab lus ntawm converting lub zog ntawm absorbed hluav taws xob mus rau hauv hluav taws xob signals.

X-ray detectors nrog cov ntawv sau npe hauv hluav taws xob tuaj yeem muab faib ua ionization, qhov kev txiav txim yog raws li ionization ntawm ib yam khoom, thiab radioluminescent, nrog rau scintillation, siv lub luminescence ntawm ib yam khoom nyob rau hauv qhov kev txiav txim ntawm ionizing hluav taws xob. Ionization detectors, nyob rau hauv lem, muab faib ua gas-filled thiab semiconductor, nyob ntawm seb qhov nruab nrab nrhiav tau.

Cov khoom tseem ceeb ntawm cov khoom siv roj puv yog ionization chambers, Geiger cov txee (Geiger-Muller cov txee) thiab cov txee faib cov pa tawm. Radiation quanta nkag mus rau qhov chaw ua haujlwm ntawm lub txee ua rau ionization ntawm cov pa roj thiab cov dej ntws ntawm tam sim no, uas tau sau tseg. Nyob rau hauv ib tug semiconductor detector, electron-qhov khub yog tsim nyob rau hauv qhov kev txiav txim ntawm hluav taws xob quanta, uas kuj ua rau nws muaj peev xwm rau ib tug hluav taws xob tam sim no ntws los ntawm lub cev ntawm lub detector.

Lub ntsiab tivthaiv ntawm scintillation txee nyob rau hauv lub tshuab nqus tsev twj yog ib tug photomultiplier raj (PMT), uas siv lub photoelectric nyhuv los hloov hluav taws xob mus rau hauv ib tug kwj ntawm nqi hais thiab qhov tshwm sim ntawm theem nrab electron emission los txhim kho cov tam sim no ntawm cov generated charged hais. Lub photomultiplier muaj ib tug photocathode thiab ib tug system ntawm sequential accelerating electrodes - dynodes, raws li qhov cuam tshuam rau qhov uas ceev electrons multiply.

Secondary electron multiplier yog lub tshuab nqus tsev qhib (ua haujlwm tsuas yog nyob rau hauv lub tshuab nqus tsev), nyob rau hauv uas X-ray hluav taws xob ntawm cov tswv yim hloov mus rau hauv cov kwj ntawm thawj electrons thiab ces amplified vim lub thib ob emission ntawm electrons raws li lawv propagate nyob rau hauv lub multiplier channel..

Microchannel daim hlau, uas yog ib tug loj tus naj npawb ntawm cais microscopic channel uas nkag mus rau lub phaj detector, ua hauj lwm raws li tib txoj cai. Lawv tuaj yeem muab cov kev daws teeb meem spatial thiab tsim cov duab kho qhov muag ntawm ntu ntu ntawm qhov xwm txheej flux ntawm tus ntes ntawm X-ray hluav taws xob los ntawm kev foob pob hluav taws xob tawm ntawm lub vijtsam semitransparent nrog phosphor tso rau ntawm nws.

X-rays hauv tshuaj

Lub peev xwm ntawm X-rays kom ci los ntawm cov khoom siv tsis yog tsuas yog muab rau tib neeg lub peev xwm los tsim cov X-rays yooj yim, tab sis kuj qhib qhov muaj peev xwm rau cov cuab yeej kuaj mob siab dua. Piv txwv li, nws yog nyob rau hauv lub plawv ntawm xam tomography (CT).

X-ray qhov chaw thiab receiver tig rau hauv lub nplhaib uas tus neeg mob dag. Cov ntaub ntawv tau txais yuav ua li cas cov ntaub so ntswg ntawm lub cev nqus X-rays yog reconstructed los ntawm lub computer mus rau hauv ib tug 3D duab. CT yog qhov tseem ceeb tshwj xeeb rau kev kuaj mob stroke, thiab txawm hais tias nws tsis tshua muaj tseeb dua li kev sib nqus resonance ntawm lub hlwb, nws yuav siv sij hawm tsawg dua.

Ib qho kev taw qhia tshiab, uas tam sim no tab tom txhim kho hauv microbiology thiab tshuaj, yog siv cov hluav taws xob xoo hluav taws xob. Thaum cov kab mob muaj sia nyob yog translucent, nws ua rau kom tau txais cov duab ntawm cov hlab ntsha, kawm paub meej cov qauv ntawm cov ntaub so ntswg, thiab txawm tias ua tiav cov kev tshawb fawb microbiological ntawm qib cellular.

X-ray microscope siv hluav taws xob los ntawm pinch-hom tso tawm hauv cov ntshav ntawm cov ntsiab lus hnyav ua rau nws pom tau cov ntsiab lus ntawm cov qauv ntawm cov cell nyob,uas tsis tuaj yeem pom los ntawm electron microscope txawm nyob rau hauv ib qho tshwj xeeb npaj cellular qauv.

