Origin of the ~1 μs infrared scintillation decay in gaseous xenon

Determine the origin of the approximately 1 microsecond infrared scintillation decay constant observed in gaseous xenon, as seen in both alpha-induced emission and electroluminescence, and identify the underlying physical mechanism responsible for this component.

Background

The study reports infrared emission in a dual-phase xenon TPC coincident with UV scintillation for both prompt (S1) and electroluminescence (S2) signals. Time-response analysis in gas reveals multiple components, including a fast (few-ns) and intermediate (~1.7 μs) decay, and a new slow (~30 μs) component. In addition to these, a ~1 μs IR decay constant in gas has been seen here and previously.

The authors note that the ~1 μs IR component does not obviously correspond to known UV scintillation processes, suggesting it may arise from an alternative de-excitation pathway. Clarifying the physical origin of this ~1 μs decay is important for interpreting IR scintillation and assessing potential uses in particle identification and detector performance.