Ultra-low energy nuclear recoil calibration in liquid xenon using the MiX detector*

The Michigan Xenon (MiX) system is a small dual-phase time projection chamber at the University of Michigan. It is being adapted to perform measurements of the photon and electron yields of liquid xenon (LXe) in response to low energy nuclear recoils, which will allow LXe experiments to be more sensitive to light dark matter. We plan on bombarding Xe with slow (<~ 1 eV) neutrons. Nuclei that capture these neutrons de-excite with gamma cascades and any asymmetry in a cascade will result in the nucleus recoiling, with a maximum energy of 0.3 keV. Simulations indicate that with a pulsed neutron source and a water tank to moderate the neutrons, the captures can feasibly be isolated in time. In this talk we will present the status of the MiX detector, including hardware upgrades and early performance studies.