Ib hom kev kho hluav taws xob siv los kho cov qog nqaij hlav qog nqaij hlav siv cov X-rays nyuaj, uas tuaj yeem ua tau vim nws cov nyhuv ionizing, uas rhuav tshem cov ntaub so ntswg ntawm cov khoom lom. Nyob rau hauv cov ntaub ntawv no, ib tug electron accelerator yog siv raws li ib tug hluav taws xob qhov chaw.

Radiography hauv technology

Mos X-rays yog siv rau hauv kev tshawb fawb los daws qhov teeb meem ntawm kev tswj hwm thermonuclear fusion. Txhawm rau pib cov txheej txheem, koj yuav tsum tsim kom muaj qhov rov qab poob siab nthwv dej los ntawm irradiating lub me me deuterium thiab tritium lub hom phiaj nrog cov X-rays los ntawm cov hluav taws xob tawm thiab tam sim cua sov lub plhaub ntawm lub hom phiaj no rau lub xeev ntshav.

Qhov no yoj compresses lub hom phiaj cov ntaub ntawv mus rau ib tug ceev phav phav lub sij hawm siab tshaj qhov ceev ntawm ib tug khoom, thiab heats nws mus rau ib tug thermonuclear kub. Kev tso tawm ntawm thermonuclear fusion zog tshwm sim nyob rau hauv ib lub sij hawm luv luv, thaum lub kub plasma tawg los ntawm inertia.

Lub peev xwm ntawm translucent ua rau muaj peev xwm radiography - cov txheej txheem kev yees duab uas tso cai rau koj los tso saib cov qauv sab hauv ntawm cov khoom opaque ua los ntawm hlau, piv txwv li. Nws tsis tuaj yeem txiav txim siab los ntawm qhov muag seb tus choj cov qauv puas tau ruaj khov, seb lub seam ntawm lub raj xa hluav taws xob puas yog airtight thiab seb cov ntsia hlau puas haum rau ib leeg.

Yog li ntawd, nyob rau hauv kev lag luam, X-ray yog siv rau qhov tsis pom kev - saib xyuas qhov kev ntseeg siab ntawm cov khoom tseem ceeb ntawm kev ua haujlwm thiab qhov tsis zoo ntawm cov khoom lossis nws tus kheej cov ntsiab lus, uas tsis tas yuav siv cov khoom tawm ntawm kev pabcuam lossis rhuav tshem nws.

X-ray fluorescence spectrometry yog raws li cov nyhuv ntawm fluorescence - ib txoj kev tsom xam siv los txiav txim siab cov ntsiab lus ntawm beryllium mus rau uranium nyob rau hauv thaj tsam ntawm 0,0001 mus rau 100% nyob rau hauv cov khoom ntawm ntau yam keeb kwm.

Thaum tus qauv yog irradiated nrog ib tug haib flux ntawm hluav taws xob los ntawm ib tug X-ray raj, cov yam ntxwv fluorescent tawg ntawm atoms tshwm, uas yog proportional rau lawv concentration nyob rau hauv cov qauv. Tam sim no, xyaum txhua lub tshuab ntsuas hluav taws xob ua rau nws tuaj yeem txiav txim siab, tsis muaj qhov nyuaj, cov ncauj lus kom ntxaws ntawm cov khoom siv micro-txoj kev tshawb fawb los ntawm txoj kev tsom xam X-ray fluorescence.

X-rays hauv keeb kwm kos duab

Lub peev xwm ntawm X-rays kom ci los ntawm thiab tsim cov nyhuv fluorescence kuj yog siv los kawm cov duab kos duab. Dab tsi yog muab zais rau hauv lub tsho tiv no saum toj kawg nkaus ntawm cov xim tuaj yeem qhia ntau yam txog keeb kwm ntawm kev tsim cov canvas. Piv txwv li, nws yog nyob rau hauv kev txawj ntse ua hauj lwm nrog ob peb txheej ntawm cov xim uas ib tug duab tuaj yeem pom muaj qhov tshwj xeeb hauv kev ua yeeb yam. Nws tseem yog ib qho tseem ceeb uas yuav tau coj mus rau hauv tus account tus qauv ntawm cov khaubncaws sab nraud povtseg ntawm cov painting thaum xaiv qhov zoo tshaj plaws cia tej yam kev mob rau lub canvas.

Rau tag nrho cov no, X-ray hluav taws xob yog qhov tsis tseem ceeb, tso cai rau koj saib hauv qab cov khaubncaws sab nraud povtseg ntawm daim duab yam tsis muaj teeb meem rau nws.

Cov kev txhim kho tseem ceeb hauv cov kev taw qhia no yog cov txheej txheem tshiab tshwj xeeb rau kev ua haujlwm nrog cov duab kos duab. Macroscopic fluorescence yog ib qho txawv ntawm X-ray fluorescence tsom xam uas zoo haum rau kev pom cov qauv kev faib tawm ntawm cov ntsiab lus tseem ceeb, feem ntau yog hlau, tam sim no nyob rau thaj tsam ntawm 0.5-1 square meter lossis ntau dua.

