GSAG:Ce scintillator: insights from yttrium admixture.

Area of Science:

• Materials Science
• Solid State Physics
• Luminescence

Background:

• Gadolinium Scandium Aluminum Garnet doped with Cerium (GSAG:Ce) is a cost-effective scintillator alternative.
• Low light yield in GSAG:Ce has been attributed to thermal quenching.
• Yttrium (Y) admixture was investigated to enhance thermal activation energy and mitigate quenching.

Purpose of the Study:

• To investigate the effect of Yttrium (Y) admixture on the scintillation, optical, and luminescence properties of GSAG:Ce.
• To understand the correlation between Y content and performance characteristics like light yield and decay time.
• To identify the primary reasons for the low performance of GSAG:Ce scintillators.

Main Methods:

• Micro-pulling-down method for crystal growth of Gd_(3-Y Sc₂Al₃O₁₂:Ce (x = 0, 0.2, 0.5, 0.8).
• Temperature-dependent photoluminescence decay kinetics and thermally stimulated luminescence to quantify thermal quenching.
• Vacuum Ultraviolet (VUV) excitation spectroscopy using synchrotron radiation to assess energy transfer efficiency.

Main Results:

• Yttrium admixture did not significantly increase thermal activation energy or improve light yield in GSAG:Ce.
• Thermal ionization was ruled out as the main cause of low performance; scandium-related defects are implicated.
• Stoichiometric GSAG hosts exhibited higher light yield compared to congruent ones.

Conclusions:

• The strategy of Yttrium admixture is ineffective in suppressing thermal quenching and enhancing the performance of GSAG:Ce scintillators.
• Defects associated with scandium (Sc) play a crucial role in the suboptimal performance of GSAG:Ce.
• Further research into host stoichiometry and defect engineering is necessary for optimizing GSAG:Ce scintillator characteristics.