1201.3685 (M. Pyle et al.)

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

M. Pyle, D. A. Bauer, B. Cabrera, J. Hall, R. W. Schnee, R. Basu Thakur, S. Yellin

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.

View original: http://arxiv.org/abs/1201.3685