Improvement of X-ray excited luminescence properties of Mg4Ta2O9 scintillators by rare-earth doping.

Hexagonal-structure Mg 4 Ta 2 O 9 (MTO) powders doped by 0.25 at% RE (RE = La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3 +, Yb3+, Lu3+, Y3+, Sc3+) were synthesized. All the rare earth-doped samples were checked by X-ray diffraction (XRD) and confirmed to be monophasic powders. Among them, Mg 4 Ta 2 O 9 doped by 0.25 at% Gd3+ and Sc3+ had higher X-ray excited luminescence (XEL) emission peak intensities, 3.05 and 2.79 times of MTO, respectively. The optimal concentrations of Gd3+ and Sc3+ were investigated based on XEL main emission peak intensity changing with the amount of dopants in the range of 0∼1.0 at%. The optimal XEL emission peak intensities were measured 3.32 and 3.09 times of MTO for MTO: 0.8 at% Gd3+ and MTO: 0.4 at% Sc3+, respectively. The photoluminescence (PL) emission peaks at around 370 nm correspond to two excitation peaks at 158 and 215 nm. The excitation peak at 158 nm is about 10 times more than that of at 215 nm in intensity. The emission spectra excited by vacuum ultraviolet light at 158 nm and ultraviolet light at 215 nm were investigated associated with scintillation emission mechanism. MTO: 0.8 at% Gd3+ and MTO: 0.4 at% Sc3+ show potential application in security inspection, industrial detection, etc. • Single-phase Mg 4 Ta 2 O 9 : 0.25 at% RE (RE = La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3 +, Yb3+, Lu3+, Y3+, Sc3+) samples were synthesized. • Single-phase Mg 4 Ta 2 O 9 : x at% M (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0; M = Gd3+, Sc3+) samples were synthesized. • MTO: 0.8 at% Gd3+ among MTO: x at% Gd3+ and MTO: 0.4 at% Sc3+ among MTO: x at% Sc3+ have the highest excitation peaks at 158 and 215 nm. • MTO: 0.8 at% Gd3+ and MTO: 0.4 at% Sc3+ have highest relative main XEL emission peak intensities of 3.27 and 3.09 times of MTO, respectively. • The scintillation emission mechanism of improving XEL properties of Mg 4 Ta 2 O 9 scintillators by rare-earth doping is thoroughly analyzed. [ABSTRACT FROM AUTHOR]