%0 Journal Article %T Low-Mass WIMP Sensitivity and Statistical Discrimination of Electron and Nuclear Recoils by Varying Luke-Neganov Phonon Gain in Semiconductor Detectors %A M. Pyle %A D. A. Bauer %A B. Cabrera %A J. Hall %A R. W. Schnee %A R. Basu Thakur %A S. Yellin %J Physics %D 2012 %I arXiv %R 10.1007/s10909-012-0583-x %X 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. %U http://arxiv.org/abs/1201.3685v1