Speaker
Description
Detecting the deep VUV scintillation light from noble elements such as argon (128 nm) and xenon (178 nm) remains a major challenge in fully realizing the physics potential of modern dark matter and neutrino detectors. Existing direct detection technologies (cryo VUV SiPMs and PMTs) typically achieve efficiencies below 20%. In this talk, we present the first comprehensive characterization of windowless, laterally structured amorphous selenium (a-Se) photodetectors engineered for direct VUV sensitivity and stable operation at cryogenic temperatures.
We demonstrate that these devices exhibit remarkable stability and sensitivity across a wide temperature range (77–290 K) and electric fields approaching avalanche conditions.The detectors achieved single-shot detection efficiencies approaching 65% with as few as 100 field-effective 401 nm photons at 165 K, illustrating their sensitivity to such low-level optical excitation. At 87 K, the prototypes maintained a similar functional behavior under direct VUV illumination at 130 nm, showing for the first time that the avalanche response mechanism remains active at cryogenic temperature and across excitation wavelengths relevant to noble elements scintillation. Complementary studies with tellurium-doped a-Se (a-SeTe) reveal avalanche onset at reduced fields and enhanced gain, pointing to a powerful direction for future optimization.
Our new photosensors prototypes offers a compelling combination of cryogenic compatibility, wide dynamic range, low-photon sensitivity, and VUV response—paving the way for scalable, high-field-compatible photodetection systems in next-generation dark matter and neutrino detectors.
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