An Improved Nuclear Recoil Calibration in the LUX Detector Using a Pulsed D-D Neutron Generator

The LUX dark matter experiment has measured the nuclear recoil charge (Qy) and light (Ly) yields in liquid xenon (LXe) down to 0.7 keVnr and 1.1 keVnr, respectively, in situ using a D-D neutron calibration source. Improvements in the D-D calibration have been possible by incorporating pulsing technique with narrow pulses (20 us / 250 Hz). This technique allows the suppression of accidental backgrounds in D-D neutron data and also provides increased sensitivity for the lower energy NR calibrations. I will report the improved NR absolute Qy and Ly measurements using the pulsed D-D calibration technique performed in situ in the LUX detector. This in situ energy calibration, using pulsed D-D neutron, represents the lowest energy NR that has been explored in liquid Xe and are accompanied by a significant improvement in calibration uncertainty.