Contents lists available at ScienceDirect Journal of Crystal Growth journal homepage: www.elsevier.com/locate/crysgro Luminescence and light yield of (Gd 2 Y)(Ga 3 Al 2 )O 12 :Pr 3+ single crystal scintillators Prapon Lertloypanyachai a,b , Nichakorn Pathumrangsan b , Krittiya Sreebunpeng f , Nakarin Pattanaboonmee a , Weerapong Chewpraditkul a, ⁎ , Akira Yoshikawa c,d , Kei Kamada d , Martin Nikl e a Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand b Muban Chombueng Rajabhat University, Ratchaburi 70150, Thailand c Institute f or Materials Research, Tohoku University, Sendai 980-8577, Japan d New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai 980-8579, Japan e Institute of Physics, AS CR, Cukrovarnicka´10, 162 53 Prague, Czech Republic f Chandrakasem Rajabhat University, Bangkok 10900, Thailand ARTICLE INFO Keywords: B1.(Gd 2 Y)(Ga 3 Al 2 )O 12 :Pr A1.Photoelectron yield A1.Luminescence A1.Scintillation ABSTRACT Praseodymium-doped (Gd 2 Y)(Ga 3 Al 2 )O 12 (GYGAG: Pr) single crystals are grown by the micro-pulling down method with different Pr concentrations. The energy transfer process between Pr 3+ and Gd 3+ is investigated by photoluminescence excitation (PLE) and emission (PL) spectra measurements. Photoelectron yield measure- ments are carried out using photomultiplier. At 662 keV γ-rays, photoelectron yield of 2520 phe/MeV obtained for the GYGAG: Pr (0.01%) sample is larger than that of 1810 phe/MeV obtained for BGO crystal. Light yield degradation for the GYGAG: Pr scintillators is presumably due to the energy transfer from 5d state of Pr 3+ to 4f state of Gd 3+ together with the concentration quenching in the Gd 3+ -sublattice. 1. Introduction Ce 3+ -and Pr 3+ -doped aluminum garnet crystals have been inten- sively studied and optimized to specific scintillator applications in the last two decades, see review in [1].Y 3 Al 5 O 12 :Ce and Lu 3 Al 5 O 12 :Ce crystals are good inorganic scintillators used for detection of X- and γ- rays due to fast scintillation response and good light yield [2,3]. The latest generation of Lu 3 Al 5 O 12 :Ce crystal shows light yield up to 25,000 pH/MeV [4,5] whereas the theoretical value of about 60,000 pH/MeV was estimated for the aluminum garnet scintillators [6]. It is due to the presence of shallow electron traps which delay the energy delivery to Ce 3+ centers and the scintillation pulse contains intense slow components [7,8]. Admixing Ga into the aluminum garnet host reduces trapping effects [9,10], and the thermal ionization of 5d 1 excited state of Ce 3+ center at room temperature can be reduced by the Gd admixture [11,12]. Thus, the recent studies focus on a material concept based on multicomponent garnet (Gd,Y, Lu) 3 (Ga, Al) 5 O 12 single crystal [11,13,14]. An improvement of the scintillator perfor- mance was achieved in Gd 3 Al 2 Ga 3 O 12 :Ce single crystal grown by the Czochralski method which show high LY of 46,000–50,600 pH/MeV [15,16]. However, the scintillation performance of Gd 3 Al 2 Ga 3 O 12 :Pr was degraded. Its light yield was only about 10% of the Cz grown Gd 3 Al 2 Ga 3 O 12 :Ce and accompanied by a high content of slow compo- nent in a scintillation decay (214 ns [98.8%]) [17]. The luminescence quenching in Pr 3+ -doped multicomponent garnet is ascribed to the non-radiative energy transfer pathway from Pr 3+ to Gd 3+ [18–20]. In this paper, we investigate the energy transfer process between Pr 3+ and Gd 3+ in the (Gd 2 Y)(Ga 3 Al 2 )O 12 :Pr single crystals. The absorption, photoluminescence emission (PL) and excitation (PLE) spectra are measured. The light yield measurements are carried out using photomultiplier (PMT) readout. All measurements are done at room temperature (RT). 2. Experimental details Pr 3+ - doped (Gd 2 Y)(Ga 3 Al 2 )O 12 (GYGAG: Pr) crystals were pre- pared by micro-pulling-down method (see details in Ref. [21]) with Pr concentration of 0.01, 0.1 and 0.5 at% at Institute for Materials Research, Tohoku University, Japan. Polished plates of 0.5 mm thick- ness cut from the parent crystals were used for all the measurements. Absorption spectra were recorded using a Perkin Elmer Lambda 35, UV-vis spectrophotometer. Photoluminescence emission (PL) and http://dx.doi.org/10.1016/j.jcrysgro.2016.10.018 Received 31 July 2016; Received in revised form 7 October 2016; Accepted 12 October 2016 ⁎ Corresponding author. E-mail address: weerapong.che@kmutt.ac.th (W. Chewpraditkul). Journal of Crystal Growth xx (xxxx) xxxx–xxxx 0022-0248/ © 2016 Published by Elsevier B.V. Available online xxxx Please cite this article as: Lertloypanyachai, P., Journal of Crystal Growth (2016), http://dx.doi.org/10.1016/j.jcrysgro.2016.10.018