Optically stimulated luminescence, thermoluminescence and photoluminescence characteristics of SrB₄O₇:Eu phosphor

SrB₄O₇:Eu³⁺ (0.1-1.0 M%) phosphor materials were synthesized by solid-state diffusion method. Effects of doping concentration, annealing in oxidizing and reducing atmospheres and phase transitions on the luminescence properties of SrB₄O₇:Eu³⁺ phosphor were investigated. Thermoluminescence (TL) study of the SrB₄O₇:Eu³⁺ (0.2 M%) phosphor material revealed excellent properties, such as, simple glow curve (not changing its structure on irradiation for different doses), high sensitivity (3.6 times more intense than TLD-100 and approximately equal to the intensity of TLD-900), wide and linear dose response (0.5 Gy to 5.0 kGy), good reusability, etc. However, there is high TL fading, which may be occurring due to quantum tunnelling between the defects (traps/luminescence centers) related to Eu²⁺ and Eu³⁺ impurity ions. Dosimetry study using CW-OSL technique of SrB₄O₇:Eu³⁺ (0.6 M%) was also explored. The phosphor shows similar dosimetry properties like linear CW-OSL dose response (100.0 Gy to 10.0 kGy) but low fading (just 20% in 60 days). Different fading patterns show that the traps involved in the luminescence processes could be different though the material exhibit two different kinds of luminescences. The phosphor material has good dosimetry properties and it could be used as potential TLD as well as OSLD phosphor for dosimetry applications. (author)