Sub-keV Electron Recoil Calibration for Macroscopic Cryogenic Calorimeters using a Novel X-ray Fluorescence Source
H. Abele, G. Angloher, B. Arnold, M. Atzori Corona, A. Bento, E. Bossio, J. Burkhart, F. Cappella, M. Cappelli, N. Casali, R. Cerulli, A. Cruciani, G. Del Castello, M. del Gallo Roccagiovine, S. Dorer, A. Erhart, M. Friedl, S. Fichtinger, V. M. Ghete, M. Giammei, C. Goupy, D. Hauff, F. Jeanneau, E. Jericha, M. Kaznacheeva, A. Kinast, H. Kluck, A. Langenkämper, T. Lasserre, D. Lhuillier, M. Mancuso, R. Martin, B. Mauri, A. Mazzolari, L. McCallin, H. Neyrial, C. Nones, L. Oberauer, T. Ortmann, L. Pattavina, L. Peters, F. Petricca, W. Potzel, F. Pröbst, F. Pucci, F. Reindl, M. Romagnoni, J. Rothe, N. Schermer, J. Schieck, S. Schönert, C. Schwertner, L. Scola, G. Soum-Sidikov, L. Stodolsky, R. Strauss, M. Tamisari, R. Thalmeier, C. Tomei, M. Vignati, M. Vivier, A. Wex, K. v. Mirbach, V. Wagner
公開日: 2025/5/23
Abstract
Percent-level calibration of cryogenic macro-calorimeters with energy thresholds below 100~eV are crucial for light Dark Matter (DM) searches and reactor neutrino studies based on coherent elastic neutrino-nucleus scattering (CEvNS). This paper presents a novel calibration source based on X-ray fluorescence (XRF) of light elements. It uses a $^{55}$Fe source to irradiate a two-staged target arrangement, emitting characteristic emission lines from 677\,eV to 6.5\,keV. We demonstrate the potential of this new XRF source to calibrate a 0.75 gram CaWO$_4$ crystal of the NUCLEUS and CRAB experiments. Additionally, we introduce CryoLab, an advanced analysis tool for cryogenic detector data, featuring robust methods for data processing, calibration, and high-level analysis, implemented in MATLAB and HDF5. We also present a phenomenological model for energy resolution, which incorporates statistical contributions, systematic effects, and baseline noise, enabling a novel approach to evaluating athermal phonon collection efficiency in macro-calorimeters based on transition edge sensors (TES).