C. W. E. van Eijk, P. Dorenbos, E. V. D. van Loef, K. Krämer and H. U. Güdel
Energy resolution of some new inorganic-scintillator gamma-ray detectors
Rad. Meas. 33, 521-525 (2001)                 

Abstract: The question whether the energy resolution of inorganic-scintillator gamma-ray detectors can be improved, particularly at gamma-ray energies above ~300 keV is addressed. Experimental results presented on the new scintillators LaCl₃:Ce and LaBr₃:Ce demonstrate that the answer is confirmatory. At 662 keV, energy resolutions of respectively, 3.1% and 3.0%, were observed.