Recent Bremsstrahlung-based assays of 210Pb in lead and comments on current availability of low-background lead in North America

Abstract Low-background lead for radiation measurement shielding is often assayed for 210 Pb to ensure acceptable backgrounds. Samples of lead assayed with a germanium spectrometer calibrated for bremsstrahlung-based assay of 210 Pb provide a view into the 210 Pb content of commercial lead in the U.S. (other than stockpiled Doe Run lead). Results suggest that the loss of lead smelting in the U.S. has eliminated the traditional supply of “low background” lead (~30 Bq kg −1 ), and indicate current commercial supplies contain roughly an order of magnitude higher 210 Pb levels.