Measurement of 0.511 MeV γ-rays with a thin long strip of Gd2SiO5:Ce3+ scintillator

Scintillation characteristics of a thin long strip (2x2x200 mm3) of Gd2SiO5:Ce3+ 1.5 mol% single crystal was studied for 0.511 MeV γ-rays in order to examine the feasibility of fine-segmented γ-ray as well as charged particle detectors at low energies with good energy and position resolutions. From the pulse height and timing measurements at both ends, we obtained an energy resolution of 35-24% fwhm depending on position, and a position resolution of 10 mm rms almost independent of position. The attenuation of light yield with respect to the position z along the strip length is well fitted with a single exponential function exp(-z/λa) with an attenuation length λa=6.7±0.6 cm. The point injector of γ-rays worked excellently with negligible background. Possibility of application to axial PET scanners is also briefly discussed.