[en] LiMgPO_4:Eu,Sm,B phosphors were synthesized using a solid-state diffusion synthesis method. Their optically stimulated luminescence (OSL) properties for real-time dosimetry were investigated, including thermoluminescence (TL), OSL emission spectrum, OSL dose response, OSL stimulation time and the reproducibility of the OSL signal. The LiMgPO_4:Eu,Sm,B phosphors exhibited high sensitivity to ionizing radiation, excellent signal stability for the tested period (up to 12 cycles) and a broad range of linear dose response (>0.1–540 Gy). The excellent luminescent and dosimetric properties of these LiMgPO_4:Eu,Sm,B phosphors make them promising candidates for real-time dosimeters with increased therapeutic efficacy and minimal toxicity. - Highlights: • A novel OSL material of LiMgPO_4:Eu,Sm,B phosphor is proposed for real-time dosimetry. • LiMgPO_4:Eu,Sm,B(LMP) exhibits good linearity in the dose range of 0.1–540 Gy. • LMP was found to be about 5 times that of LiMgPO_4:Tb,B in 0.1 Gy. • LMP exhibits a main TL peaks around 354 °C