Scintillation Properties of 2-Inch-Diameter ${\rm Pr}:{\rm Lu}_{3}{\rm Al}_{5}{\rm O}_{12}$ (LuAG) Single Crystal

Abstract

Pr:LuAG crystals possess interesting properties, such as high density, high light yield, and very fast 5d-4f emission decay time. Recently, we developed a Pr:LuAG single crystal with a diameter of 2 inches for scintillator applications, such as medical imaging. In this study, Pr-doped Lu3Al5O12 (Pr:LuAG) single crystals with a diameter of 2 inches were grown by means of the Czochralski method; a body length of up to 90 mm was achieved. The Pr:LuAG crystals produced a homogeneous light yield with approximately 2.5 times less intensity compared to that produced by a conventional Ce:LSO crystal. A sample with dimensions of 5 mm times 5 mm times 1 mm exhibited energy resolutions of 4.8% at 662 keV, as measured by using a photomultiplier (PMT: Hamamatsu H6531), and 5.8% at 662 keV, as measured by using an Avalanche photodiode (APD: Hamamatsu S8664-55). The Pr:LuAG crystals exhibited a very fast rise time of approximately 0.4 ns, excited by a pulsed X-ray at room temperature. The decay time was approximately 18 ns, along with a noticeable presence of slower decay components (with a decay time of 55.0 ns). Furthermore, the Pr:LuAG crystals showed good linearity between the energy and pulse height within approximately 4% of the standard deviation in the range from 122 keV (152Eu) to 1.4 MeV (241Am) .