LPE Growth of Single Crystalline Film Scintillators Based on Ce3+ Doped Tb3−xGdxAl5−yGayO12 Mixed Garnets

Vitalii Gorbenko,Sandra Witkiewicz,Tetiana Zorenko,Yuriy Zorenko,Paweł Bilski,Alexander Fedorov,Oleg Sidletskiy,Kazimierz Paprocki,Anna Twardak

doi:10.3390/cryst7090262

Abstract

The growth of single crystalline films (SCFs) with excellent scintillation properties based on the Tb1.5Gd1.5Al5−yGayO12:Ce mixed garnet at y = 2–3.85 by Liquid Phase Epitaxy (LPE) method onto Gd3Al2.5Ga2.5O12 (GAGG) substrates from BaO based flux is reported in this work. We have found that the best scintillation properties are shown by Tb1.5Gd1.5Al3Ga2O12:Ce SCFs. These SCFs possess the highest light yield (LY) ever obtained in our group for LPE grown garnet SCF scintillators exceeding by at least 10% the LY of previously reported Lu1.5Gd1.5Al2.75Ga2.25O12:Ce and Gd3Al2–2.75 Ga3–2.25O12:Ce SCF scintillators, grown from BaO based flux. Under α-particles excitation, the Tb1.5Gd1.5 Al3Ga2O12:Ce SCF show LY comparable with that of high-quality Gd3Al2.5Ga2.5O12:Ce single crystal (SC) scintillator with the LY above 10,000 photons/MeV but faster (at least by 2 times) scintillation decay times t1/e and t1/20 of 230 and 730 ns, respectively. The LY of Tb1.5Gd1.5Al2.5Ga2.5O12:Ce SCFs, grown from PbO flux, is comparable with the LY of their counterparts grown from BaO flux, but these SCFs possess slightly slower scintillation response with decay times t1/e and t1/20 of 330 and 990 ns, respectively. Taking into account that the SCFs of the Tb1.5Gd1.5Al3–2.25Ga2–2.75O12:Ce garnet can also be grown onto Ce3+ doped GAGG substrates, the LPE method can also be used for the creation of the hybrid film-substrate scintillators for simultaneous registration of the different components of ionization fluxes.

Highlights

The development of detectors for 2D/3D microimaging using X-ray sources and synchrotron radiation demands the creation of thin single crystalline film (SCF) scintillating screens with an extremely high ability for X-ray absorption and a micron-submicron spatial resolution [1,2,3,4]. For this purpose, the visible emitting scintillating screens based on the SCF of Ce doped Y3 Al5 O12 (YAG) and Lu3 Al5 O12 (LuAG) garnets grown by the Liquid Phase Epitaxy (LPE) method have been used and the spatial resolution of the detector in the micron range has been achieved using synchrotron radiation with energy in the
By using such multilayer-film scintillators one can significantly improve the contrast and resolution of images even in the submicron range. Two such novel concepts demand the fabrication of different sets of heavy and efficient SCF scintillators which can be deposited onto the same substrates
We report the creation of advanced single crystalline film (SCF) screens with excellent scintillation properties based on the Tb1.5 Gd1.5 Al3–2.5 Ga2–2.5 O12 :Ce mixed garnet compounds grown by the LPE method from both novel lead free BaO and traditional PbO based fluxes onto Gd3 Al2.5 Ga2.5 O12 (GAGG) substrates

Summary

Introduction

The development of detectors for 2D/3D microimaging using X-ray sources and synchrotron radiation demands the creation of thin (from a few microns thick up to 20 microns) single crystalline film (SCF) scintillating screens with an extremely high ability for X-ray absorption and a micron-submicron spatial resolution [1,2,3,4]. By using such multilayer-film scintillators one can significantly improve the contrast and resolution of images even in the submicron range Two such novel concepts demand the fabrication of different sets of heavy and efficient SCF scintillators which can be deposited onto the same substrates. Other sets of optically good quality Tb1.5Gd1.5Al5−yGayO12:Ce SCF samples—with y values onto GAGG substrates from novel lead-free BaO based flux X-ray imaging [6,7,18,19]

Images of undoped

O12 :Ce

Luminescent and Scintillation xAl

Cathodoluminescence Spectra

Normalized

TSL Properties

Photoelectron

Findings

Conclusions