Low-Mass WIMP Sensitivity and Statistical Discrimination of Electron and Nuclear Recoils by Varying Luke-Neganov Phonon Gain in Semiconductor Detectors

Abstract

Amplifying the phonon signal in a semiconductor dark matter detector can be accomplished by operating at high voltage bias and converting the electrostatic potential energy into Luke-Neganov phonons. This amplification method has been validated at up to |E|=40V/cm without producing leakage in CDMSII Ge detectors, allowing sensitivity to a benchmark WIMP with mass = 8GeV and cross section 1.8e-42cm^2 assuming flat electronic recoil backgrounds near threshold. Furthermore, for the first time we show that differences in Luke-Neganov gain for nuclear and electronic recoils can be used to discriminate statistically between low-energy background and a hypothetical WIMP signal by operating at two distinct voltage biases. Specifically, 99% of events have p-value<1e-8 for a simulated 20kg-day experiment with a benchmark WIMP signal with mass =8GeV and cross section =3.3e-41cm^2.

6 pages, 5 figures To be published in Journal of Low Temperature Physics

References in corpus (5)

• First results from DAMA/LIBRA and the combined results with DAMA/NaI
• Results from a Search for Light-Mass Dark Matter with a P-type Point Contact Germanium Detector
• A search for light dark matter in XENON10 data
• Results from a Low-Energy Analysis of the CDMS II Germanium Data
• Phonon Pulse Shape Discrimination in SuperCDMS Soudan

Cited by in corpus (5)

• Projected Sensitivity of the SuperCDMS SNOLAB experiment
• Semiconductor Probes of Light Dark Matter
• Magnetic Bubble Chambers and Sub-GeV Dark Matter Direct Detection
• Dark Matter Direct Search Rates in Simulations of the Milky Way and Sagittarius Stream
• Atomic limits in the search for galactic dark matter