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A variety of commonly available household and industrial ceramic items and some specialty glass materials were assayed by alpha pulse counting and ion chamber voltage measurements for radioactivity concentrations. Identification of radionuclides in some of the items was performed by gamma spectroscopy.
The samples included tableware, construction tiles and decorative tiles, figurines, and other products with a clay based composition. The concentrations of radioactivity ranged from near background to about four orders of magnitude higher.
Almost every nuclide identification test demonstrated some radioactivity content from one or more of the naturally occurring radionuclide series of thorium or uranium. The glazes seemed to contribute most of the activity, although a sample of unglazed pottery greenware showed some activity. Samples of glazing paints and samples of deliberately doped glass from the World War II era were included in the test, as was a section of foam filled poster board.
A glass disc with known Th radioactivity concentration was cast for use as a calibration source. The results from the two assay methods are compared, and a projection of sensitivity from larger electret ion chamber devices is presented. Keywords: alpha, ceramics, electret ion chamber, glazes, radioactivity, scintillation counter, thorium, uranium. The need for a large-area, low-intensity alpha test source for large face area ion chambers triggered memories: first, site and area measurements with sensitive radiation monitors at the National Institute of Standards and Technology NIST and its predecessor agency, the National Bureau of Standards NBS had indicated that the general radiation level was higher in an area lined with glazed ceramic tile than in areas lined with wallboard, cinder block, or other construction materials; and, second, that some dinnerware, e.