Ntawm qhov tod tes, X-ray laminography, qhov sib txawv ntawm kev suav X-ray tomography, uas yog qhov tsim nyog rau kev kawm cov chaw tiaj tus, zoo li cog lus kom tau txais cov duab ntawm ib tus neeg txheej ntawm daim duab. Cov txheej txheem no kuj tseem siv tau los kawm txog cov tshuaj muaj pes tsawg leeg ntawm cov xim txheej. Qhov no tso cai rau lub canvas hnub tim, suav nrog txhawm rau txheeb xyuas qhov cuav.

X-rays tso cai rau koj kom pom cov qauv ntawm cov khoom

X-ray crystallography yog ib qho kev qhia txuj ci cuam tshuam nrog kev txheeb xyuas cov qauv ntawm cov teeb meem ntawm qib atomic thiab molecular. Ib qho tshwj xeeb ntawm lub cev crystalline yog ntau qhov kev txiav txim rov ua dua nyob rau hauv cov qauv spatial ntawm tib lub ntsiab (hlwb), uas muaj qee yam ntawm atoms, molecules lossis ions.

Txoj kev tshawb fawb tseem ceeb muaj nyob rau hauv kev nthuav tawm cov qauv crystalline rau lub nqaj nqaim ntawm X-rays siv lub koob yees duab X-ray. Cov duab uas tshwm sim qhia tau hais tias ib daim duab ntawm cov duab X-rays dhau los ntawm cov siv lead ua, uas cov kws tshawb fawb tuaj yeem pom nws cov qauv spatial, hu ua crystal lattice. Ntau txoj hauv kev ntawm kev siv cov qauv no yog hu ua X-ray structural analysis.

X-ray structural tsom xam ntawm crystalline tshuaj muaj ob theem:

1. Kev txiav txim siab ntawm qhov loj ntawm chav tsev ntawm cov siv lead ua, tus naj npawb ntawm cov khoom (atoms, molecules) nyob rau hauv chav tsev cell thiab symmetry ntawm kev npaj ntawm cov khoom. Cov ntaub ntawv no tau txais los ntawm kev txheeb xyuas qhov geometry ntawm qhov chaw ntawm qhov diffraction maxima.
2. Kev suav ntawm electron ceev hauv chav tsev cell thiab kev txiav txim siab ntawm atomic coordinates, uas tau txheeb xyuas nrog txoj hauj lwm ntawm electron ceev maxima. Cov ntaub ntawv no tau txais los ntawm kev tshuaj xyuas qhov siv ntawm qhov diffraction maxima.

Qee cov kws tshawb fawb molecular tau kwv yees tias hauv kev ntsuas qhov loj tshaj plaws thiab qhov nyuaj tshaj plaws, X-ray crystallography yuav raug hloov los ntawm cov txheej txheem tshiab hu ua cryogenic electron microscopy.

Ib qho ntawm cov cuab yeej tshiab tshaj plaws hauv kev tshuaj xyuas tshuaj yog Henderson lub tshuab luam ntawv zaj duab xis, uas nws siv hauv nws txoj haujlwm pioneering hauv cryogenic electron microscopy. Txawm li cas los xij, txoj kev no tseem kim heev thiab yog li tsis zoo li yuav hloov X-ray crystallography nyob rau yav tom ntej.

Ib cheeb tsam tshiab ntawm kev tshawb fawb thiab kev siv txuj ci cuam tshuam nrog kev siv X-rays yog X-ray microscopy. Nws yog tsim los kom tau txais ib daim duab loj ntawm cov khoom nyob rau hauv kev kawm hauv qhov chaw tiag tiag hauv ob lossis peb qhov loj me uas siv tsom optics.

Lub diffraction txwv ntawm spatial daws teeb meem nyob rau hauv X-ray microscopy vim lub me me wavelength ntawm cov hluav taws xob siv yog hais txog 1000 lub sij hawm zoo dua tus nqi coj mus rau ib tug optical microscope. Tsis tas li ntawd, lub zog nkag mus ntawm X-ray hluav taws xob ua rau nws muaj peev xwm kawm txog cov qauv sab hauv ntawm cov qauv uas yog opaque kom pom lub teeb.

Thiab txawm hais tias electron microscopy muaj qhov zoo ntawm qhov kev daws teeb meem siab dua me ntsis, nws tsis yog txoj kev tshawb nrhiav tsis muaj kev puas tsuaj, vim nws xav tau lub tshuab nqus tsev thiab cov qauv nrog cov hlau los yog metallized nto, uas yog kev puas tsuaj tag nrho, piv txwv li, rau cov khoom siv roj ntsha.