Electron microscope qauv thiab imaging txoj cai
Lub tshuab ntsuas hluav taws xob muaj peb ntu: daim iav thoob, lub tshuab nqus tsev thiab lub txee fais fab. Lub thoob yog tsim los ntawm cov phom electron, electron lens, coj mus kuaj, fluorescent screen thiab yees duab mechanism, uas feem ntau yog sib sau ua ke rau hauv ib kem los ntawm sab saum toj mus rau hauv qab; lub tshuab nqus tsev yog tsim los ntawm cov tshuab nqus tsev twj tso kua mis, diffusion twj tso kua mis thiab lub tshuab nqus tsev vacuum, thiab lwm yam, thiab txuas nrog lub thoob los ntawm cov kav dej; lub hwj chim mov txee yog tsim los ntawm high-voltage generator, excitation tam sim no stabilizer thiab ntau yam kev cai tswj units.
◆ Electron Lens
Electron lens yog qhov tseem ceeb tshaj plaws ntawm electron microscope tube, uas siv qhov chaw hluav taws xob hauv hluav taws xob lossis cov hlau nplaum sib nqus sib luag rau cov axis ntawm lub raj kom cov electron khiav mus rau axis ntawm kev tsim ntawm lub ntsej muag ntawm lub iav convex. lens ua kom lub teeb ntawm lub teeb tsom lub luag hauj lwm zoo sib xws, yog li nws yog hu ua electron lens. Feem ntau ntawm cov niaj hnub electron microscopes siv electromagnetic lo ntsiab muag, nyob rau hauv uas cov electrons yog tsom los ntawm ib tug muaj zog magnetic teb generated los ntawm ib tug ruaj khov DC excitation tam sim no los ntawm ib tug coil nrog ib tug ncej khau.
◆ Phom hluav taws xob
Ib rab phom electron yog ib qho khoom siv uas muaj tungsten kub cathode, lub rooj vag thiab cathode. Nws emits thiab tsim ib lub teeb hluav taws xob nrog lub teeb nrawm, yog li kev ruaj ntseg ntawm qhov nrawm nrawm yuav tsum tsis pub tsawg dua ib feem ntawm kaum txhiab.
[Imaging Principple
■ Optical microscope imaging txoj cai
Thaum cov khoom yuav tsum tau pom nyob rau sab nraud ntawm lub hom phiaj ntawm lub hom phiaj lens ze ntawm lub focal point, tom qab lub hom phiaj lens ntawm cov duab tiag tiag tsim nyob rau hauv lub eyepiece tsom ze rau lub focal point ntawm lub eyepiece, lub eyepiece yog dua magnified mus rau hauv ib tug. duab virtual. Dab tsi yog pom yog ib daim duab inverted virtual tom qab ob magnifications.
■ electron microscope imaging txoj cai
Electron microscope yog raws li lub hauv paus ntsiab lus ntawm electron optics, electron beam thiab electron lo ntsiab muag es tsis txhob ntawm lub teeb beams thiab optical lo ntsiab muag, thiaj li hais tias cov qauv zoo ntawm cov khoom nyob rau hauv ib tug heev magnification ntawm lub imaging ntsuas.
Kev daws lub zog ntawm lub tshuab ntsuas hluav taws xob yog qhia los ntawm qhov tsawg kawg nkaus ntawm ob lub ntsiab lus nyob sib ze uas nws tuaj yeem daws tau.Hauv xyoo 1970s, qhov kev daws teeb meem ntawm lub tshuab hluav taws xob xa hluav taws xob yog li ntawm 0.3 nanometers ( qhov kev daws teeb meem ntawm tib neeg lub qhov muag yog li 0.1 millimeters). Niaj hnub no, qhov siab tshaj plaws ntawm lub tshuab ntsuas hluav taws xob yog ntau dua 3 lab lub sijhawm, thaum qhov siab tshaj plaws ntawm lub tshuab ntsuas qhov muag yog li 2, 000 zaug, kom cov atoms thiab crystals ntawm qee cov hlau hnyav tuaj yeem pom ncaj qha los ntawm electron microscope nrog cov txheej txheem zoo nkauj ntawm atomic dots.
