Direct Detection of MeV-Scale Dark Matter Utilizing Germanium Internal Amplification for the Charge Created by the Ionization of Impurities

Abstract

Light, MeV-scale dark matter (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 ($\sim$4 K) 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 $\sim$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 $\sim$5$\times$10${}^{-45}$ cm${}^2$ at a DM mass of $\sim$10 MeV/c${}^2$ and a DM-electron cross section of $\sim$5$\times$10${}^{-46}$cm${}^2$ at a DM mass of $\sim$1 MeV/c${}^2$.

arXiv comment12 pages, 15 figures

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Cited by in corpus (14)

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• MeV Dark Matter Complementarity and the Dark Photon Portal
• Mapping The Neutrino Floor For Dark Matter-Electron Direct Detection Experiments
• Fabrication and Characterization of High-Purity Germanium Detectors with Amorphous Germanium Contacts
• Impact of Charge Trapping on the Energy Resolution of Ge Detectors for Rare-Event Physics Searches
• Characterization of High-Purity Germanium (Ge) Crystals for Developing Novel Ge Detectors
• The Impact of the Charge Barrier Height on Germanium (Ge) Detectors with Amorphous-Ge Contacts for Light Dark Matter Searches
• Scalar Co-SIMP Dark Matter: Models and Sensitivities
• Evidence of cluster dipole states in germanium detectors operating at temperatures below 10 K
• Development of Planar P-type Point Contact Germanium Detectors for Low-Mass Dark Matter Searches
• Development of low-threshold detectors for low-mass dark matter searches with a p-type germanium detector operated at cryogenic temperature
• Interpretation of XENON1T excess with MeV boosted dark matter
• Observation of Time-Dependent Internal Charge Amplification in a Planar Germanium Detector at Cryogenic Temperature