Investigation on thermally assisted optically stimulated luminescence (TA – OSL) signal in various sodium chloride samples

• Published in: Applied radiation and isotopes 2019-01, Vol.143, p.98-106
• Main Authors: Majgier, Renata, Biernacka, Magdalena, Palczewski, Piotr, Mandowski, Arkadiusz, Polymeris, George S.
• Format: Article
• Language: English
• Subjects: Dose response; Halite; Sodium chloride; Thermal assistance; Thermally-assisted optically stimulated luminescence; Very Deep traps
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2018.10.019

Sodium chloride (NaCl) is a phosphor with potential significance in retrospective dosimetry and geological dating. NaCl has been extensively studied for practical use in OSL dosimetry, however, the exact mechanism of the OSL emission is not well explained. This work attempts to extend the information on NaCl luminescent properties by establishing the occurrence of very deep traps in NaCl using the thermally assisted OSL (TA – OSL) method. The studied material was sodium chloride in different forms: halite minerals from Kłodawa salt mine in Poland and NaCl in chemically pure form. The isothermal TA – OSL signal was measured at various temperatures between 25 °C and 280 °C after a prior irradiation and TL erasing of shallow and main traps. The appearance of a strong TA – OSL signal indicates the occurrence of very deep traps in all forms of investigated salt. The temperature dependence of TA – OSL was determined and the activation energy for thermal assistance corresponding to deep traps in NaCl was estimated. For selected temperatures of TA – OSL readout (200 °C and 280 °C) the dose response was examined in wide dose range (1–1000 Gy). Sublinearity was found in different dose range depending on the type of samples. •Thermally-assisted OSL (TA – OSL) of sodium chloride (NaCl) was studied.•TA – OSL response of halite mineral and chemically pure NaCl crystals was compared.•The temperature dependence of the TA – OSL signal was determined.•The sublinear dose response of TA – OSL and TL was observed.