CC BY
9¡±112_^ ALT'22
LASER SYSTEMS AND MATERIALS
Influence of Sc on luminescence properties of GAGG:Ce scintillator
D. Spassky1, O. Buzanov2, N. Kozlova3, V. Kasimova3, E. Zabelina3
1 - Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, Russia 2 - FOMOS-Materials, Moscow, Russia 3 - National University of Science and Technology MISiS, Moscow, Russia
zabelina.ev@misis.ru
Gd3Al2Ga3O12:Ce3+ (CAGG:Ce) is a high-density and chemically stable compound with scintillation yield up to 60000 ph/MeV, which is promising for application as a scintillator in medicine (SPECT, PET) and high-energy physics [1]. The main disadvantage of this crystal is the presence of slow decay components. Along with the typical for the 5d-4d Ce3+ emission decay component ~60 ns additional slow components with t > 200 ns appear in the scintillation response, which deteriorate the scintillation performance [2]. The presence of slow decay components is related to the energy migration via the Gd sublattice as well as to intermediate localization of charge carriers at traps.
The method of bandgap engineering allows fine tailoring of physical properties by gradual change of crystal composition [3]. Previously it was shown by us that partial substitution of Al and Ga cations by Sc in GAGG:Ce crystals considerably change the conduction band structure in garnets due to the contributions of the electronic states of Sc [4]. For that reason, the modification of cation composition by partial substitution of the Al and Ga cations with Sc is expected to influence the relaxation of high-energy excitations and energy transfer to Ce3+ emission centers in GAGG:Ce crystals. Here we present the study of the influence of Sc on luminescence properties of GAGG:Ce. The modification of luminescence decay curves will be in the focus of the study.
The influence of Sc on the electronic band structure of GAGG:Ce and the energy of the 4f and 5d Ce3+ levels is shown. It is shown that the modification of the band structure induced by the Sc electronic states results in the suppression of Gd emission and enhancement of Ce3+ emission at low temperatures. The influence of Sc incorporation into GAGG:Ce crystal on decay kinetics of Ce3+ emission was studied under excitation in the region of intranceter Ce3+ and Gd3+ excitation as well as in the region of direct exciton formation, Sc - related excitation band and at high-energy excitation. It is shown that Sc accelerates energy transfer to Ce3+ emission centers. The origin of the observed effects is discussed in the presentation.
Financial support from the grant RFBR 20-02-00688 is gratefully acknowledged.
[1] P. Lecoq, Development of new scintillators for medical applications, Nucl. Instrum. Meth. A, 809 (2016) 130-139.
[2] K. Kamada, M. Nikl, Sh. Kurosawa, A. Beitlerova, A. Nagura, Y. Shoji, J. Pejchal, Y. Ohashi, Y. Yokota, A. Yoshikawa, Alkali earth co-doping effects on luminescence and scintillation properties of Ce doped Gd3Al2Ga3O12 scintillator, Opt. Mater., 41 (2015) 63-66.
[3] M. Nikl and A. Yoshikawa, Recent R&D Trends in Inorganic Single-Crystal Scintillator Materials for Radiation Detection, Adv. Opt. Mater., 3 (2015) 463-481.
[4] D. Spassky, N. Kozlova, E. Zabelina, V. Kasimova, N. Krutyak, A. Ukhanova, V.A. Morozov, A. V. Morozov, O. Buzanov, K. Chernenko, S. Omelkov, V. Nagirnyi, Influence of Sc cation substituent on structural properties and energy transfer processes in GAGG:Ce crystals, CrystEngComm 22, 2621 - 2631 (2020).
