Study of LaCl3:Ce light yield proportionality with a hybrid photomultiplier tube

In these years a great interest has been growing for the cerium-doped lanthanum crystals due to their high scintillation yield well-matched to present photocathodes, which makes them promising for nuclear medical imaging. In this paper we report on the LaCl3:Ce scintillation response, with the aim to evaluate its degree of non-proportionality. Light yields of LaCl3:Ce, expressed in photoelectron numbers, were measured for X-ray and γ -energies ranging between 13.4 and 1332 keV . In the same energy range, the energy resolution was also measured. The test was performed with a 25 × 25 × 3 mm 3 crystal mounted on a Hybrid Photomultiplier Tube (HPMT) PP0470 by DEP. We observed the presence of two different ranges of LaCl3:Ce light yield response, respectively, for energies higher than 22Na- 511 keV and for energies lower than 57Co- 122 keV . A sensible difference of light yield was observed in these two regions.