arXiv subjects

J. Soto-Oton

Publications and source records attributed to J. Soto-Oton.

13 recordsLinked to original sources

arXiv2026

Demonstrating topological identification capabilities of the NEXT experiment at low pressure

The NEXT-100 detector is a high-pressure xenon time projection chamber utilising electroluminescence amplification for sub-1% FWHM energy resolution and topological discrimination, two key attributes required to achieve the NEXT programme's overarching goal of detecting neutrinoless double beta decay ($0 νββ$). The detector has completed its first physics run at the Laboratorio Subterráneo de Canfranc (LSC), with xenon at a pressure of $\sim$4 bar. In this paper we report on the first validation of NEXT-100's topological performance and present the first topological analysis conducted at low pressure within the detector programme. A Monte Carlo study characterising the effects of pressure on track topology is presented, with qualitative agreement observed in data. We then demonstrate the topological discrimination capabilities for $0νββ$-like events from $^{208}$Tl decays using a cut-based method considered the 'baseline' in NEXT's topological programme, upon which all future analyses will improve. The analysis described applies a set of selection cuts before implementing a background discrimination algorithm that yields a reported signal efficiency for double-electron tracks and background acceptance for single-electron tracks of 75.6 $\pm$ 1.9 (stat.) $^{+3.4}_{-4.1}$ (syst.) % and 14.7 $\pm$ 0.4 (stat.) $^{+0.7}_{-0.8}$ (syst.) %. These results demonstrate the excellent topological discrimination capabilities of the NEXT-100 detector in line with NEXT-White, which achieved a signal efficiency and background acceptance of 71.6 $\pm$ 1.5 (stat.) $\pm$ 0.3 (syst.) % and 20.6 $\pm$ 0.4 (stat.) $\pm$ 0.3 (syst.) % respectively.

hep-ex↗

arXiv2026

Detection of scintillation light in noble gases with wavelength-shifting optical fibers

Wavelength-shifting (WLS) techniques enable particle detectors based on noble gases, whose scintillation light is predominantly emitted in the vacuum-ultraviolet. We investigate WLS fibers coated with tetraphenyl butadiene (TPB) for scintillation light detection in gaseous xenon and argon at pressures up to 8.5 bar, motivated by future high-pressure xenon time-projection chambers of the NEXT program. Two detector configurations are studied: an elongated high-pressure vessel with four PTFE panels equipped with WLS fibers read by temperature-stabilized SiPMs, and a compact box-shaped detector operated at 1 bar Xe with WLS fibers read out by PMTs. Both operate with continuous gas purification. The detector response is characterized using cosmic muons and alpha particles from a $^{241}$Am source. With the SiPM setup, we measure a light collection efficiency (LCE) of ${1.18 \pm 0.01~\mathrm{(sta.)}~^{+0.07}_{-0.09}~\mathrm{(sys.)}~\%}$ for xenon and ${1.07 \pm 0.01~\mathrm{(sta.)}~^{+0.06}_{-0.08}~\mathrm{(sys.)}~\%}$ for argon. With PMT readout, we measure a LCE of ${0.45 \pm 0.01~\mathrm{(sta.)} \pm 0.05~\mathrm{(sys.)}~\%}$ in xenon, in agreement with the SiPM result once photon detection efficiency is accounted for. Average scintillation waveforms in xenon and argon are studied to assess the time structure of the emitted light. Cosmic-muon measurements yield a mean energy required to produce a scintillation photon $45\pm7~\mathrm{(sta.)}~^{+4}_{-5}~\mathrm{(sys.)}~\mathrm{eV}$ at 1.5 bar, in agreement with the literature. The results demonstrate that TPB-coated WLS fiber systems can reliably detect scintillation light in high-pressure gaseous noble detectors, with a LCE representing an upper limit for realistic large-scale TPCs, where additional photon losses from materials and fiber attenuation are expected.

physics.ins-det↗

arXiv2026

Radon-induced backgrounds in the NEXT-100 experiment

The NEXT-100 detector at the LSC aims at the first competitive search for the \bbnonu decay using a high-pressure \Xe{136} electroluminescent time projection chamber. The first low-background run of NEXT-100 at 3.95 bar has been devoted to the measurement of the radon-induced backgrounds impacting this search. The contributions from both the internal and external airborne radon have been evaluated. The internal \Rn{222} activity is found to be (0.95$\pm$0.04(stat)$\pm$0.09(sys)) Bq/m$^3$, while no traces of \Rn{220} have been observed. Most of the \Rn{222} progeny plate-out on the surface of the cathode of the detector, leading to a rate of Rn-induced \Bi{214} of (0.97$\pm$0.05(stat)$\pm$0.10(sys)) Hz for visible energies above 400 keV. The corresponding background index in the \bbnonu region of interest is evaluated as (7.3$\pm$1.5(stat)$\pm$0.8(sys))$\times10^{-4}$ counts/(keV$\cdot$kg$\cdot$yr) after selection of the fully contained events. This background index is reduced to $\sim$4$\times10^{-5}$ counts/(keV$\cdot$kg$\cdot$yr) by applying a topological selection requiring only one double-electron-like track in the events. This value is one order of magnitude below the total radiogenic background expectation in NEXT-100. By analyzing the correlation of the airborne radon activity and the measured rate of events in NEXT-100, it is concluded that the detector operates in a virtually radon-free environment thanks to the radon abatement system of the LSC.

