Identification of Radon Decays in the LZ Dark Matter Search

Author: Daniel Tronstad, Department of Physics

Mentor: Dr. Richard Schnee, Department of Physics

Dark matter, which does not interact with light, is thought to make up approximately 85% of the matter in the universe, with the remaining 15% being normal matter. The LZ experiment, currently under construction 4850 ft underground at the Sanford Underground Research Facility, is designed to directly detect dark matter. Because dark matter interactions are very rare, LZ will need to minimize the number of other interactions that appear to be dark matter interactions.

The dominant source of these “fake” dark matter interactions is from radioactive decays of 214Pb, the grand-daughter of the noble gas, radon. However, it may be possible to identify 214Pb decays by their positions and times relative to easily identified alpha decays in the radon decay chain. My work combines modeling the motion of atoms in the LZ liquid flow and electric field with simulations of radioactive decays in the LZ detector to simulate the data we would expect to collect from the decay of radon in LZ. The simulated data can then be used to develop analysis tools to identify 214Pb decays and eliminate them as possible dark matter interactions.