European Physical Journal C: Particles and Fields (2019-07-01)

Background model of the CUPID-0 experiment

  • O. Azzolini,
  • J. W. Beeman,
  • F. Bellini,
  • M. Beretta,
  • M. Biassoni,
  • C. Brofferio,
  • C. Bucci,
  • S. Capelli,
  • L. Cardani,
  • P. Carniti,
  • N. Casali,
  • D. Chiesa,
  • M. Clemenza,
  • O. Cremonesi,
  • A. Cruciani,
  • I. Dafinei,
  • S. Di Domizio,
  • F. Ferroni,
  • L. Gironi,
  • A. Giuliani,
  • P. Gorla,
  • C. Gotti,
  • G. Keppel,
  • M. Martinez,
  • S. Nagorny,
  • M. Nastasi,
  • S. Nisi,
  • C. Nones,
  • D. Orlandi,
  • L. Pagnanini,
  • M. Pallavicini,
  • L. Pattavina,
  • M. Pavan,
  • G. Pessina,
  • V. Pettinacci,
  • S. Pirro,
  • S. Pozzi,
  • E. Previtali,
  • A. Puiu,
  • C. Rusconi,
  • K. Schäffner,
  • C. Tomei,
  • M. Vignati,
  • A. Zolotarova

DOI
https://doi.org/10.1140/epjc/s10052-019-7078-8
Journal volume & issue
Vol. 79, no. 7
pp. 1 – 16

Abstract

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Abstract CUPID-0 is the first large mass array of enriched Zn$$^{82}$$ 82 Se scintillating low temperature calorimeters, operated at LNGS since 2017. During its first scientific runs, CUPID-0 collected an exposure of 9.95 kg year. Thanks to the excellent rejection of $$\alpha $$ α particles, we attained the lowest background ever measured with thermal detectors in the energy region where we search for the signature of $$^{82}\hbox {Se}$$ 82Se neutrinoless double beta decay. In this work we develop a model to reconstruct the CUPID-0 background over the whole energy range of experimental data. We identify the background sources exploiting their distinctive signatures and we assess their extremely low contribution [down to $$\sim 10^{-4}$$ ∼10-4 counts/(keV kg year)] in the region of interest for $$^{82}\hbox {Se}$$ 82Se neutrinoless double beta decay search. This result represents a crucial step towards the comprehension of the background in experiments based on scintillating calorimeters and in next generation projects such as CUPID.