hep-ex↗

arXiv2026

VUV Reflectance Measurements for Materials Relevant to Argon and Xenon Experiments

Accurate knowledge of material reflectance in the vacuum ultraviolet (VUV) range is crucial for optimizing photon detection in noble gas detectors such as DUNE. Despite its importance, reflectance values for detector materials in the VUV region remain poorly characterized, with literature values showing significant variation depending on surface termination and finish. We present an angular-resolved reflectance measurement system developed at IFIC that operates in a gaseous argon atmosphere, enabling realistic measurements of detector materials under controlled conditions. The setup couples a deuterium lamp to a monochromator and employs a motorized PMT rotating around the sample to measure reflected light distributions across a wide angular range. We have characterized two key DUNE materials -- aluminum field cage profiles and stainless steel cryostat membranes -- in both the UV-VIS (300-500 nm) and VUV (128-200 nm) ranges. In the UV-VIS region, we confirm literature values of approximately 60% reflectance for aluminum and 40% for stainless steel. Preliminary VUV measurements at 45° angle of incidence yield reflectance values of 10-15% for both materials, significantly lower than their UV-VIS counterparts. The reflected light distributions exhibit a mixed character between specular and diffuse reflection. These results have direct implications for detector simulations and light yield predictions in next-generation experiments.

physics.ins-det↗

arXiv2025

High Voltage Delivery and Distribution for the NEXT-100 Time Projection Chamber

A critical element in the realization of large liquid and gas time projection chambers (TPCs) is the delivery and distribution of high voltages into and around the detector. Such experiments require of order tens of kilovolts to enable electron drift over meter-scale distances. This paper describes the design and operation of the cathode feedthrough and high voltage distribution through the field cage of the NEXT-100 experiment, an underground TPC that will search for neutrinoless double beta decay $0νββ$. The feedthrough has been demonstrated to hold pressures up to 20~bar and sustain voltages as high as -65~kV, and the TPC is operating stably at its design high voltages. The system has been realized within the constraints of a stringent radiopurity budget and is now being used to execute a suite of sensitive double beta decay analyses.

physics.ins-det↗

arXiv2025

Reconstructing neutrinoless double beta decay event kinematics in a xenon gas detector with vertex tagging

If neutrinoless double beta decay is discovered, the next natural step would be understanding the lepton number violating physics responsible for it. Several alternatives exist beyond the exchange of light neutrinos. Some of these mechanisms can be distinguished by measuring phase-space observables, namely the opening angle $\cosθ$ among the two decay electrons, and the electron energy spectra, $T_1$ and $T_2$. In this work, we study the statistical accuracy and precision in measuring these kinematic observables in a future xenon gas detector with the added capability to precisely locate the decay vertex. For realistic detector conditions (a gas pressure of 10 bar and spatial resolution of 4 mm), we find that the average $\overline{\cosθ}$ and $\overline{T_1}$ values can be reconstructed with a precision of 0.19 and 110 keV, respectively, assuming that only 10 neutrinoless double beta decay events are detected.

hep-ex↗

arXiv2024

ProtoDUNE Photon Detection System

The Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino oscillation experiment aiming to measure the oscillation parameters with an unprecedented precision that will allow determining the CP violation phase in the leptonic sector and the neutrino mass ordering. The Far Detector of DUNE will consist of four 17 kton liquid argon Time Projection Chambers (LAr-TPC). Inside a LAr-TPC, a Photon Detection System (PDS) is needed to detect the scintillation light produced by the interacting particles. The PDS signal provides the interaction time for non-beam events and improves the calorimetric reconstruction. To validate DUNE technology, two large-scale prototypes, of 750 ton of LAr each, have been constructed at CERN, ProtoDUNE-HD and ProtoDUNE-VD. The PDS of both prototypes is based on the XArapuca concept, a SiPM-based device that provides good detection efficiency covering large surfaces at a reasonable cost. This document presents the preliminary performance of the ProtoDUNE-HD Photon Detection System, which has taken data from April to November 2024.

hep-ex↗

arXiv2024

Measurement of Energy Resolution with the NEXT-White Silicon Photomultipliers

The NEXT-White detector, a high-pressure gaseous xenon time projection chamber, demonstrated the excellence of this technology for future neutrinoless double beta decay searches using photomultiplier tubes (PMTs) to measure energy and silicon photomultipliers (SiPMs) to extract topology information. This analysis uses $^{83m}\text{Kr}$ data from the NEXT-White detector to measure and understand the energy resolution that can be obtained with the SiPMs, rather than with PMTs. The energy resolution obtained of (10.9 $\pm$ 0.6) $\%$, full-width half-maximum, is slightly larger than predicted based on the photon statistics resulting from very low light detection coverage of the SiPM plane in the NEXT-White detector. The difference in the predicted and measured resolution is attributed to poor corrections, which are expected to be improved with larger statistics. Furthermore, the noise of the SiPMs is shown to not be a dominant factor in the energy resolution and may be negligible when noise subtraction is applied appropriately, for high-energy events or larger SiPM coverage detectors. These results, which are extrapolated to estimate the response of large coverage SiPM planes, are promising for the development of future, SiPM-only, readout planes that can offer imaging and achieve similar energy resolution to that previously demonstrated with PMTs.

