The Large Underground Xenon (LUX) experiment is a dual-phase liquid xenon
time projection chamber (TPC) operating at the Sanford Underground Research
Facility in Lead, South Dakota. A calibration of nuclear recoils in liquid
xenon was performed $\textit{in situ}$ in the LUX detector using a collimated
beam of mono-energetic 2.45 MeV neutrons produced by a deuterium-deuterium
(D-D) fusion source. The nuclear recoil energy from the first neutron scatter
in the TPC was reconstructed using the measured scattering angle defined by
double-scatter neutron events within the active xenon volume. We measured the
absolute charge ($Q_{y}$) and light ($L_{y}$) yields at an average electric
field of 180 V/cm for nuclear recoil energies spanning 0.7 to 74 keV and 1.1 to
74 keV, respectively. This calibration of the nuclear recoil signal yields will
permit the further refinement of liquid xenon nuclear recoil signal models and,
importantly for dark matter searches, clearly demonstrates measured ionization
and scintillation signals in this medium at recoil energies down to
$\mathcal{O}$(1 keV).