Lowering the low-energy threshold of xenon detectors

Understand

We show that the energy threshold for nuclear recoils in the XENON10 dark matter search data can be lowered to ~1 keV, by using only the ionization signal.

• In other words, we make no requirement that a valid event contain a primary scintillation signal.
• We therefore relinquish incident particle type discrimination, which is based on the ratio of ionization to scintillation in liquid xenon.
• This method compromises the detector's ability to precisely determine the z coordinate of a particle interaction.