Luminescence of CsI:Na crystal scintillator under synchrotron radiation excitation

This work investigates the luminescence properties and energetic structure of emission centers created by NaCs isoelectronic impurities in a well-known CsI:Na scintillation crystal. Using synchrotron radiation excitation at 8 K, high-resolution spectroscopic techniques were employed to probe the electronic transitions and luminescent dynamics within the crystal. The study reveals distinct emission bands that can be attributed to both self-trapped exciton (STE) states and excitons bound to NaCs and defect-related centers, with a clear separation between fast and slow decay components. These findings provide deeper insight into how the NaCs impurity alters the emission behaviour of the CsI host, including modifications to energy transfer and relaxation processes