arXiv subjects

Y. Mei

Publications and source records attributed to Y. Mei.

At least 19 recordsLinked to original sources

arXiv2026

Ton-scale Xenon Gas TPC for $0\nu\beta\beta$ Search at Atmospheric Pressure

We explore aspects of an unorthodox ton-scale xenon gas time projection chamber detector operated at normal temperature and pressure (NTP), designed for $0\nu\beta\beta$ discovery at $\sim10^{27}$ year sensitivity. At fixed active mass, a greater transparency to $\gamma$-ray backgrounds and better track clarity exists at NTP relative to higher density. Operation at NTP also alleviates difficulties with pressure containment and significantly reduces HV requirements. With metre-scale electron tracks at a few MeV, event topology can be used to efficiently reject the copious $\gamma$-ray backgrounds by factors ranging from 550--1200, largely compensating for the greater surface area of the detector. Event topology is captured from anode plane signals combined with sensing the secondary ion component arriving at the cathode plane. A molecular gas additive limits diffusion of the secondary electron tracks to below a cm and provides stable proportional avalanche gain. An energy resolution $\delta$E/E $\leq$ 1\% FWHM seems possible. A 100 kg scale demonstrator for this detector technology could lead directly to a ton-scale search.

physics.ins-det↗

arXiv2026

DC Cryogenic Modeling of Open-Source SkyWater 130 nm MOSFETs at 77 K Using BSIM4

Cryogenic applications in high-energy physics (HEP) demand reliable, low-power CMOS electronics capable of operating at liquid nitrogen temperatures (77 K). The open-source SkyWater 130 nm (SKY130) CMOS process has previously been shown to operate at temperatures as low as 4 K making it a promising candidate for HEP applications. In this work, we characterize and model SKY130 low-threshold voltage transistors at 77 K, which is a temperature commonly used in modeling applications for liquid argon detectors. DC characteristic measurements were performed at both room temperature and liquid nitrogen temperature. We created a cryogenic modeling approach to produce a SPICE-compatible, isothermal BSIM4-based model for select transistor sizes at 77 K. The resulting model agrees with data at 77 K with an average error on the order of 20% (relative RMS) and shows no dependence on drain voltage. Due to the open-source nature of SKY130, we have made our models publicly available on Github. We hope this work will continue the trend for democratizing circuit design at cryogenic temperatures in high-energy physics by enabling open access to accurate CMOS device models at 77 K.

cond-mat.mes-hall↗

arXiv2025

Optimal operating parameters for next-generation xenon gas time projection chambers

The next-generation of $0\nu\beta\beta$ searches are targeting half-life sensitivities towards 10$^{27}$--10$^{28}$ years. Gaseous xenon time projection chamber (GXeTPC) detectors may be able to meet this challenge due to their excellent energy resolution and background rejection power through event visualization. This paper explores how the design choices of a next-generation GXeTPC time projection chamber can impact the overall performance of the experiment. We study the performance of systems using xenon enriched in the isotope $^{136}$Xe or natural xenon, focusing on scenarios that incorporate one tonne of $^{136}$Xe isotope. The detector size, copper shielding mass, energy resolution, density and corresponding levels of diffusion are surveyed to evaluate the overall performance dependencies on these parameters. A detector optimized for using enriched xenon is preferred over natural, due primarily to a factor of 10 lower background rate driven by the large intrinsic backgrounds introduced by the copper shielding used in the detector. The performance of three types of gas TPC technologies was also explored based on different gas additives used to reduce diffusion to different levels. For all TPC technologies, we find background rates of a fraction of a count per tonne year in the region of interest are achievable. These performance levels are contingent on suitable energy resolution and event position placement in the drift direction being achieved for the specific detector technology. Performance for enriched xenon TPCs varies mildly with pressure in the range 5 to 25 bars, reaching background levels below 0.2 events/tonne-year. Performance at one bar is worse by approximately a factor of four. When considerations for the construction of the detector in addition to the selection performance are included, there may be no clearly optimum pressure.

physics.ins-det↗

arXiv2025

End-to-End Data Analysis Methods for the CUORE Experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) experiment set the most stringent limit on the neutrinoless double-beta ($0\nu\beta\beta$) decay half-life of $^{130}$Te with 2 ton yr TeO$_2$ analyzed exposure. In addition to $0\nu\beta\beta$ decay, the CUORE detector -- a ton-scale array of nearly 1000 cryogenic calorimeters operating at $\sim$10 mK -- is capable of searching for other rare decays and interactions over a broad energy range. For our searches, we leverage the available information of each calorimeter by performing its optimization, data acquisition, and analysis independently. We describe the analysis tools and methods developed for CUORE and their application to build high-quality datasets for numerous physics searches. In particular, we describe in detail our evaluation of the energy-dependent detector response and signal efficiency used in the most recent search for $0\nu\beta\beta$ decay.

