EPMA is an instrument used for analytical techniques by using a focused electron beam over a polished surface. The generated characteristic X-ray with specific energy is compared with the energy of standard to determine the concentration of elements. It is similar to a
scanning electron microscope (SEM).
Application
1. U-Th-Pb dating of minerals containing non-radiogenic Pb gives age with lower accuracy.
2. Image with high spatial resolution helps in understanding zoning of mineral grain
3. The spatial distribution of a specific element can be revealed by recording a ‘map’ of the intensity of its characteristic X-rays.
4. Phase relationships and elemental partitioning between coexisting phases
5. determination of the composition of coexisting phases, from which temperatures and pressures of formation can be derived.
