Observation of a Nuclear Recoil Peak at the 100 eV Scale Induced by Neutron Capture
H. Abele, G. Angloher, A. Bento, L. Canonica, F. Cappella, L. Cardani, N. Casali, R. Cerulli, A. Chalil, A. Chebboubi, I. Colantoni, Jean-Paul Crocombette, A. Cruciani, G. del Castello, M. del Gallo Roccagiovine, D. Desforge, A. Doblhammer, Éric Dumonteil, S. Dorer, A. Erhart, A. Fuss, M. Friedl, Abhijit Garai, V. M. Ghete, A. Giuliani, C. Goupy, F. Gunsing, D. Hauff, F. Jeanneau, E. Jericha, M. Kaznacheeva, A. Kinast, H. Kluck, A. Langenkämper, T. Lasserre, A. Letourneau, D. Lhuillier, O. Litaize, M. Mancuso, P. de Marcillac, S. Marnieros, T. Materna, B. Mauri, A. Mazzolari, E. Mazzucato, H. Neyrial, C. Nones, L. Oberauer, T. Ortmann, A. Ouzriat, L. Pattavina, L. Peters, F. Petricca, D. V. Poda, W. Potzel, F. Pröbst, F. Reindl, R. Rogly, M. Romagnoni, J. Rothe, N. Schermer, J. Schieck, S. Schönert, C. Schwertner, L. Scola, O. Sérot, G. Soum-Sidikov, L. Stodolsky, Du Toit Strauss, M. Tamisari, L. Thulliez, C. Tomei, M. Vignati, M. Vivier, V. Wagner, A. Wex
Abstract
Coherent elastic neutrino-nucleus scattering and low-mass dark matter detectors rely crucially on the understanding of their response to nuclear recoils. We report the first observation of a nuclear recoil peak at around 112 eV induced by neutron capture. The measurement was performed with a CaWO_{4} cryogenic detector from the NUCLEUS experiment exposed to a ^{252}Cf source placed in a compact moderator. We identify the expected peak structure from the single-γ de-excitation of ^{183}W with 3σ and its origin by neutron capture with 6σ significance. This result demonstrates a new method for precise, in situ, and nonintrusive calibration of low-threshold experiments.