One was developed by James Hillier and Richard Baker at RCA. In the early 1940s, they built an electron microprobe, combining an electron microscope and an energy loss spectrometer.

Who invented the electron microscope and when?

Ernst Ruska, a German electrical engineer, is credited with inventing the electron microscope. The earliest electron microscope was developed in 1931, and the first commercial, mass-produced instrument became available in 1939.

What is an electron microprobe used for?

An electron probe micro-analyzer is a microbeam instrument used primarily for the in situ non-destructive chemical analysis of minute solid samples. EPMA is also informally called an electron microprobe, or just probe. It is fundamentally the same as an SEM, with the added capability of chemical analysis.