A first test of CUPID prototypal light detectors with NTD-Ge sensors in a pulse-tube cryostat
Authors: Alfonso K. , Armatol A. , Augier C. , Avignone F.T. , Azzolini O. , Balata M. , Barabash A.S. , Bari G. , Barresi A. , Baudin D. , Bellini F. , Benato G. , Berest V. , Beretta M. , Bettelli M. , Biassoni M. , Billard J. , Boldrini V. , Branca A. , Brofferio C. , Bucci C. , Camilleri J. , Campani A. , Capelli C. , Capelli S. , Cappelli L. , Cardani L. , Carniti P. , Casali N. , Celi E. , Chang C. , Chiesa D. , Clemenza M. , Colantoni I. , Copello S. , Craft E. , Cremonesi O. , Creswick R.J. , Cruciani A. , D'Addabbo A. , D'Imperio G. , Dabagov S. , Dafinei I. , Danevich F.A. , De Jesus M. , de Marcillac P. , Dell'Oro S. , Di Domizio S. , Di Lorenzo S. , Dixon T. , Dompé V. , Drobizhev A. , Dumoulin L. , Fantini G. , Faverzani M. , Ferri E. , Ferri F. , Ferroni F. , Figueroa-Feliciano E. , Foggetta L. , Formaggio J. , Franceschi A. , Fu C. , Fu S. , Fujikawa B.K. , Gallas A. , Gascon J. , Ghislandi S. , Giachero A. , Gianvecchio A. , Girola M. , Gironi L. , Giuliani A. , Gorla P. , Gotti C. , Grant C. , Gras P. , Guillaumon P.V. , Gutierrez T.D. , Han K. , Hansen E.V. , Heeger K.M. , Helis D.L. , Huang H.Z. , Imbert L. , Johnston J. , Juillard A. , Karapetrov G. , Keppel G. , Khalife H. , Kobychev V.V. , Kolomensky Yu.G. , Konovalov S.I. , Kowalski R. , Langford T. , Lefevre M. , Liu R. , Liu Y. , Loaiza P. , Ma L. , Madhukuttan M. , Mancarella F. , Marini L. , Marnieros S. , Martinez M. , Maruyama R.H. , Mas Ph. , Mayer D. , Mazzitelli G. , Mei Y. , Milana S. , Morganti S. , Napolitano T. , Nastasi M. , Nikkel J. , Nisi S. , Nones C. , Norman E.B. , Novosad V. , Nutini I. , O'Donnell T. , Olivieri E. , Olmi M. , Ouellet J.L. , Pagan S. , Pagliarone C. , Pagnanini L. , Pattavina L. , Pavan M. , Peng H. , Pessina G. , Pettinacci V. , Pira C. , Pirro S. , Poda D.V. , Polischuk O.G. , Ponce I. , Pozzi S. , Previtali E. , Puiu A. , Quitadamo S. , Ressa A. , Rizzoli R. , Rosenfeld C. , Rosier P. , Scarpaci J.A. , Schmidt B. , Sharma V. , Shlegel V.N. , Singh V. , Sisti M. , Slocum P. , Speller D. , Surukuchi P.T. , Taffarello L. , Tomei C. , Torres J.A. , Tretyak V.I. , Tsymbaliuk A. , Velazquez M. , Vetter K.J. , Wagaarachchi S.L. , Wang G. , Wang L. , Wang R. , Welliver B. , Wilson J. , Wilson K. , Winslow L.A. , Xue M. , Yan L. , Yang J. , Yefremenko V. , Umatov V.I. , Zarytskyy M.M. , Zhang J. , Zolotarova A. , Zucchelli S. 
Published: June 2023

Abstract
CUPID is a next-generation bolometric experiment aiming at
searching for neutrinoless double-beta decay with ∼250 kg of
isotopic mass of 100Mo. It will operate at ∼10 mK in a
cryostat currently hosting a similar-scale bolometric array for the
CUORE experiment at the Gran Sasso National Laboratory
(Italy). CUPID will be based on large-volume scintillating
bolometers consisting of 100Mo-enriched Li2MoO4 crystals,
facing thin Ge-wafer-based bolometric light detectors. In the CUPID
design, the detector structure is novel and needs to be
validated. In particular, the CUORE cryostat presents a high level
of mechanical vibrations due to the use of pulse tubes and the
effect of vibrations on the detector performance must be
investigated. In this paper we report the first test of the
CUPID-design bolometric light detectors with NTD-Ge sensors in a
dilution refrigerator equipped with a pulse tube in an above-ground
lab. Light detectors are characterized in terms of sensitivity,
energy resolution, pulse time constants, and noise power
spectrum. Despite the challenging noisy environment due to
pulse-tube-induced vibrations, we demonstrate that all the four
tested light detectors comply with the CUPID goal in terms of
intrinsic energy resolution of 100 eV RMS baseline noise. Indeed,
we have measured 70–90 eV RMS for the four devices, which show an
excellent reproducibility. We have also obtained high energy
resolutions at the 356 keV line from a 133Ba source, as good
as Ge semiconductor γ detectors in this energy range.