Performance of thin long scintillator strips of GSO:Ce, LGSO:Ce and LuAGiPr for low energy γ-rays

摘要

Interest in fibers or strips of single crystalline scintillators is increasing for their possible applications in fine-segmented particle detectors for particle physics experiments as well as γ-ray detectors for medical diagnoses. We compared 2 × 2 × 100 mm~3 strips of Gd_2SiO_5(GSO):Ce, Lu_(1.9)Gd_(0.1)SiO_5 (LGSO):Ce, and Lu_3Al_5O_(12)(LuAG):Pr single crystals for 0.511 MeV γ-rays with respect to the effective light attenuation length γ_a, light yield LY, FWHM energy resolution AE/E and rms position resolution σ(z) of the injection position z along the length. The obtained result was (λ_a LY, ΔE/E, σ(z))=(128 mm, 380 phe/MeV, 17.7%, 8.7 mm) in GSO:Ce, (509 mm, 1760 phe/MeV, 12.2%, 10.9 mm) in LGSO:Ce, and (171 mm, 690 phe/MeV, 15.0%, 8.9 mm) in LuAG:Pr. The z position was obtained independently from the pulse height ratio as well as the timing difference between both ends of the strip. The latter method gave comparable or even smaller σ(z) than the former only in LGSO:Ce having both large LY and fast rise time. The λ_a in the 100 mm long GSO:Ce strip was found to be twice as large as that in the 200 mm long one [1] with the same cross-section. To obtain good △E/E and σ(z), large light yield, fast rise time, and moderately large attenuation length are important for the scintillators.