Discovery of underground argon with low level of radioactive Ar-39 and possible applications to WIMP dark matter detectors

Acosta Kane, D.; Acciarri, R.; Amaize, O.; Antonello, M.; Baibussinov, B.; Ceolin, M. B.; Ballentine, C. J.; Bansal, R.; Basgall, L.; Bazarko, A.; Benetti, P.; Benziger, J.; Burgers, A.; Calaprice, F.; Calligarich, E.; Cambiaghi, M.; Canci, N.; Carbonara, F.; Cassidy, M.; Cavanna, F.; Centro, S.; Chavarria, A.; Cheng, D.; Cocco, A. G.; Collon, P.; Dalnoki Veress, F.; Haas, E. d.; Pompeo, F. D.; Fiorillo, Giuliana; Fitch, F.; Gallo, V.; Galbiati, C.; Gaull, M.; Gazzana, S.; Grandi, L.; Goretti, A.; Highfill, R.; Highfill, T.; Hohman, T.; Ianni, A.; Ianni, A.; Lacava, A.; Laubenstein, M.; Lee, H. Y.; Leung, M.; Loer, B.; Loosli, H. H.; Lyons, B.; Marks, D.; Mccarty, K.; Meng, G.; Montanari, C.; Mukhopadhyay, S.; Nelson, A.; Palamara, O.; Pandola, L.; Pietropaolo, F.; Pivonka, T.; Pocar, A.; Purtschert, R.; Rappoldi, A.; Raselli, G.; Resnati, F.; Robertson, D.; Roncadelli, M.; Rossella, M.; Rubbia, C.; Ruderman, J.; Saldanha, R.; Schmitt, C.; Scott, R.; Segreto, E.; Shirley, A.; Szelc, A. M.; Tartaglia, R.; Tesileanu, T.; Ventura, S.; Vignoli, C.; Visnjic, C.; Vondrasek, R.; Yushkov, A.

doi:10.1016/j.nima.2007.12.032

We report oil the first measurement of Ar-39 in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of Ar-39. The ratio of 39Ar to stable argon was measured to be <= 4 x 10(-17) (84% C.L.), less than 5% the value in atmospheric argon (Ar-39/Ar = 8 x 10(-16)). The total quantity of argon currently stored in the National Helium Reserve is estimated at 1000 tons. 39Ar represents one of the most important backgrounds in argon detectors for WIMP dark matter searches. The findings reported demonstrate the possibility of constructing large multi-ton argon detectors with low radioactivity suitable for WIMP dark matter searches. (C) 2007 Elsevier B.V. All rights reserved.

Discovery of underground argon with low level of radioactive Ar-39 and possible applications to WIMP dark matter detectors / D., Acosta Kane; R., Acciarri; O., Amaize; M., Antonello; B., Baibussinov; M. B., Ceolin; C. J., Ballentine; R., Bansal; L., Basgall; A., Bazarko; P., Benetti; J., Benziger; A., Burgers; F., Calaprice; E., Calligarich; M., Cambiaghi; N., Canci; F., Carbonara; M., Cassidy; F., Cavanna; S., Centro; A., Chavarria; D., Cheng; A. G., Cocco; P., Collon; F., Dalnoki Veress; E. d., Haas; F. D., Pompeo; Fiorillo, Giuliana; F., Fitch; V., Gallo; C., Galbiati; M., Gaull; S., Gazzana; L., Grandi; A., Goretti; R., Highfill; T., Highfill; T., Hohman; A., Ianni; A., Ianni; A., Lacava; M., Laubenstein; H. Y., Lee; M., Leung; B., Loer; H. H., Loosli; B., Lyons; D., Marks; K., Mccarty; G., Meng; C., Montanari; S., Mukhopadhyay; A., Nelson; O., Palamara; L., Pandola; F., Pietropaolo; T., Pivonka; A., Pocar; R., Purtschert; A., Rappoldi; G., Raselli; F., Resnati; D., Robertson; M., Roncadelli; M., Rossella; C., Rubbia; J., Ruderman; R., Saldanha; C., Schmitt; R., Scott; E., Segreto; A., Shirley; A. M., Szelc; R., Tartaglia; T., Tesileanu; S., Ventura; C., Vignoli; C., Visnjic; R., Vondrasek; A., Yushkov. - In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT. - ISSN 0168-9002. - STAMPA. - 587:(2008), pp. 46-51. [10.1016/j.nima.2007.12.032]