Measurement of the 39Ar specific activity in atmospheric argon with DArT at the Canfranc Underground Laboratory
Abstract
We report the measurement of the 39Ar specific activity of atmospheric argon using DArT, a low-background single-phase liquid-argon detector read out by cryogenic silicon photomultipliers, at the Canfranc Underground Laboratory (LSC) in Spain. DArT was first filled with atmospheric argon and then with a sample of underground argon of known radioactivity from the DarkSide-50 experiment. The underground argon serves as a background reference in this measurement, making the result robust because we do not rely on background simulations. We measure the 39Ar specific activity with both a cut-and-count method and a binned maximum-likelihood fit, yielding consistent results. We obtain aAAr= 0.955 ± 0.008 Bq/kg. This result agrees with previous measurements from other experiments and provides the most precise determination of the 39Ar specific activity in atmospheric argon to date. It also validates DArT as a key component of the DArTInArDM experiment at LSC, which aims to measure the 39Ar activity of the argon extracted from deep underground wells in Colorado (USA) for the Darkside-20k and LEGEND-1000 experiments at Laboratori Nazionali del Gran Sasso in Italy.
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BibTeX
@misc{agnes2026measurement,
title = {{Measurement of the $^39$Ar specific activity in atmospheric argon with DArT at the Canfranc Underground Laboratory}},
author = {P Agnes and H.O Back and S Bharat and W.M Bonivento and M Boulay and M Caboni and N Canci and N Cargioli and P Castello and S Cebrián and L Consiglio and R Crampton and D. Diaz Mairena and D Franco and I Fuente-Ortega and F Gabriele and D Gahan and C Galbiati and P. Garcia Abia and T Hessel and S Horikawa and A Ianni and G Korga and M Kuźniak and L Luzzi and A Marasciulli and M Martínez and P Organtini and A. Ortiz de Solórzano and R Pavarani and P Pegoraro and V. Pesudo Fortes and M Razeti and O.U Rehman and L Romero and D Sablone and E Sánchez García and R Santorelli and C Seoane and J Sosiak and S Sulis and C Tierney and S Tullio and G Vera Díaz},
howpublished = {HAL},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.39400},
eprint = {2609.39400},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05781919v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Measurement of the ^39Ar specific activity in atmospheric argon with DArT at the Canfranc Underground Laboratory
AU - P Agnes
AU - H.O Back
AU - S Bharat
AU - W.M Bonivento
AU - M Boulay
AU - M Caboni
AU - N Canci
AU - N Cargioli
AU - P Castello
AU - S Cebrián
AU - L Consiglio
AU - R Crampton
AU - D. Diaz Mairena
AU - D Franco
AU - I Fuente-Ortega
AU - F Gabriele
AU - D Gahan
AU - C Galbiati
AU - P. Garcia Abia
AU - T Hessel
AU - S Horikawa
AU - A Ianni
AU - G Korga
AU - M Kuźniak
AU - L Luzzi
AU - A Marasciulli
AU - M Martínez
AU - P Organtini
AU - A. Ortiz de Solórzano
AU - R Pavarani
AU - P Pegoraro
AU - V. Pesudo Fortes
AU - M Razeti
AU - O.U Rehman
AU - L Romero
AU - D Sablone
AU - E Sánchez García
AU - R Santorelli
AU - C Seoane
AU - J Sosiak
AU - S Sulis
AU - C Tierney
AU - S Tullio
AU - G Vera Díaz
PY - 2026
DA - 2026/10/01
PB - HAL
DO - 10.48550/arxiv.2609.39400
UR - https://hal.science/hal-05781919v1
AB - We report the measurement of the ^39Ar specific activity of atmospheric argon using DArT, a low-background single-phase liquid-argon detector read out by cryogenic silicon photomultipliers, at the Canfranc Underground Laboratory (LSC) in Spain. DArT was first filled with atmospheric argon and then with a sample of underground argon of known radioactivity from the DarkSide-50 experiment. The underground argon serves as a background reference in this measurement, making the result robust because we do not rely on background simulations. We measure the ^39Ar specific activity with both a cut-and-count method and a binned maximum-likelihood fit, yielding consistent results. We obtain a_AAr= 0.955 ± 0.008 Bq/kg. This result agrees with previous measurements from other experiments and provides the most precise determination of the ^39Ar specific activity in atmospheric argon to date. It also validates DArT as a key component of the DArTInArDM experiment at LSC, which aims to measure the ^39Ar activity of the argon extracted from deep underground wells in Colorado (USA) for the Darkside-20k and LEGEND-1000 experiments at Laboratori Nazionali del Gran Sasso in Italy.
ER -