A REVIEW ON ELECTRON PROBE MICRO ANALYSIS

MRS. R SWETHA SRI , D.SHRAVYA , DR.K.BHAVYA SRI

Electromagnetic lens- focused electron beam, electron gun, secondary electron, backscattered electron, bombardment of electrons, electron beam incident.

Electron probe microanalysis and microscopy is a widely used modern analytical technique primarily for quantifying chemical compositions of solid materials and for mapping or imaging elemental distributions or surface morphology of samples at micrometer or nanometer-scale. It is also known as electron micro probe analyser. The method is non-destructive and utilizes characteristic X-rays excited by an electron beam incident on a flat surface of sample. This technique uses an electromagnetic lens-focused electron beam, generated from an electron gun, to bombard a sample. When electron beam interacts with the sample, signals such as secondary electron, backscattered electron and characteristic X-rays are generated from the interaction volume. Characteristic X-rays are produced by inelastic collisions of the incident electrons with electrons in the inner shell of atoms in the sample. When an inner electron is ejected from its orbit, it leaves a vacancy which is filled by a higher-shell electron dropping into the vacancy. The higher-shell electron sheds energy in the form of an x-ray, which is characteristic of the particular element. These signals are then examined by detectors to acquire chemical and imaging information of the sample. An electron probe is capable of analysing almost all elements (from Be to U) with a spatial resolution at or below micrometer scale and a detection limit down to a few ppm.

Volume 5 Issue 3, March-2020

Pages : 167 - 178