In this paper thermally stimulated luminescence (TSL) studies of K3Na(SO4)(2) phosphor are reported. A polycrystalline sample of K3Na(SO4)(2) was prepared by the solid state diffusion method. Formation of compound was checked by use of XRD and Fourier-transform infrared (FTIR) spectroscopy. The TSL glow curves of X-irradiated K3Na(SO4)(2) sample show one glow peak at temperature 170 degrees C indicating that only one set of traps is being activated within the particular temperature range each with its own value of activation energy (E) and frequency factor (s). The trapping parameters associated with the prominent glow peak of K3Na(SO4)(2) are calculated by using isothermal decay method. The release of hole/electron from defect centers at the characteristic trap site initiates the luminescence process in these materials. The intensity of the TL glow peaks increases with increase of the X-ray dose to the sample. (C) 2010 Elsevier B.V. All rights reserved.