Mon·May 26, 2025Monday·May 26, 2025

1. 01*

   The NEXT-100 Detector

   NEXT Collaboration: C. Adams · H. Almazán · V. Álvarez · A.I. Aranburu · L. Arazi · I.J. Arnquist · F. Auria-Luna · S. Ayet · Y. Ayyad · C.D.R. Azevedo · K. Bailey · F. Ballester and 104 other authors

   The NEXT collaboration is dedicated to the study of double beta decays of ${}^{136}$Xe using a high-pressure gas electroluminescent time projection chamber. This advanced technology combines exceptional energy resolution ($\le 1\%$ FWHM at the $Q_{\beta \beta }$ value of the neutrinoless double beta decay) and powerful topological event discrimination. Building on the achievements of the NEXT-White detector, the NEXT-100 detector started taking data at the Laboratorio Subterráneo de Canfranc (LSC) in May of 2024. Designed to operate with xenon gas at 13.5 bar, NEXT-100 consists of a time projection chamber where the energy and the spatial pattern of the ionising particles in the detector are precisely retrieved using two sensor planes (one with photo-multiplier tubes and the other with silicon photo-multipliers). The detector has been operating at stable conditions using argon and xenon gases at $\sim$4 bar and drift fields of 74 V/cm and 118 V/cm, respectively. Alpha decays from the ${}^{222}$Rn chain have been used to test and monitor the stability of the detector, showing a constant electron lifetime in the drift volume. In this paper, in addition to reporting the results of the commissioning run, we provide a detailed description of the NEXT-100 detector, describe its assembly, and present the current estimation of the radiopurity budget.

   ↳ physics.ins-detnucl-exEPJC(2026)·21 citations
2. 02*

   Measurement of cosmic muon-induced events in an HPGe detector using time-coincidence technique

   Roni Dey🇮🇳 · Dipanwita Mondal🇮🇳 · Sudipta Das🇮🇳 · Varchaswi K. S. Kashyap🇮🇳 · Bedangadas Mohanty🇮🇳

   Detailed understanding and suppression of backgrounds are among the key challenges faced by Coherent Elastic Neutrino-Nucleus Scattering (CE\ensuremath{\nu}NS) experiments. The sensitivity of these experiments is largely determined by the background levels arising from various sources. Above-ground and shallow-overburden neutrino experiments typically employ passive shielding, primarily composed of lead (Pb), to suppress environmental $\gamma$ background. However, such shielding can introduce additional backgrounds that are particularly challenging for CE\ensuremath{\nu}NS experiments. These backgrounds arise mainly from $\gamma$ and neutrons produced by cosmic muon interactions in the shielding, and their contribution can become significant depending on the amount of Pb shielding used. In the current work, we measure the yield of secondary particles originating from Pb as a result of high-energy cosmic muon interaction, using a high-purity germanium (HPGe) detector and plastic scintillators. A time-coincidence technique is used to identify and reject these secondary background events from the experimental data. The obtained mean characteristic time of these residual background events is 11 $\pm$ 4 $\mu$s, which is consistent with the Geant4-based MC simulation result of 11 $\pm$ 1 $\mu$s. The measured efficiency-corrected rate of muon-induced events in the HPGe detector is 34 $\pm$ 1 (stat.) $\pm$ 3 (sys.) day${}^{-1}$kg${}^{-1}$ within the energy range of 30 keV to 2000 keV. The yield of muon-induced secondary backgrounds in 10 cm thick Pb shielding is evaluated to be $(11\pm 1(\text{stat.})\pm 1(\text{sys.}))$ secondary events${\text{kg}}^{-1}{\mathrm{m}}^{-2}{\text{muon}}^{-1}$ at sea level.

   ↳ physics.ins-detastro-ph.IMnucl-exEur.Phys.J.Plus(2025)·0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.