Working of SEM Microscopy

EXPERIMENT NO: 7 13 DATE / 12 2022 SCANNING ELECTRON MICROSCOPE - DEMONSTRATION shope is a type microorgamism of that uses a SEM, popularly known election as scanning microscope claison that min and scan specimens applying K.E to produce signals emite d beam of electrons The SEM on scans surfaces of moving at low works energy on the to focus the interaction These of elections are back seattere 2° electrons, d elections catter principle of the electrons (SEM uses banks which are used produce the spelimen image electro elections ns are and used diffranted to view onyst to allized an elements and photons They are emitted from role detect The 2° elutions an important primary the specime of ng while and the they the morphology an play backsattered and topography electrons show of contrast INSTRUMENTATION & WORKING source - Electrons are produced under There are thermal Electron heat of a voltage of 1-40 KV. Lantha num hexaboride and field emission gun. types of e- source ie, tungsten filament, henses - It has several condonser lenses It focus the beam of es from the beam source through the column forming a narrow of e-s (It forms a spot called 'spot size') scanning coil - It deflect the beam over the surface of the spelimen vauum system. Detector, display device, power supply and

14 Electrons are chased and fixed using an electron gun when auderales down the microscope passing through a beam, series these of lenses and apertures creating a focused the sample. the then sample interails is with the surface in of the chamber the mironcrope positioned on is created by of Dumps The a stage a of series before a valum coils control the position across of the e- beam, above the rean objective and lens, provides It scans information interaction the about surface between a of the sample area under study. The number the sample in the form of 2° these or produce defined and the electrons will back produce seattered a clunor of signals detectors will detect on signals a computer us screen. The images when are thus displayed produces images by scanning SEM the when is yidely used in medical etc. sample with The a high energy beam science, of electrons biologi forensic investigations of Higs