Thermoluminescence properties and trap kinetics of SmCa4(BO3)3 phosphor

Abstract

Undoped SmCa4O(BO3)3 (SCOB) phosphor was synthesized by a microwave-assisted sol–gel combustion method and confirmed as single-phase monoclinic by X-ray diffraction. Thermoluminescence (TL) was measured after β-irradiation up to 500 Gy at a linear heating rate of 2 ◦C/s between room temperature and 450 ◦C. The glow curve at 50 Gy shows two main peaks at about 80 ◦C and 240 ◦C; after optimized preheating at 180 ◦C for 10 s, a single dominant peak near 247 ◦C remains and is used for all further measurements. The main peak shows good reusability over repeated readouts and a wide dose–response range from ~1 to about 500 Gy without saturation. Kinetic analysis of this peak using variable heating rate, initial rise, and glow-curve deconvolution yields activation energies around 1.6–1.8 eV and frequency factors of ~1014–1016 s 1, indicating a thermally stable trapping level suitable for dosimetric applications.