Time- and energy-resolution measurements of BaF_2, BC-418, LYSO and CeBr_3 scintillators

摘要

We have investigated the time and energy resolution (T_(Timing), ΔE/E) of four different scintillator materials BaF_2, BC-418, LYSO and CeBr_3 at a gamma energy of 511 keV in views of their possible usage for time, energy and position resolution for positron annihilation experiments. The shape of each scintillator was a cylinder with a diameter of 25 mm and a height of 10 mm readout by a Photonis XP2020/URQ photomultiplier tube. The best single time resolution was determined for each photomultiplier-scintillator setup in a three step optimization process. The optimized single time resolutions (FWHM) for BaF_2, BC-418, LYSO and CeBr_3 were 119 ps, 117 ps, 269 ps and 127 ps, respectively. We measured the energy resolution of the photomultiplier-scintillator setups which show a photopeak in the energy spectrum. The energy resolutions ΔE/E of BaF_2, LYSO and CeBr_3 were 9.8%, 9.7% and 5.4%, respectively. The overall most promising material for measuring simultaneously time, energy and position resolution for positron annihilation experiments seems to be CeBr_3 due to its very good time and energy resolution characteristics.