Shape-Controlled Crystal Growth of Y₃Al₅O₁₂:Ce Single Crystals with Application of Micro-Pulling-Down Method and Mo Crucibles, and Their Scintillation Properties

The technology to grow single crystals of the required shape directly from a melt has been researched extensively and developed in various industries and research fields. In this study, a micro-pulling-down method and a Mo crucible were applied to the shape-controlled crystal growth of Y<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula>Al<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>5</mn></msub></semantics></math></inline-formula>O<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>12</mn></msub></semantics></math></inline-formula>:Ce (YAG:Ce). Three types of Mo crucibles with different die shapes were developed. Stable crystal growth of more than 50 mm in length was achieved with the same shape as the die, and scintillation light output of ~20,000 ph/MeV, which is comparable with those of the YAG:Ce crystal grown by Cz method, were obtained. The transmittance of grown crystals above 500 nm was above 70%. The standard deviation (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>σ</mi></semantics></math></inline-formula>) of the scintillation light output at each position of the 50-mm-long sample was found to be within ±16%.