Electron Microprobe Laboratory




The Electron Microprobe Laboratory is located in the Research Resources Center of the Science and Engineering South Building and is dedicated to microanalysis of solid materials. The instrument is a JEOL JXA-733, recently upgraded with a new operating system by Advanced Microbeam. Using Wavelength Dispersive Spectrometry (WDS), the instrument can be used to quantitatively analyze elemental compositions of all elements from boron through carbon, nitrogen, oxygen to uranium on material surfaces.

Imaging and analytical software enables users to determine the composition of catalysts, the migration rates for metals through ceramics, the intercalation of materials into implants and exact "spot" compositions on heterogeneous mineral grains.

WDS is an X-ray technique that utilizes a 1-µm electron beam that illuminates the specimen mounted in an evacuated chamber. This beam knocks electrons out of their orbits causing X-rays, with characteristic patterns for each element. The large number of overlapping X-ray energy levels created by the specimen's elements are diffracted into discrete wavelengths by a crystal mirror so that only discrete wavelengths are counted by the X-ray detectors. The JXA-733 instrument utilizes a tungsten electron source and has five WDS crystal spectrometers capable of analyzing all elements between boron and uranium. At present three WDS are operational with five types of crystal. The instrument also incorporates a Noran 5500 EDX system with a Be window detector. The imaging resolution of the microprobe is 100 nm and the magnification range 20x to 360,000x. The instrument is equipped with secondary and backscattered electron detectors and a transmitted light optical system.