²¹⁰Pb measurements at the André E. Lalonde AMS Laboratory: Potential for the radioassay of materials used in rare event search detectors

²¹⁰Pb (𝑇1∕2=22.2 y) is an important source of background in rare event searches, such as neutrinoless double-𝛽 decay and dark matter direct detection experiments. In this paper, the capabilities of the A.E. Lalonde AMS Laboratory at the University of Ottawa for ²¹⁰Pb measurements are discussed.
For fluoride targets, the blank ²¹⁰Pb/²⁰⁶Pb ratio was in the 1e-14 to 1e-13 range, but (PbF₃)- current output was lower and less stable. For oxide targets, (PbO₂)- current output showed better stability, despite a significant difference in current output for commercial PbO and processed samples, and background studies suggested a background not much higher than that of the fluoride targets. Both target materials showed, therefore, good performance for ²¹⁰Pb Accelerator Mass Spectrometry assay.
Measurements of Kapton ultra-thin films were performed. 90% C.L. upper limits for the ²¹⁰Pb specific activity in the range of 0.74–2.8 Bq/kg were established for several Kapton HN films.