Direct detection of MeV-scale dark matter utilizing germanium internal amplification for the charge created by the ionization of impurities

作者：Mei, D. -M.^*; Wang, G. -J.; Mei, H.; Yang, G.; Liu, J.; Wagner, M.; Panth, R.; Kooi, K.; Yang, Y. -Y.; Wei, W. -Z.

来源：European Physical Journal C, 2018, 78(3): 187.

DOI：10.1140/epjc/s10052-018-5653-z

• ATOMIC SCREENING CONSTANTS
• IMPACT IONIZATION
• ISOTOPE SCATTERING
• GE
• SEARCH

Light, MeV-scale darkmatter (DM) is an exciting DM candidate that is undetectable by current experiments. A germanium (Ge) detector utilizing internal charge amplification for the charge carriers created by the ionization of impurities is a promising new technology with experimental sensitivity for detecting MeV-scale DM. We analyze the physics mechanisms of the signal formation, charge creation, charge internal amplification, and the projected sensitivity for directly detecting MeV-scale DM particles. We present a design for a novel Ge detector at helium temperature (similar to 4K) enabling ionization of impurities from DM impacts. With large localized E-fields, the ionized excitations can be accelerated to kinetic energies larger than the Ge bandgap at which point they can create additional electron-hole pairs, producing intrinsic amplification to achieve an ultra-low energy threshold of similar to 0.1 eV for detecting low-mass DM particles in the MeV scale. Correspondingly, such a Ge detector with 1 kg-year exposure will have high sensitivity to a DM-nucleon cross section of similar to 5 x 10(-45) cm(2) at a DM mass of similar to 10 MeV/c(2) and a DM-electron cross section of similar to 5 x 10(-46) cm(2) at a DM mass of similar to 1 MeV/c(2).

• 出版日期2018-3-6
• 单位长江大学