arXiv subjects

Nicolas Abgrall

Publications and source records attributed to Nicolas Abgrall.

6 recordsLinked to original sources

arXiv2026

Automatic calibration of gamma-ray detectors deployed in uncontrolled environments

Radiation detectors deployed as part of a large urban network or for homeland security monitoring must maintain reliable energy calibration even when subjected to substantial variations in temperature and ambient background radiation. Traditional calibration methods often rely on power-intensive temperature stabilization or peak-locking algorithms that are susceptible to environmental changes. This publication presents a novel software-based calibration method that eliminates the need for active temperature control by utilizing full-spectrum analysis. The method continuously updates the calibration parameters by fitting the spectral data with a series of background radiation contributions (K, U, Th series, radon progeny and cosmics) combined with a Monte-Carlo-based physical detector model that incorporates light yield non-proportionality and photomultiplier tube saturation. Performance was validated using simulated data, measurements in an environmental chamber across a wide temperature range (-25C to +50C), and data from a multi-day outdoor field deployment. Results demonstrate that the method successfully maintains stable energy calibration despite significant ambient temperature variations and precipitation events. The technique effectively decouples instrumental drift from spectral changes caused by environmental background fluctuations. This approach provides a robust, automated, and low-power alternative to conventional calibration techniques, enabling the practical deployment of large-scale, unattended networked detector systems.

physics.ins-det↗

arXiv2025

Curation and Dissemination of Complex Multi-modal Data Sets for Radiation Detection, Localization, and Tracking

The PANDAWN sensor network in Chicago, IL, is a state-of-the-art test-bed for networked, multi-modal sensing. It integrates AI/data science methods into its operation, from data acquisition to automated data labeling and curation workflows. The curation and dissemination of diverse multi-modal data sets will enable the development of new radiological/nuclear (R/N) detection, localization, and tracking algorithms, and methods relevant across the nonproliferation mission space. This paper first introduces the PANDAWN sensor network and the features that make it stand out from previous multi-modal data acquisition efforts. We then review the various data streams acquired on the PANDAWN nodes, and present the implementation of an automated data curation pipeline that includes the labeling of radiation and contextual data streams. We finally provide a short overview of different studies that leveraged the curated data sets.

physics.app-ph↗

arXiv2025

Characterization of precipitation-induced radon progeny deposition events using a city-scale sensor network

Networks of radiation detectors provide a platform for real-time radioactive source detection and identification in urban environments. Detection algorithms in these systems must adapt to naturally-occurring changes in background, which requires well-characterized relationships between precipitation events and their corresponding radiological signature. We present a description of rain-induced radon progeny deposition events occurring in Chicago from September 2023 through February 2024. We measure ambient gamma radiation levels, precipitation rate, temperature, pressure and relative humidity in a network of sensor nodes. For each identified precipitation period, we decompose spectra into static- and radon-associated components as defined by a non-negative matrix factorization (NMF) algorithm. We find a consistent power-law relationship between a precipitation-dependent peak of the radon progeny proxy (RPP) and the peak strength of radon-associated NMF component for most precipitation events. We conduct a case study of a rainfall period with abnormally high levels of implied radon progeny concentration and describe its temporal and spatial evolution. We hypothesize this phenomenon is due to the air mass path that intersects a uranium-rich region of Wyoming. Finally, we cluster precipitation events into three distinct categories. One category roughly corresponds to events with deep low-pressure systems and high relative radon concentration, while another is characteristic of light stratiform rain with slightly higher temperatures and intermediate relative radon concentration. The third category contains a weak-gradient or lake breeze convection showers with intermittent precipitation and low relative radon concentration. These findings suggest that radiological anomaly detection could be improved by training unique background models corresponding to each category of meteorological event.

physics.geo-ph↗

arXiv2015

Status Update of the MAJORANA DEMONSTRATOR Neutrinoless Double Beta Decay Experiment

Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The \textsc{Majorana} Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in $^{76}$Ge. The \textsc{Majorana Demonstrator}, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in $^{76}$Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched detectors.

physics.ins-det↗

arXiv2011

The NA61/SHINE long target pilot analysis for T2K

The NA61/SHINE collaboration performed measurements of pC interactions at 31 GeV/c beam momentum with a full size replica of the T2K target (1.9 interaction length) during a pilot run in 2007. Larger statistics runs were also conducted in 2009 and 2010. The NA61/SHINE setup consists in a large acceptance spectrometer located on the H2 beamline of the SPS at CERN. For the first time, the kinematical phase space of interest for an accelerator based neutrino experiment (i.e. kinematical phase space of pions/kaons exiting the target and producing neutrinos in the direction of the near and far detectors) is fully covered by a single hadron production experiment. In a first stage, yields of positively charged pions were measured at the surface of the target. The analysis of the 2007 data set presented here demonstrates that a) high quality long target data were successfully taken with the NA61/SHINE apparatus, and b) for the first time, the T2K neutrino flux predictions can effectively be re-weighted with the NA61/SHINE long target data.

hep-ex↗

arXiv2010

NA61-SHINE: Hadron Production Measurements for Cosmic Ray and Neutrino Experiments

As neutrino long baseline experiments enter a new domain of precision, important systematic errors due to poor knowledge of production cross-sections for pions and kaons require more dedicated measurements for precise neutrino flux predictions. The cosmic ray experiments require dedicated hadron production measurements to tune simulation models used to describe air shower profiles. Among other goals, the NA61-SHINE (SPS Heavy Ion and Neutrino Experiment) experiment at the CERN SPS aims at precision measurements (5% and below) for both neutrino and cosmic ray experiments: those will improve the prediction of the neutrino flux for the T2K experiment at J-PARC and the prediction of muon production in the propagation of air showers for the Auger and KASCADE experiments. Motivations for new hadron production measurements are briefly discussed. NA61-SHINE took data during a pilot run in 2007 and in 2009 with different Carbon targets. The NA61-SHINE setup and preliminary spectra for positive and negative pions obtained with the 2007 thin (4% interaction length) Carbon target data are presented. The use of the NA61 data for the T2K neutrino flux predictions is finally discussed in further details.

hep-ex↗