Ponente
Descripción
The use of large amounts of low-radioactivity Argon is envisaged in the context of different projects related to rare event searches like the direct detection of dark matter or neutrino studies.
Material activation due to exposure to cosmic rays may become an important background source for experiments investigating these phenomena.
In the case of DarkSide-20k, the extraction and purification of 120 tons of underground Ar (UAr) depleted in 39Ar is foreseen. Cosmogenic yields of relevant induced long-lived radioisotopes have been estimated to set the requirements and procedures during the preparation of the experiment; production rates, either measured or calculated, have been considered. The activity of 39Ar induced during extraction, purification and transport on surface is evaluated to be 2.8% of the activity measured in UAr by DarkSide-50 experiment, which used the same underground source, and thus considered acceptable. Other isotopes in the UAr such as 37Ar and 3H are shown not to be relevant due to short half-life and the assumed purification methods. The results of this study can be useful to set limits on exposure for the procurement of radiopure UAr in future LAr projects.
