On luminescent and scintillation properties of CsMgCl3:Eu2+ crystals

The paper reports results of pure CsMgCl3 and CsMgCl3:xEu2+ (x = 0.5, 1 and 1.5 mol. %, in the charge) single crystals growth and investigations of their functional properties. The crystals were grown by Bridgman method and the entry ratio of Eu2+ into CsMgCl3 was determined as 0.021, i.e. in all the europium-activated samples the concentration of the activator was at the level of admixtures. The photoluminescence spectra of CsMgCl3:Eu2+ show that Eu enters in the crystal both as Eu2+ form (main) and Eu3+ one (trace amounts). The shape of the spectra are dependent on excitation wavelength (λex): at λex=350 nm the shape of the spectra corresponds to those of Eu2+ activated halides (the maxima in 470–490 nm range) and at λex=275 nm the shape of spectra corresponds to those of Eu3+-activated phosphors. X-ray luminescence spectra include two bands with the maxima at 460 nm proper for Eu2+- activated halides and at 545 nm which could be ascribed to the distortions of CsMgCl3 crystal lattice due to entering of the slightly isomorphic Eu2+. The X-ray luminescence decay time is estimated within 0.8–0.9 µs. CsMgCl3:Eu2+ crystals possess the light yield of ca. 150 % vs. BGO (Bi4Ge3O12) and it is impossible to determine the concentration dependence since only traces of the activator are incorporated inside CsMgCl3:Eu2+ crystals. The best energy resolution is 18 %.