The direct detection of dark matter is a key problem in astroparticle physics that generally involves the use of deep-underground laboratories for a low-background environment where the miniscule signals from dark matter interactions can be observed. A dark matter signal in an Earth-based detector is expected to modulate yearly due to the change of the Earth’s speed relative to the galactic halo reference frame. There is a long-standing result from the DAMA/LIBRA experiment at the Gran Sasso National Laboratory (LNGS) that used NaI(Tl) scintillator for the detector medium and is consistent with this scenario. However, the magnitude of the signal is in tension with a number of other direct detection measurements that use different detector technologies.
SABRE (Sodium-iodide with Active Background REjection) is a new NaI(Tl) experiment designed to search for galactic dark matter through the annual modulation signature. Arrays of NaI(Tl) detectors with unprecedented radio-purity will be operated inside volumes of active liquid scintillator to veto against both external and internal backgrounds, especially the 3 keV signature from the decay of 40K within the crystals. SABRE will be a dual-site experiment located at both LNGS (Italy) and in the Stawell Underground Physics Laboratory (SUPL) under development in Victoria (Australia). The operation of twin full-scale experiments in both the northern and southern hemispheres is an important factor that will strengthen the reliability of a dark matter detection result by discriminating against possible seasonal systematic effects.
This seminar will describe the international field of direct dark matter detection, the current status and plans for the SABRE experiment, with a focus on the activities where ANU is playing a major role, as well as the future research possibilities for the new underground laboratory in Stawell. The speaker is the technical coordinator for SABRE South.