The BiPo-3 detector for the measurement of ultra low natural radioactivities of thin materials
physics.ins-det
/ Authors
A. S. Barabash, A. Basharina-Freshville, E. Birdsall, S. Blondel, S. Blot, M. Bongrand, D. Boursette, V. Brudanin, J. Busto, A. J. Caffrey
and 86 more authors
S. Calvez, M. Cascella, S. Cebrián, C. Cerna, J. P Cesar, E. Chauveau, A. Chopra, T. Dafní, S. De Capua, D. Duchesneau, D. Durand, V. Egorov, G. Eurin, J. J. Evans, L. Fajt, D. Filosofov, R. Flack, X. Garrido, H. Gómez, B. Guillon, P. Guzowski, K. Holý, R. Hodák, A. Huber
/ Abstract
The BiPo-3 detector, running in the Canfranc Underground Laboratory (Laboratorio Subterráneo de Canfranc, LSC, Spain) since 2013, is a low-radioactivity detector dedicated to measuring ultra low natural radionuclide contaminations of $^{208}$Tl ($^{232}$Th chain) and $^{214}$Bi ($^{238}$U chain) in thin materials. The total sensitive surface area of the detector is 3.6 m$^2$. The detector has been developed to measure radiopurity of the selenium double $β$-decay source foils of the SuperNEMO experiment. In this paper the design and performance of the detector, and results of the background measurements in $^{208}$Tl and $^{214}$Bi, are presented, and validation of the BiPo-3 measurement with a calibrated aluminium foil is discussed. Results of the $^{208}$Tl and $^{214}$Bi activity measurements of the first enriched $^{82}$Se foils of the double $β$-decay SuperNEMO experiment are reported. The sensitivity of the BiPo-3 detector for the measurement of the SuperNEMO $^{82}$Se foils is $\mathcal{A}$($^{208}$Tl) $<2$ $μ$Bq/kg (90\% C.L.) and $\mathcal{A}$($^{214}$Bi) $<140$ $μ$Bq/kg (90\% C.L.) after 6 months of measurement.