Development of LEAR: A Dual-Phase Argon Time Projection Chamber for the Study of Low Energy Argon Recoils

Abstract

DarkSide-LowMass (DS-LM) is a conceptual design of a dual-phase argon time projection chamber (TPC), optimized for sensitivity to light dark matter (below 10 GeV/(c^2)). Improvements to dark matter search sensitivity will require a detailed understanding of the minimum detectable recoil energy and background rate. This thesis details a contribution to LEAR (Low Energy Argon Recoils), a small R&D dual-phase argon TPC, to be used to study the effects of spiked impurity concentrations on the spurious electron background observed in DarkSide-50, measure the nuclear recoil ionization yield down to (\sim 1\ \text{keV}_{nr}), and observe the Migdal effect for the first time in liquid argon. We describe the development of the diving bell, bubbler, and liquid-level meter system, detector simulation, performance of event reconstruction software, and expected experimental signatures of the Migdal effect in our TPC.