First Measurement of Discrimination between Helium and Electron Recoils in Liquid Xenon for Low-Mass Dark Matter Searches
S. J. Haselschwardt (Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA); R. Gibbons (Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA, University of California, Berkeley, Department of Physics, Berkeley, California 94720-7300, USA); H. Chen (Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA); S. Kravitz (Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA); A. Manalaysay (Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA); et al - Show all 8 authors
We report the first measurement of discrimination between low-energy helium recoils and electron recoils in liquid xenon. This result is relevant to proposed low-mass dark matter searches which seek to dissolve light target nuclei in the active volume of liquid-xenon time projection chambers. Low-energy helium recoils were produced by degrading particles from with a gold foil situated on the cathode of a liquid xenon time-projection chamber. The resulting population of helium recoil events is well separated from electron recoils and is also offset from the expected position of xenon nuclear recoil events.
