High-purity germanium (HPGe) detectors are among the most powerful instruments for gamma ray spectroscopy, combining exceptional energy resolution with large active volumes. Although they operate close to the fundamental resolution limit at high energies, their performance at very low energies has long been limited by electronic noise, restricting detection thresholds to above approximately 30 electron-hole pairs ($\sim$100 eV). Here we introduce a cryogenic HPGe detector architecture that achieves single electron-hole pair sensitivity by calorimetrically measuring ionization at temperatures near 20 mK. The device integrates a NbSi transition-edge sensor into a point-contact-inspired geometry, concentrating athermal phonon energy generated during charge drift and enabling eV-scale sensitivity ultimately set by the semiconductor band gap. Beyond single-charge detection, the device rejects the low-energy excess background that limits existing cryogenic low-threshold technologies, establishing a pathway towards discrimination between electron- and nuclear-recoil events below 100 eV. These advances open a route towards next-generation detectors for direct dark matter searches, coherent elastic neutrino-nucleus scattering, and nuclear reactor monitoring for non-proliferation applications.
Intrinsic sensitivity is a key parameter for vacuum Compton detectors (VCDs), enabling the quantitative analysis of pulsed γ-radiation fields. Since VCDs are insensitive to the emitted electron energy, traditional calibration of intrinsic sensitivity has generally neglected the contribution of low-energy electrons. In...
Zong-Xiang Ma, Peng Xu, X. Guan et al.· Journal of Instrumentation· 0 citations
A defining trend in modern electron microscopy is the shift toward low-energy, low-current techniques to facilitate non-destructive, in-situ analysis at the frontiers of science. This work presents a novel strategy based on wide band-gap 4H-SiC for sensitive direct electron detection, featuring an ultra-thin Schottky e...
Ren-Jie Xu, Jie Jin, Lin Zhang et al.· IEEE Electron Device Letters· 0 citations
Hybrid pixel detectors represent the state-of-the-art technology for hard X-ray experiments at synchrotron light sources and free-electron lasers, owing to their high frame rates, extended dynamic range, and scalable detection areas. However, their application in the soft X-ray regime remains bottlenecked by the challe...
Shu-Qi Li, Anna Bergamaschi, Ashish Bisht et al.· 0 citations
The far-infrared (FIR) foreground level in space is extremely low, necessitating highly sensitive detectors for space-based continuum observations. To achieve photon-noise-limited performance, FIR detectors require a noise equivalent power (NEP) lower than 3 ×10 −19 W Hz −1/2 and a per-pixel saturation power ( Psat) ra...
Ling-Mei Zhang, Jia-Min Sun, Lin Zhu et al.· Superconductors Science and...· 0 citations
Rare-earth elements are key components in a wide range of functional materials, including solid-state lasers, superconductors and high-performance permanent magnets, owing to their localized 4f electrons that give rise to distinctive electronic and magnetic properties. Nuclear resonant scattering of synchrotron radiati...
Sven Velten, Deepak Prajapat, F. Dill et al.· Journal of Synchrotron Radia...· 0 citations
Sensor noise is a fundamental barrier to low-flux astronomical imaging and spectroscopy, where the ideal sensor would unambiguously distinguish individual photon arrivals. While optical semiconductor arrays can reach single-photon sensitivity, comparable performance in the infrared has largely required superconducting...
Guillaume Huber, P. Bilgi, Charles-Antoine Clàveau et al.· 0 citations
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