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

作者：Pyle M^*; Bauer D A; Cabrera B; Hall J; Schnee R W; Thakur R Basu; Yellin S

来源：Journal of Low Temperature Physics, 2012, 167(5-6): 1081-1086.

DOI：10.1007/s10909-012-0583-x

• Dark matter
• Low mass WIMP

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|=40 V/cm without producing leakage in CDMS II Ge detectors, allowing sensitivity to a benchmark WIMP with mass M (chi) =8 GeV/c(2) and sigma=1.8x10(-42) cm(2) (with significant sensitivity for M (chi) %26gt; 2 GeV/c(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 %26lt; 10(-8) for a simulated 20 kg-day experiment with a benchmark WIMP signal with M (chi) =8 GeV/c(2) and sigma=3.3x10(-41) cm(2).

• 出版日期2012-6