[i¦lek‚trän ‚prōb ¦eks‚rā ‚mī·krō·ə′nal·ə·səs] (analytical chemistry) An analytical technique that uses a narrow electron beam, usually with a diameter less than 1 millimeter, focused on a solid specimen to excite an x-ray spectrum that provides qualitative and quantitative information characteristic of the elements in the sample. Abbreviated EPXMA.AcronymsSeeEPXMA