Journal Article

Precision measurement of the specific activity of³⁹39 Ar in atmospheric argon with the DEAP-3600 detector

J. Sosiak, C. Hearns, V. Pesudo, A. Butcher, A. Kemp, P. Nadeau, C. Ng, B. Sur, C. J. Jillings, B. Vyas, M. Kuźniak, E. Picciau, A. Zuñiga-Reyes, J. Mason, B. Broerman, S. Choudhary, B. Jigmeddorj, P. Giampa, B. Beltran, M. Cárdenas-Montes, M. Hamstra, B. Smith, S. Seth, J. Bonatt, S. Langrock, J. Anstey, S. Pal, P. García Abia, D. Goeldi, J. Lock, G. Fiorillo, S. Haskins, A. L. Hallin, M. Stringer, T. McElroy, V. Strickland, P. Di Stefano, P.-A. Amaudruz, N. J. T. Smith, J. B. Ruhland, S. Westerdale, M. Baldwin, M. Batygov, A. B. McDonald, D. Papi, J. Soukup, Y. Chen, F. La Zia, J. Walding, P. Adhikari, T. Sonley, T. R. Pollmann, D. R. Grant, S. Florian, P. DelGobbo, R. Gagnon, J. Monroe, P. M. Burghardt, S. Daugherty, C. Nantais, M. Walczak, J. Willis, S. Viel, M. Ward, P. J. Harvey, G. Kaur, J. DiGioseffo, J. Tang, M. G. Boulay, F. Rad, F. G. Schuckman II, V. Shalamova, M. Cadeddu, D. Gallacher, S. J. M. Peeters, B. T. Cleveland, S. Garg, P. Majewski, K. Graham, D. J. Auty, T. Hugues, J. B. McLaughlin, B. Cai, C. Stone, J. Hu, D. Cranshaw, C. Rethmeier, L. Doria, E. T. Rand, G. Dolganov, M. Alpízar-Venegas, M. Chen, N. Seeburn, J. Lidgard, M. Lissia, C. Mielnichuk, L. Lu

2023

Overview

Abstract The specific activity of theβ β decay of³⁹39 Ar in atmospheric argon is measured using the DEAP-3600 detector. DEAP-3600, located 2 km underground at SNOLAB, uses a total of (3269 ± 24) kg of liquid argon distilled from the atmosphere to search for dark matter. This detector is well-suited to measure the decay of³⁹39 Ar owing to its very low background levels. This is achieved in two ways: it uses low background construction materials; and it uses pulse-shape discrimination to differentiate between nuclear recoils and electron recoils. With 167 live-days of data, the measured specific activity at the time of atmospheric extraction is (0.964 ± 0.001_(\\textrm{stat}{}{})stat ± 0.024_(\\textrm{sys}{}{})sys ) Bq/kg_(\\textrm{atmAr}{}{})atmAr , which is consistent with results from other experiments. A cross-check analysis using different event selection criteria and a different statistical method confirms the result.

• Publisher: SpringerOpen