nucl-ex↗

arXiv2025

Opportunities and challenges to study solar neutrinos with a Q-Pix pixel readout

The study of solar neutrinos presents significant opportunities in astrophysics, nuclear physics, and particle physics. However, the low-energy nature of these neutrinos introduces considerable challenges to isolate them from background events, requiring detectors with low-energy threshold, high spatial and energy resolutions, and low data rate. We present the study of solar neutrinos with a kiloton-scale liquid argon detector located underground, instrumented with a pixel readout using the Q-Pix technology. We explore the potential of using volume fiducialization, directional topological information, light signal coincidence and pulse-shape discrimination to enhance solar neutrino sensitivity. We find that discriminating neutrino signals below 5 MeV is very difficult. However, we show that these methods are useful for the detection of solar neutrinos when external backgrounds are sufficiently understood and when the detector is built using low-background techniques. When building a workable background model for this study, we identify {\gamma} background from the cavern walls and from capture of {\alpha} particles in radon decay chains as both critical to solar neutrino sensitivity and significantly underconstrained by existing measurements. Finally, we highlight that the main advantage of the use of Q-Pix for solar neutrino studies lies in its ability to enable the continuous readout of all low-energy events with minimal data rates and manageable storage for further offline analyses.

hep-ex↗

arXiv2025

Exploring the keV-scale physics potential of CUORE

We present the analysis techniques developed to explore the keV-scale energy region of the CUORE experiment, based on more than 2 tonne yr of data collected over 5 years. By prioritizing a stricter selection over a larger exposure, we are able to optimize data selection for thresholds at 10 keV and 3 keV with 691 kg yr and 11 kg yr of data, respectively. We study how the performance varies among the 988-detector array with different detector characteristics and data taking conditions. We achieve an average baseline resolution of 2.54 $\pm$ 0.14 keV FWHM and 1.18 $\pm$ 0.02 keV FWHM for the data selection at 10 keV and 3 keV, respectively. The analysis methods employed reduce the overall background by about an order of magnitude, reaching 2.06 $\pm$ 0.05 counts/(keV kg days) and 16 $\pm$ 2 counts/(keV kg days) at the thresholds of 10 keV and 3 keV. We evaluate for the first time the near-threshold reconstruction efficiencies of the CUORE experiment, and find these to be 26 $\pm$ 4 \% and 50 $\pm$ 2 \% at 3 keV and 10 keV, respectively. This analysis provides crucial insights into rare decay studies, new physics searches, and keV-scale background modeling with CUORE. We demonstrate that tonne-scale cryogenic calorimeters can operate across a wide energy range, from keV to MeV, establishing their scalability as versatile detectors for rare event and dark matter physics. These findings also inform the optimization of future large mass cryogenic calorimeters to enhance the sensitivity to low-energy phenomena.

hep-ex↗

arXiv2025

The detection of marine microseismic activity with the CUORE tonne-scale cryogenic experiment

Vibrations from experimental setups and the environment are a persistent source of noise for low-temperature calorimeters searching for rare events, including neutrinoless double beta ($0\nu\beta\beta$) decay or dark matter interactions. Such noise can significantly limit experimental sensitivity to the physics case under investigation. Here we report the first detection of marine microseismic vibrations using mK-scale calorimeters. This study employs a multi-device analysis correlating data from CUORE, the leading experiment in the search for $0\nu\beta\beta$ decay with mK-scale calorimeters and the Copernicus Earth Observation program, revealing the seasonal impact of Mediterranean Sea activity on CUORE's energy thresholds, resolution, and sensitivity over four years. The detection of marine microseisms underscores the need to address faint environmental noise in ultra-sensitive experiments. Understanding how such noise couples to the detector and developing mitigation strategies is essential for next-generation experiments. We demonstrate one such strategy: a noise decorrelation algorithm implemented in CUORE using auxiliary sensors, which reduces vibrational noise and improves detector performance. Enhancing sensitivity to $0\nu\beta\beta$ decay and to rare events with low-energy signatures requires identifying unresolved noise sources, advancing noise reduction methods, and improving vibration suppression systems, all of which inform the design of next-generation rare event experiments.

physics.ins-det↗

arXiv2025

Half-life and precision shape measurement of 2{\nu}{\beta}{\beta} decay of $^{130}$Te

