While most experimental searches for WIMP dark matter have come up empty, there is one experiment, known as DAMA, that has claimed to have detected dark matter, and no one has yet been able to confirm or refute the claim. Determining the nature of the DAMA anomaly is the main motivation for the first experiment which is the first major experiment to be housed at the underground laboratory, SUPL.
The SABRE South vessel
When it commences data-taking 2022, SABRE (Sodium Iodide with Active Background Rejection Experiment) South will consist of seven crystals made of sodium iodide. These crystals are ultra-pure. In fact, we have recently performed measurements of the radioactive backgrounds in our first such crystal, demonstrating that it is the purest crystal of its kind to ever have been made. This purity is essential for reducing the rate of backgrounds from trace radioactivity in the detector, which otherwise limits its sensitivity to WIMPs. Although the backgrounds from the crystals are small, SABRE South will further suppress them by submerging the crystals enclosures in a large, 10 tonne liquid scintillator veto detector. The usefulness of this veto detector stems can be seen when one considers that many radioactive decays emit two types of particle: electrons (which tend to be localised in the crystals), and gamma rays (which tend to escape). The veto detector will catch most of these gamma rays, allowing us to identify detection events as background which might otherwise be mistaken for a WIMP signal. The SABRE crystals and veto will also be shielded from external radiation produced by the nearby rocks using Australian-produced steel, and plastic. More information on the SABRE experiment is available at https://www.sabre-experiment.org.au/.
