Feasibility study to use neutron capture for an ultralow energy nuclear-recoil calibration in liquid xenon

The feasibility of an ultralow energy nuclear-recoil measurement in liquid xenon using neutron capture is investigated for a small (subkilogram) liquid xenon detector that is optimized for a high scintillation gain, and a pulsed neutron source. The measurement uses the recoil energies imparted to xenon nuclei during the deexcitation process following neutron capture, where promptly emitted gamma cascades can provide the nuclei with up to 0.3 keV(nr) of recoil energy due to conservation of momentum. A successful calibration of scintillation photon and ionization electron yields below this energy will contribute to a greater sensitivity for liquid xenon experiments in searches for light weakly interacting massive particles.