We present a new measurement of the 2nbb half-life of 130Te (T1/2) using the first complete model of the CUORE data, based on 1038 kg yr of collected exposure. Thanks to optimized data selection, we achieve a factor of two improvement in precision, obtaining T1/2 = (9.32 +0.05 -0.04 (stat.) +0.07 -0.07 (syst.)) x10^20 yr. The signal-to-background ratio is increased by 70% compared to our previous results, enabling the first application of the improved 2nbb formalism to 130Te. Within this framework, we determine a credibility interval for the effective axial coupling in the nuclear medium as a function of nuclear matrix elements. We also extract values for the higher-order nuclear matrix element ratios: second-to-first and third-to-first. The second-to-first ratio agrees with nuclear model predictions, while the third-to-first ratio deviates from theoretical expectations. These findings provide essential tests of nuclear models and key inputs for future 0nbb searches.

nucl-ex↗

arXiv2025

Ion Transport on Phased Radiofrequency Carpets in Xenon Gas

We present the design and performance of a four-phased radiofrequency (RF) carpet system for ion transport in high-pressure xenon gas. The RF carpet, designed with a 160 $\mu$m pitch, is applied to the lateral collection of ions in xenon at pressures up to 600 mbar. We demonstrate transport efficiency of caesium ions across varying pressures, and compare with microscopic simulations made in the SIMION package. The novel use of an N-phased RF carpet at high pressure can achieve ion levitation and controlled lateral motion in a denser environment than is typical for RF ion transport in gases. This feature makes such carpets strong candidates for ion transport to single ion sensors envisaged for future neutrinoless double-beta decay experiments in xenon gas.

physics.ins-det↗

arXiv2024

Search for fractionally charged particles with CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) is a detector array comprised by 988 5$\;$cm$\times$5$\;$cm$\times$5$\;$cm TeO$_2$ crystals held below 20 mK, primarily searching for neutrinoless double-beta decay in $^{130}$Te. Unprecedented in size amongst cryogenic calorimetric experiments, CUORE provides a promising setting for the study of exotic through-going particles. Using the first tonne-year of CUORE's exposure, we perform a search for hypothesized fractionally charged particles (FCPs), which are well-motivated by various Standard Model extensions and would have suppressed interactions with matter. No excess of FCP candidate tracks is observed over background, setting leading limits on the underground FCP flux with charges between $e/24-e/5$ at 90\% confidence level. Using the low background environment and segmented geometry of CUORE, we establish the sensitivity of tonne-scale sub-Kelvin detectors to diverse signatures of new physics.

hep-ex↗

arXiv2024

Data-driven background model for the CUORE experiment

We present the model we developed to reconstruct the CUORE radioactive background based on the analysis of an experimental exposure of 1038.4 kg yr. The data reconstruction relies on a simultaneous Bayesian fit applied to energy spectra over a broad energy range. The high granularity of the CUORE detector, together with the large exposure and extended stable operations, allow for an in-depth exploration of both spatial and time dependence of backgrounds. We achieve high sensitivity to both bulk and surface activities of the materials of the setup, detecting levels as low as 10 nBq kg$^{-1}$ and 0.1 nBq cm$^{-2}$, respectively. We compare the contamination levels we extract from the background model with prior radio-assay data, which informs future background risk mitigation strategies. The results of this background model play a crucial role in constructing the background budget for the CUPID experiment as it will exploit the same CUORE infrastructure.

nucl-ex↗

arXiv2024

Constraints on Lepton Number Violation with the 2 tonne$\cdot$yr CUORE Dataset

Matter-antimatter asymmetry underlines the incompleteness of the current understanding of particle physics. Neutrinoless double-beta decay ($0\nu \beta\beta$) may help explain this asymmetry, while unveiling the Majorana nature of the neutrino. The CUORE experiment searches for $0\nu \beta\beta$ of $^{130}$Te using a tonne-scale cryogenic calorimeter operated at milli-kelvin temperatures. We report no evidence of $0\nu \beta\beta$ and place a lower limit on the half-life of $T_{1/2} >3.5 \times$ 10$^{25}$~years (90\% C.I.) with over 2~tonne$\cdot$year TeO$_2$ exposure. The tools and techniques developed for this result and the 5 year stable operation of nearly 1000 detectors demonstrate crucial infrastructure for a future-generation experiment capable of searching for $0\nu \beta\beta$ across multiple isotopes.

