Crystal Growth and Characterization of Europium-Doped Rubidium Calcium Bromide Scintillators

National security strategies like gamma spectroscopy and high-energy X-ray radiography are limited, in part, by the scintillator used, prompting research into novel materials with improved properties. In this work, Eu $^{2+}$ activated rubidium calcium bromide scintillators were grown via the vertical Bridgman method with a range of dopant concentrations. Light yield, energy resolution, and the afterglow of Rb ₄ CaBr ₆ :Eu and RbCaBr ₃ :Eu improved with increasing Eu $^{2+}$ concentration, and scintillation decay time increased. The highest light yields of Rb ₄ CaBr ₆ :Eu and RbCaBr ₃ :Eu were 71000 and 45000 ph/MeV, respectively.