Characterization of the response of an Argon-based Dark Matter detector with the ReD experiment

by Luciano Pandola (Laboratori Nazionali del Sud INFN), Luciano Pandola (Istituto Nazionale di Fisica Nucleare)

Thursday 26 Oct 2023, 17:00 → 18:00 Europe/Rome

Aula B

The Recoil Directionality project (ReD) within the Global Argon Dark Matter Collaboration aims to characterize the light and charge response of a small liquid argon (LAr) dual-phase Time Projection Chamber (TPC) to neutron-induced nuclear recoils. The main goals of the project are to probe for the possible directional dependence suggested by the previous SCENE experiment and to study the response to very low-energy nuclear recoils. Sensitivity to directionality and to low-energy recoils are both key assets for future argon-based experiments looking for Dark Matter in the form of WIMPs, as the forthcoming DarkSide-20k.

The first measurement of ReD consisted in the irradiation of the LAr TPC with a neutron beam at the INFN, Laboratori Nazionali del Sud (LNS), Catania. The correlation of the ionisation and scintillation signals, which is a possible handle to measure the recoil direction of nuclei, was studied in detail for 70 keV nuclear recoils, using a neutron beam produced via the reaction p(7Li,7Be)n from a primary 7Li beam delivered by the TANDEM accelerator of LNS. A model based on directional modulation in charge recombination was used to describe the correlation, resulting in no indication of significant dependence of the detector response to the recoil direction.

A dedicated measurement to characterize the response of the TPC to very low-energy nuclear recoils (< 10 keV) was then carried out in Winter 2023 at INFN Sezione di Catania. The charge yield is a critical parameter for the experiments searching for Dark Matter in the form of low-mass WIMPs and measurements in Ar below 10 keV are scarce in the literature. The ReD measurement covers the gap down to 2 keV. The TPC was irradiated by neutrons produced by an intense 252Cf fission source in order to produce Ar recoils in the energy range of interest.

In this seminar, the experimental setups used for the two ReD campaign, the preliminary results from data analysis and the future perspectives will be presented and discussed.