The MIGDAL experiment: Measuring a rare atomic process to aid the search for dark matter

• Lex Millins (University of Birmingham (GB))

Dark matter makes up most of the mass content in the universe, yet its nature remains one of the biggest unanswered questions in physics. Many experiments are searching for WIMP-like dark matter directly and exploiting improvements in sensitivity thanks to the Migdal effect, a rare atomic process. However, this process is yet to be observed in nuclear scattering. The MIGDAL experiment aims to make the first unambiguous observation of the Migdal effect in nuclear scattering. A low pressure Optical Time Projection Chamber (OTPC) is used to perform 3D imaging of the characteristic Migdal signal - an electron and a nuclear recoil sharing a common vertex. Nuclear recoils are induced using fast neutrons from a D-D generator which scatter in the gaseous volume. Both ionisation charge and scintillation light are read-out and these measurements are combined for complete three-dimensional track reconstruction. In this seminar I will discuss the detector performance and results of commissioning with fast neutrons at the Neutron Irradiation Laboratory for Electronics (NILE) at Rutherford Appleton Laboratory in the UK, along with the first science operations of the experiment.