Separating $${^{39}\hbox {Ar}}$$ from $${^{40}\hbox {Ar}}$$ by cryogenic distillation with Aria for dark-matter searches

Abstract

Aria is a plant hosting a $${350}\,\hbox {m}$$ 350 m cryogenic isotopic distillation column, the tallest ever built, which is being installed in a mine shaft at Carbosulcis S.p.A., Nuraxi-Figus (SU), Italy. Aria is one of the pillars of the argon dark-matter search experimental program, lead by the Global Argon Dark Matter Collaboration. It was designed to reduce the isotopic abundance of $${^{39}\hbox {Ar}}$$ 39 Ar in argon extracted from underground sources, called Underground Argon (UAr), which is used for dark-matter searches. Indeed, $${^{39}\hbox {Ar}}$$ 39 Ar is a $$\beta $$ β -emitter of cosmogenic origin, whose activity poses background and pile-up concerns in the detectors. In this paper, we discuss the requirements, design, construction, tests, and projected performance of the plant for the isotopic cryogenic distillation of argon. We also present the successful results of the isotopic cryogenic distillation of nitrogen with a prototype plant.

The Selena Neutrino Experiment

“…We will explore this possibility as part of the Selena program. We note the synergies with other efforts in our community, e.g., the Aria project, which aims to remove 39 Ar from natural argon by distillation [30].…”

Impact of the Dresden-II and COHERENT neutrino scattering data on neutrino electromagnetic properties and electroweak physics

“…In this analysis, we set (Z, N ) Cs = (55, 78), (Z, N ) I = (53,74) and (Z, N ) Ar = (18,22). Actually, one should consider that atmospheric argon is contaminated by a small percentage of 36 Ar and 38 Ar, namely f( 36 Ar) = 0.33% and f( 38 Ar) = 0.06% [40]. However, since the amount of these contaminants is very small and the uncertainties are large, in practice one gets the same results considering f( 40 Ar) = 100%.…”

“…However, since the amount of these contaminants is very small and the uncertainties are large, in practice one gets the same results considering f( 40 Ar) = 100%. For Ge we use (Z, N )70,72,73,74,76 Ge = (32, (38,40,41,42,44)) with the corresponding natural abundances of 0.2057, 0.2745, 0.0775, 0.3650, 0.0773 [41]. The neutrino-proton, g p V , and neutrino-neutron, g n V , vector couplings correspond to g p V (ν e ) = 0.0382, g p V (ν µ ) = 0.0300 and g n V = −0.5117, when taking into account radiative corrections in the MS scheme [14,42,43].…”

“…The proton rms radii can be obtained from the muonic atom spectroscopy and electron scattering data [47][48][49] as explained in ref. [14], and correspond to On the other hand, there is poor knowledge of the values of the 133 Cs, 127 I, 40 Ar, and Ge neutron rms radii using electroweak probes [14, 19-21, 23-25, 50, 51]. The values of these neutron rms radii can, however, be estimated with theoretical calculations based on different nuclear models [14,17,52].…”

Snowmass2021 Cosmic Frontier White Paper: Calibrations and backgrounds for dark matter direct detection

“…While 39 Ar production mechanisms also exist underground [249], one source of UAr was demonstrated to have an activity of 7.3 × 10 −4 Bq/kg [242]. New facilities are under development to extract and purify several tonnes of UAr from this source [250]. Cosmogenic activation during transportation and storage is also a concern [245], and new methods to screen UAr are under development [251].…”