Well-characterized calibration standards for microanalytical applications are difficult to obtain, often poorly characterized, and often not homogeneous from piece to piece. In addition, many microanalytical standards are available only in very small quantities making inter-laboratory comparisons difficult. To further complicate the situation, destructive microbeam techniques such as secondary ion mass spectrometry (SIMS) and laser source mass spectrometries (LSMS) require larger quantities of material than nondestructive techniques.

The U.S. Geological Survey, Geologic Division is in the process of evaluating ways to produce relatively large quantities of well-characterized standards. We are interested in producing standards of geological materials appropriate for multiple microbeam techniques including electron probe microanalysis (EPMA), SIMS and LSMS. The microbeam standards are produced by melting powders of standards of naturally occurring materials that the USGS has previously provided as bulk analytical standards.