Ponente
Descripción
Dark matter (DM), which constitutes five-sixths of all matter, is hypothesized to be a weakly interacting non-baryonic particle, created in the early stages of cosmic evolution. There are several experiments that aim for the detection of DM. One of the most promising candidates of DM is the Weakly Interacting Massive Particles or WIMPs. The DarkSide project aims at the direct detection of DM. It is a dual-phase liquid argon time projection chamber (LAr TPC), in which the DM is expected to interact with the argon nucleus resulting in nuclear recoils. Scintillation signal (S1) is produced as a result of the ionizing events from the DM-Ar interaction. Impurities such as O2, N2, H2O, etc. in LAr at the ppm level reduces the scintillation. These scintillation photons (128 nm) are emitted from two excimer states: the long-lived triplet state (1.5 us) and short-lived singlet state (6 ns). The N2 contamination in LAr suppresses the triplet component. Our aim is to get high-purity underground argon for the current and future DM searches. We analyse data from the DarkSide-50 experiment to obtain a lifetime of the triplet component with known purity, and then use the value as a reference for purity level in the DArT experiment, which is specifically designed for the impurity check of underground argon.
