The Electron Probe MicroAnalyzer (EPMA), also known as an electron microprobe, is an instrument that is capable of measuring the chemical composition of small volumes of solid substances. Commercial microprobes were first available in the mid to late 1950s by the Compagnie des Applications Mécaniques et Electroniques au Cinéma et à l’Atomistique (CAMECA) and the Applied Research Laboratories (ARL).
UCLA’s association with the electron microprobe began in 1963/1964 when the then Department of Geology obtained an early model ARL “EMX” microprobe. This unit was purchased using departmental building funds and a small NSF instrument grant to W. Gery Ernst. In 1969, Ernst hired Bob Jones to manage the lab. In 1976, the EMX was replaced with an ARL “SEQM” microprobe. Subsequently, a third-generation instrument became operational in 1984 when the then Department of Earth and Spaces Sciences purchased a CAMECA “Camebax-microbeam”. In 1995, Frank Kyte took over the day-to-day operations of the lab, as Bob Jones had left a few years previous.
The current microprobe was acquired in 2002 when the then Department of Earth and Planetary Sciences obtained a Japan Electron Optics Laboratory (JEOL) “JXA-8200 Superprobe”. This microprobe, along with a twin at Caltech, were JEOL’s prototype for this series of instrumentation. It was purchased through a collective grant from NSF, NASA and UCLA (PI: Craig E. Manning; Co-PIs: Frank Kyte, Paul Warren and John Wasson). In 2013, Rosario Esposito became the lab manager until his departure in 2020.
Today, the JXA-8200 Superprobe is housed within the Department of Earth, Planetary and Space Sciences. It is furnished with 5 Wavelength Dispersive X-ray Spectrometers (WDS) and one Energy Dispersive X-ray Spectrometer (EDS). The WDS is equipped with 12 diffracting crystals to include capabilities for the analysis of light elements (Z<9). Brian Damiata is the current lab manager.