hep-ex↗

arXiv2021

Impact of xenon doping in the scintillation light in a large liquid-argon TPC

The use of xenon-doped liquid argon is a promising alternative for large pure liquid-argon TPCs. Not only xenon-doped liquid argon enhances the light production, mitigating the possible suppression due to impurities, but also it increases the wavelength of the scintillation light, enlarging the effective Rayleigh scattering length and improving the detection uniformity. ProtoDUNE Dual-Phase is a 300-ton active volume LAr TPC, a prototype for the Deep Underground Neutrino Experiment (DUNE), a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual-Phase took cosmic muon data at CERN with pure liquid argon and with xenon-doped liquid argon for over a year. The impact of the presence of xenon in the scintillation light and its comparison with the pure liquid argon data will be presented. These results are of interest to any future large LAr TPCs.

physics.ins-det↗

arXiv2021

ProtoDUNE-DP Light Acquisition and Calibration Software

ProtoDUNE-DP is a 6x6x6 m3 liquid argon time-projection-chamber operated at the CERN Neutrino Platform in 2019-2020 as a prototype of the Dual Phase concept for the DUNE Far Detector. The Photon Detection System (PDS) is based on 36 8-inch photo-multiplier tubes (PMTs) and allows triggering on the scintillation light signals produced by cosmic rays and other charged particles traversing the detector. The acquisition and calibration software specifically developed for the ProtoDUNE-DP PDS is described in this paper. This software controls the high-voltage power supplies, the calibration system, and the PDS DAQ. It has been developed with Qt Creator, and features different operation modes, and a graphical user interface. This software has already been validated and used during the ProtoDUNE-DP operation.

physics.ins-det↗

arXiv2019

Light Detection in DUNE Dual-Phase

DUNE will be an underground neutrino oscillation experiment that will perform precision measurements of the PMNS mixing parameters, determine unambiguously the mass ordering and discover leptonic CP violation. It also comprises a rich non-accelerator physics program as the detection of supernova neutrinos, nucleon decay and BSM physics. One of the modules of the DUNE is proposed to be Dual-Phase LArTPC. Inside this module, a light detection system (LDS) is being designed, consisting on an array of photomultiplier tubes and a calibration system based on optical fibers. To fulfil the physics program, the LDS is aimed to comply with certain physics requirements. Those are to provide a detection efficiency of more than 90% for a Supernova Burst within the Milky Way and an event time reconstruction efficiency of more than 90% with a signal purity of more than 90% across the active volume for proton decay event candidates. The present document summarizes the status of the simulation studies of the light detection in DUNE Dual-Phase, and the expected performance of the LDS, that will be part of the forthcoming Technical Design Report of DUNE.

physics.ins-det↗

arXiv2019

A Light Calibration System for the ProtoDUNE-DP Detector

A LED-based fiber calibration system for the ProtoDUNE-Dual Phase (DP) photon detection system (PDS) has been designed and validated. ProtoDUNE-DP is a 6x6x6 m3 liquid argon time-projection-chamber currently being installed at the Neutrino Platform at CERN. The PDS is based on 36 8-inch photomultiplier tubes (PMTs) and will allow triggering on cosmic rays. The system serves as prototype for the PDS of the final DUNE DP far detector in which the PDS also has the function to allow the 3D event reconstruction on non-beam physics. For this purpose an equalized PMT response is desirable to allow using the same threshold definition for all PMT groups, simplifying the determination of the trigger efficiency. The light calibration system described in this paper is developed to provide this and to monitor the PMT performance in-situ.

physics.ins-det↗

arXiv2018

Cryogenic R5912-20Mod Photomultiplier Tube Characterization for the ProtoDUNE Dual Phase Detector

The Deep Underground Neutrino Experiment (DUNE) is a dual-site experiment for long baseline neutrino oscillation studies, and for neutrino astrophysics and nucleon decay searches. The far detector is a 40-kton underground liquid argon time-projection-chamber (LAr TPC), in which the photon detector system adds precise timing capabilities. The ProtoDUNE dual phase detector will consist of a 6x6x6 m^3 LAr TPC to be operated at the CERN Neutrino Platform and the photon detection system will be formed by 8-inch cryogenic photomultipliers from Hamamatsu. The PMT model (R5912-20Mod) performance at cryogenic temperature is studied including dark current, gain, and linearity with the light intensity and pulse rate. In addition, the PMT base design is validated. At cold, a decrease of the PMT amplification, or fatigue effect, is measured as the PMT output current increases, either, due to high gain, light intensity or rate. Also, the characterisation results of the 40 photomultipliers to be used in ProtoDUNE dual phase are presented.

physics.ins-det↗