Ultra-sensitive radioanalytical technologies for underground physics experiments P. P. Povinec 1 • L. Benedik 2 • R. Breier 1 • M. Jes ˇkovsky ´ 1 • J. Kaizer 1 • J. Kamenı ´k 3 • O. Kochetov 4 • J. Kuc ˇera 3 • P. Loaiza 5 • S. Nisi 6 • V. Palus ˇova ´ 1 • F. Piquemal 7,8 Received: 2 May 2018 Ó Akade ´miai Kiado ´, Budapest, Hungary 2018 Abstract Assessment of radioactive contamination of construction materials used in deep underground experiments has been carried out using ultra-sensitive analytical methods such as radiometrics, inductively coupled plasma mass spectrometry (ICPMS), accelerator mass spectrometry (AMS), and neutron activation analysis. The lowest detection limits, \ 1 nBq g -1 , has been obtained with ICPMS and AMS techniques. Keywords Underground experiments Á Radiopurity measurements Á 238 U and 232 Th decay series Á AMS Á ICPMS Á HPGe gamma-spectrometry Introduction Ultra-sensitive radioanalytical technologies have been playing an essential role in assessment of radioactive contamination of construction materials used in deep underground physics experiments, such as investigations of rare nuclear processes and decays—neutrinoless double beta-decay experiments (e.g. SuperNEMO [1], GERDA [2], MAJORANA [3], LEGEND [4]), neutrino physics experiments (e.g. BOREXINO [5]), as well as in searches for dark matter (e.g. in CRESST [6], EURECA [7]). Double beta-decay experiments represent the most fre- quently carried out underground experiments. Already 12 isotopes have been identified with half-lives ranging from 10 19 to 10 24 y, including 48 Ca, 82 Se, 96 Zr, 100 Mo, 116 Cd, 130 Te and 150 Nd which were studied in the NEMO-3 experiment ([8]). The double beta-decay is a second order process which is allowed by the Standard Model. As this is a very complex topic, we shall focus here specifically on the SuperNEMO experiment, which will search for neu- trinoless double beta-decay of 82 Se, and its first module (called Demonstrator) is presently under construction in Modane underground laboratory [1, 9]. The search for neutrinoless double beta-decay represents a new challenge for underground experiments. If con- firmed, the process would violate the lepton number con- servation, requiring a Majorana neutrino (to be identical with its antineutrino), and giving unique information on the neutrino mass hierarchy. Neutrinoless double beta-decay experiments represent thus a new physics behind the Standard Model. With more than ten experiments which have been going on in several underground laboratories, only upper half-live limits in the 10 24 –10 26 y range have been reported till now (e.g. [2, 8]). The aim of the present paper has been to review the sources of background in deep underground experiments and to discuss ultra-sensitive technologies for assessment of radioactivity of construction materials. At great depths & P. P. Povinec povinec@fmph.uniba.sk 1 Centre for Nuclear and Accelerator Technologies (CENTA), Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia 2 Josef Stefan Institute, Ljubljana, Slovenia 3 Nuclear Physics Institute CAS, Husinec-R ˇ ez ˇ, Czech Republic 4 Joint Institute for Nuclear Research, Dubna, Russia 5 LAL, Universite ´ Paris-Sud, CNRS/IN2P3, Universite ´ Paris- Saclay, Orsay, France 6 Laboratori Nazionali del Gran Sasso, INFN, Assergi, Italy 7 Laboratoire Souterrain de Modane, Modane, France 8 CNRS/IN2P3, CENBG, Universite ´ de Bordeaux, Gradignan, France 123 Journal of Radioanalytical and Nuclear Chemistry https://doi.org/10.1007/s10967-018-6105-9