Radon studies at CPPM Radon Platform for Direct Dark Matter and zero background experiment

Radon is a radioactive noble gas produced in the series of uranium and thorium decay. In particular, the 222Rn isotope, whose decay period is 3.8 days, is one of the largest sources of naturally occurring radiation exposure. In particle and astroparticle physics of very rare and low-energy events like neutrinoless double beta decay and Direct Dark Matter research, the decay of 222Rn (Rn) and its daughters, is often the main sensibility limitation for many experiments. In this context future-generation experiments will require radon concentrations at the level of only a few atoms per cubic meter or per kilogram and achieving such extremely low concentrations demands the use of highly efficient radon adsorbents.

The CPPM radon platform is a dedicated platform for the general study of radon physics: Emanation, transport, adsorption and detection. In this context, the IRENE project, launched in February 2024, brings together CPPM and four laboratories specializing in physical chemistry and materials science. Its objective is to understand, optimize, and develop innovative materials for extreme radon adsorption, with a particular focus on xenon-based applications. We are also working on the development of new methods to study the emanation, transport and adsorption of radon depending of the temperature, pressure and the environment in order to better evaluate its release or capture under the operating conditions of low-background experiments which often operate in two-phase cryogenic environments, notably LAr/GAr or LXe/GXe.

In this presentation, i will start by talking about the radon-induced background in Direct Dark Matter and zero background experiment. Then i will introduce the Radon fields of studies and will continue by describing the CPPM radon platform, its activities, and results. Finally, i will discuss the new methods we are developing and some preliminary results.