[20p-224B-1~8] 2.1 放射線物理一般・検出器基礎

▲ [20p-224B-5] The effect of Li and Mg codoping strategy on the properties of Gd₃Ga₃Al₂O₁₂ single Crystal scintillators

〇(P)Karol Bartosiewicz^1,2、Akira Yoshikawa^1,3,4、Shunsuke Kurosawa^1,3,5、Akihiro Yamaji¹、Martin Nikl⁶ (1.Tohoku University, IMR、2.KW University, IP、3.Tohoku University, NICHe、4.C&A corporation、5.Yamagata University, FS、6.ASCR, IP)

キーワード：Multicomponent Garnets, Single Crystal, Ce4+

The Ce³⁺ activated Gd₃Ga₃Al₂O₁₂ (GGAG) single crystals are promising candidates for the next generation of the efficient material for scintillator applications, due to very good chemical and physical properties such as high light yield, high density, fast decay time and non-hydroscopic [1]. However, this material suffers from the contribution of the undesired slow component in the scintillation response [2] and long rise time [3]. Recently, the divalent (Me²⁺) and monovalent (Me⁺) codoping strategy has been used in order to mitigate the degraded scintillation properties that result from charge carrier traps and have been shown to improve light yield and decay times in some scintillators [4].
The motivation for this work comes from the positive impact of stable Ce⁴⁺ in the GGAG:Ce scintillators. We study the effect of the concentration ratio of Li⁺, Mg²⁺ and Ce³⁺ in the GGAG crystals on the scintillation and luminescence performance, which is strongly dependent on the stable Ce³⁺/Ce⁴⁺ content ratio. The GGAG single crystals with a various dopant (Ce³⁺) and codopants (Li⁺, Mg²⁺) content were grown from the melt by the micro-pulling-down method. They were characterized by optical absorption, photoluminescence excitation and emission and photoluminescence decay kinetic measurements. Scintillation properties of the crystals were studied by means of light yield value and scintillation decay time analysis.
[1] M. Nikl, A. Yoshikawa, Adv. Optical Mater. 3 (2015) 463-481
[2] K. Kamada et al., Cryst. Growth Des. 11 (2011) 4484-4490
[3] M. Lucchini et al., Instr. Meth. Phys, Research A 852, (2017) 1-9
[4] C. Foster et al., J. Cryst. Growth, in press (10.1016/j.jcrysgro.2018.01.028)