Development of low-threshold detectors for low-mass dark matter searches with a p-type germanium detector operated at cryogenic temperature

TL;DR

This research advances low-threshold detection technology for low-mass dark matter by analyzing charge transport in p-type germanium detectors at cryogenic temperatures, focusing on binding energies and trapping cross-sections.

Contribution

It introduces new measurements of dipole and cluster dipole state binding energies at cryogenic temperatures and compares different detector cooling modes for improved sensitivity.

Findings

Lower binding energies observed in direct cooling mode.

Measured dipole and cluster dipole binding energies at zero field.

Implications for designing more sensitive low-mass dark matter detectors.

Abstract

This study investigates new technology for enhancing the sensitivity of low-mass dark matter detection by analyzing charge transport in a p-type germanium detector at 5.2 K. To achieve low-threshold detectors, precise calculations of the binding energies of dipole and cluster dipole states, as well as the cross-sections of trapping affected by the electric field, are essential. The detector was operated in two modes: depleted at 77 K before cooling to 5.2 K and cooled directly to 5.2 K with various bias voltages. Our results indicate that the second mode produces lower binding energies and suggests different charge states under varying operating modes. Notably, our measurements of the dipole and cluster dipole state binding energies at zero fields were $8.716\pm 0.435$ meV and $6.138\pm 0.308$ meV, respectively. These findings have strong implications for the development of low-threshold detectors for detecting low-mass dark matter in the future.