Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches

TL;DR

This paper reports the first measurement of argon isotopic separation using the Aria cryogenic distillation prototype, demonstrating the separation of argon isotopes crucial for dark matter detection experiments.

Contribution

It presents the first experimental results of argon isotopic separation with the Aria plant prototype, including operating parameters and comparison with simulation software.

Findings

Successful separation of Ar36, Ar38, and Ar40 isotopes

Agreement between experimental results and process simulations

Advancement in argon purification for dark matter searches

Abstract

The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: Ar$^{36}$, Ar$^{38}$, and Ar$^{40}$. We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019.