nucl-ex↗

arXiv2023

NvDEx-100 Conceptual Design Report

Observing nuclear neutrinoless double beta (0vbb) decay would be a revolutionary result in particle physics. Observing such a decay would prove that the neutrinos are their own antiparticles, help to study the absolute mass of neutrinos, explore the origin of their mass, and may explain the matter-antimatter asymmetry in our universe by lepton number violation. We propose developing a time projection chamber (TPC) using high-pressure 82SeF6 gas and top-metal silicon sensors for read-out in the China Jinping Underground Laboratory (CJPL) to search for neutrinoless double beta decay of 82Se, called the NvDEx experiment. Besides being located at CJPL with the world's thickest rock shielding, NvDEx combines the advantages of the high Qbb (2.996 MeV) of 82Se and the TPC's ability to distinguish signal and background events using their different topological characteristics. This makes NvDEx unique, with great potential for low-background and high-sensitivity 0vbb searches. NvDEx-100, a NvDEx experiment phase with 100 kg of SeF6 gas, is being built, with plans to complete installation at CJPL by 2025. This report introduces 0vbb physics, the NvDEx concept and its advantages, and the schematic design of NvDEx-100, its subsystems, and background and sensitivity estimation.

physics.ins-det↗

arXiv2022

Solid State Detectors and Tracking for Snowmass

Tracking detectors are of vital importance for collider-based high energy physics (HEP) experiments. The primary purpose of tracking detectors is the precise reconstruction of charged particle trajectories and the reconstruction of secondary vertices. The performance requirements from the community posed by the future collider experiments require an evolution of tracking systems, necessitating the development of new techniques, materials and technologies in order to fully exploit their physics potential. In this article we summarize the discussions and conclusions of the 2022 Snowmass Instrumentation Frontier subgroup on Solid State and Tracking Detectors (Snowmass IF03).

physics.ins-det↗

arXiv2022

An Energy-dependent Electro-thermal Response Model of CUORE Cryogenic Calorimeter

The Cryogenic Underground Observatory for Rare Events (CUORE) is the most sensitive experiment searching for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{130}\text{Te}$. CUORE uses a cryogenic array of 988 TeO$_2$ calorimeters operated at $\sim$10 mK with a total mass of 741 kg. To further increase the sensitivity, the detector response must be well understood. Here, we present a non-linear thermal model for the CUORE experiment on a detector-by-detector basis. We have examined both equilibrium and dynamic electro-thermal models of detectors by numerically fitting non-linear differential equations to the detector data of a subset of CUORE channels which are well characterized and representative of all channels. We demonstrate that the hot-electron effect and electric-field dependence of resistance in NTD-Ge thermistors alone are inadequate to describe our detectors' energy dependent pulse shapes. We introduce an empirical second-order correction factor in the exponential temperature dependence of the thermistor, which produces excellent agreement with energy-dependent pulse shape data up to 6 MeV. We also present a noise analysis using the fitted thermal parameters and show that the intrinsic thermal noise is negligible compared to the observed noise for our detectors.

physics.ins-det↗

arXiv2022

New direct limit on neutrinoless double beta decay half-life of $^{128}$Te with CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) at Laboratori Nazionali del Gran Sasso of INFN in Italy is an experiment searching for neutrinoless double beta (0$\nu\beta\beta$) decay. Its main goal is to investigate this decay in $^{130}$Te, but its ton-scale mass and low background make CUORE sensitive to other rare processes as well. In this work, we present our first results on the search for \nbb decay of $^{128}$Te, the Te isotope with the second highest natural isotopic abundance. We find no evidence for this decay, and using a Bayesian analysis we set a lower limit on the $^{128}$Te \nbb decay half-life of T$_{1/2} > 3.6 \times 10^{24}$ yr (90\% CI). This represents the most stringent limit on the half-life of this isotope, improving by over a factor 30 the previous direct search results, and exceeding those from geochemical experiments for the first time.

nucl-ex↗

arXiv2022

Enhanced low-energy supernova burst detection in large liquid argon time projection chambers enabled by Q-Pix

The detection of neutrinos from core-collapse supernovae may reveal important process features as well as neutrino properties. The detection of supernova neutrinos is one of the main science drivers for future kiloton-scale neutrino detectors based on liquid argon. Here we show that for such detectors the intrinsically 3D readout in Q-Pix offers numerous advantages relative to a wire-based readout, such as higher reconstruction efficiency, lower energy threshold, considerably lower data rates, and potential pointing information.

hep-ex↗

arXiv2022

Snowmass 2021 White Paper: The Selena Neutrino Experiment

Imaging devices made from an ionization target layer of amorphous selenium (aSe) coupled to a silicon complementary metal-oxide-semiconductor (CMOS) active pixel array for charge readout are a promising technology for neutrino physics. The high spatial resolution in a solid-state target provides unparalleled rejection of backgrounds from natural radioactivity in the search for neutrinoless $\beta\beta$ decay and for electron neutrino ($\nu_e$) spectroscopy with $^{82}$Se. In this white paper, we summarize the broad scientific program of a large imaging detector with a 10-ton target of $^{82}$Se. We review the detector technology, and outline the ongoing research program to realize this experiment.

physics.ins-det↗