Kev siv Electron Microscopes
Electron microscopes tuaj yeem muab faib ua kis tau tus mob electron microscopes, scanning electron microscopes, reflection electron microscopes, thiab emission electron microscopes raws li lawv cov qauv thiab kev siv. Kev xa hluav taws xob tshuab hluav taws xob feem ntau siv los saib xyuas cov khoom siv zoo uas tsis tuaj yeem daws tau los ntawm cov tshuab microscopes; scanning electron microscopes feem ntau yog siv los soj ntsuam cov morphology ntawm cov khoom siv, thiab tseem tuaj yeem ua ke nrog X-ray diffractometers lossis electron zog spectrometers los tsim hluav taws xob Cov microspheres yog tsim los ntawm kev tawg ntawm cov kab hluav taws xob los ntawm cov atoms ntawm cov qauv. Lub thinner los yog qis-density ib feem ntawm cov qauv muaj tsawg dua electron beam tawg, yog li ntawd cov electrons ntau dhau los ntawm lub hom phiaj diaphragm thiab koom rau hauv cov duab, thiab zoo li brighter hauv daim duab. Conversely, thicker los yog denser qhov chaw ntawm cov qauv tshwm darker nyob rau hauv daim duab. Yog hais tias tus qauv yog tuab heev los yog tuab heev, qhov sib piv ntawm cov duab yuav deteriorate, los yog txawm yuav puas los yog puas los ntawm absorbing lub zog ntawm lub electron beam.
Sab saum toj ntawm kis tau tus mob electron microscope lens chim yog ib rab phom electron. Cov electrons raug tso tawm los ntawm tungsten kub cathode, thiab cov kab hluav taws xob yog tsom los ntawm thawj thiab thib ob condensers. Tom qab dhau los ntawm cov qauv, cov kab hluav taws xob tau teeb tsa rau ntawm daim iav nruab nrab los ntawm lub hom phiaj lens, thiab tom qab ntawd nthuav tawm cov kauj ruam dhau los ntawm daim iav nruab nrab thiab daim iav tsom iav, thiab tom qab ntawd muab duab rau ntawm lub vijtsam fluorescent lossis cov phaj photocoherent.
Qhov kev nthuav dav ntawm daim iav nruab nrab tuaj yeem hloov pauv tsis tu ncua los ntawm kaum tawm lub sijhawm mus rau ntau pua txhiab lub sijhawm feem ntau los ntawm kev hloov pauv ntawm qhov excitation tam sim no; los ntawm kev hloov lub focal ntev ntawm daim iav nruab nrab, cov duab electron microscopic thiab electron diffraction dluab tuaj yeem tau txais ntawm qhov me me ntawm tib cov qauv. Txhawm rau kawm cov qauv hlau tuab dua, Fab Kis Dulos Electron Optics Laboratory tau tsim lub tshuab hluav taws xob ultra-high voltage electron microscope nrog rau qhov nrawm ntawm 3500 kV.
Lub teeb hluav taws xob ntawm lub tshuab hluav taws xob scanning tsis dhau los ntawm cov qauv, tab sis tsuas yog scans thiab ua rau cov khoom siv hluav taws xob thib ob nyob rau saum npoo ntawm cov qauv. Cov siv lead ua ci ntsa iab tso rau ib sab ntawm cov qauv tau txais cov khoom siv hluav taws xob thib ob, ua kom nrov nrov thiab hloov kho cov kab hluav taws xob siv hluav taws xob ntawm cov duab raj, yog li hloov qhov ci ntawm qhov screen ntawm lub raj duab. Lub deflection coil ntawm daim duab tube khaws synchronous scanning nrog lub electron beam nyob rau saum npoo ntawm cov qauv, yog li ntawd lub fluorescent screen ntawm daim duab raj tso saib cov duab topographic ntawm tus qauv nto, uas yog zoo ib yam li lub hauv paus ntsiab lus ua hauj lwm ntawm ib tug industrial TV. .
Qhov kev daws teeb meem ntawm lub tshuab ntsuas hluav taws xob ntsuas hluav taws xob feem ntau yog txiav txim siab los ntawm txoj kab uas hla ntawm lub teeb hluav taws xob ntawm cov qauv saum npoo. Qhov kev nthuav dav yog qhov piv ntawm qhov ntsuas amplitude ntawm daim duab raj mus rau qhov ntsuas amplitude ntawm tus qauv, uas tuaj yeem hloov pauv tsis tu ncua los ntawm kaum tawm mus rau ntau pua txhiab zaus. Scanning electron microscopy tsis xav tau cov qauv nyias nyias; daim duab muaj zog peb-dimensional nyhuv; nws tuaj yeem siv cov ntaub ntawv xws li cov khoom siv hluav taws xob thib ob, cov khoom siv hluav taws xob nqus, thiab X-rays tsim los ntawm kev sib cuam tshuam ntawm cov kab hluav taws xob thiab cov khoom siv los txheeb xyuas cov khoom muaj pes tsawg leeg.
Cov phom electron thiab condenser lens ntawm scanning electron microscope yog roughly tib yam li cov kis tau tus mob electron microscope, tab sis nyob rau hauv thiaj li yuav ua kom lub electron beam thinner, lub hom phiaj lens thiab ib tug astigmatizer yog ntxiv nyob rau hauv lub condenser lens, thiab ob pawg. Kev sib nrig sib txuas ntawm cov kab hluav taws xob tau teeb tsa hauv lub hom phiaj lens. coil. Cov qauv chamber hauv qab lub hom phiaj lens yog nruab nrog cov qauv theem uas tuaj yeem txav, tig thiab qaij.
