Scintillation properties of CsBa2I5 activated with monovalent ions Tl+, Na+ and In+

We have previously reported the scintillation properties of CsBa2I5 activated with Eu2+, which exhibits excellent behavior [1,2]. The presence of Cs in the lattice makes CsBa2I5 a good candidate for activation with monovalent ions. We grew single crystals of CsBa2I5 with monovalent ions Tl, Na and In as activators. We performed a series of luminescence and scintillation measurements, including pulse height measurements using two different photosensors, on these crystals. We show not only that the monovalent ions are suitable activators in the chosen host lattice but also that the system has light yields between 33,000 and 40,000 ph/MeV, lower self-absorption than observed in Eu doped samples and excellent proportionality. The measured energy resolution on our initial samples of 7.1% FWHM for 662 keV gamma rays using avalanche photodiodes is very promising.