Improvement of γ-ray energy resolution of LaBr_3∶Ce~(3+) scintillation detectors by Sr~(2+) and Ca~(2+) co-doping

摘要

Commercially available LaBr_3∶5% Ce~(3+) scintillators show with photomultiplier tube readout about 2.7% energy resolution for the detection of 662 keV γ-rays. Here we will show that by co-doping LaBr_3∶Ce~(3+) with Sr~(2+) or Ca~(2+) the resolution is improved to 2.0%. Such an improvement is attributed to a strong reduction of the scintillation light losses that are due to radiationless recombination of free electrons and holes during the earliest stages (1-10ps) inside the high free charge carrier density parts of the ionization track.