Extensive studies on light yield non-proportional response of undoped CeF3 at room and liquid nitrogen temperatures

In this paper properties of various undoped CeF3 scintillators were investigated at room and liquid nitrogen (LN2) temperatures. The study was focused on measurements of radioluminescence spectra, decay time, non-proportional response to X- and γ-rays, energy and intrinsic resolution at different temperature environment. Surprisingly, all the tested pure CeF3 crystals show non-proportional response up to 5.1 MeV gamma ray energy, which is contrary to the typical nonproportionality observed below 100 keV for most of the inorganic scintillators. The investigation of the phenomenon occurring in CeF3 scintillators would be another step to get a better knowledge of the scintillators nature, which still has not been entirely understood.