Radio- and thermoluminescence of single-doped and codoped lithium-sodium sulfate

Abstract

Radioluminescence at room temperature and thermoluminescence (TL) measurements of single-doped and codoped LiNaSO₄ above room temperature are reported here. The codoped samples were studied to investigate the possibility of enhancing the TL sensitivity of LiNaSO₄:Eu. This objective was not satisfied and the codopants (Ce, Sm, Ho and Er) decrease the TL sensitivity and slightly shift the dosimetric peak to lower temperatures. Samples doped with Mg, K, Bi and Tl were used with the hope that they may alter the trapping centers stability and introduce new peaks in the temperature range 430–500 K to observe any TL discontinuity or wavelength shift in their spectra as observed in CL measurements. This objective was fulfilled with Tl and Bi, where there is a discontinuity and/or wavelength shift at about 460 K. Such intensity and/or wavelength variations are ascribed to microstructural phase changes within the LiNaSO₄ crystals that may result from twin boundaries behaving like Na₂SO₄.

Keywords:

• thermoluminescence
• radioluminescence
• LiNaSO₄
• twin boundaries

Acknowledgment

One of us (MM) wishes to thank the Hashemite University for the financial support.