Abstract
The BiPo-3 detector, running at the Canfranc Underground Laboratory (LaboratorioSubterraneo de Canfranc, LSC, Spain) since 2013, is a low-radioactivity detector dedicated to measuring ultra low natural radionuclide contaminations of Tl-208 (Th-232 chain) and Bi-214 (U-238 chain) in thin materials. The total sensitive surface area of the detector is 3.6m(2).
The detector has been developed to measure the radiopurity of the selenium double fi - decay source foils of the SuperNEMO experiment. In this paper the design and performance of the detector, and results of the background measurements in 208Tl and 214Bi, are presented, and the validation of the BiPo- 3 measurement with a calibrated aluminium foil is discussed.
Results of the 208Tl and 214Bi activity measurements of the first enriched 82Se foils of the double fi - decay SuperNEMO experiment are reported. The sensitivity of the BiPo- 3 detector for the measurement of the SuperNEMO 82Se foils is A(Tl-208) < 2 mu Bq/kg (90% C.
L.) and A(Bi-214) < 140 mu Bq/kg (90% C. L.) after 6 months of measurement.