Physical and dosimetric properties of NaCl pellets made in-house for the use in prospective optically stimulated luminescence dosimetry applications

NaCl pellets for prospective dosimetry using optically stimulated luminescence: Signal integrity and long-term versus short-term exposure

“…When dividing by a number which decreases with time, the estimated dose appears to increase with time. However, when D u is calculated using the signal-dose response curve taken from Waldner and Bernhardsson (2018), the estimated absorbed dose appears stable with time (Fig. 5d).…”

“…Based on these results, a preheat of 100 ºC was chosen for all further investigations. with time when calculated using a predetermined signaldose response curve (Waldner and Bernhardsson 2018). The rather large variability in Fig.…”

“…The integrated luminescence during the last 5 s of the recorded OSL signal decay curve was used as a background correction when further irradiations and readouts were performed on the same pellet since any additional induced signal will be added to the remaining background from the former readout. The calibration signal, S c , was thus defined as the integrated OSL signal between 0 and 5 s of readout corrected for the background of the previous OSL signal readout between 15 and 20 s. For some experiments, only Steps 1-3 of the readout protocol in Table 2 were used, and the signal was compared to the pre-established signal-dose response curve described in Waldner and Bernhardsson (2018). This curve shows the mean OSL signal from 10 NaCl pellets, read using Steps 1-3 of the protocol in Table 2, for several different increasing absorbed doses up to 300 mGy.…”

“…The reason for the change in OSL signal yield is not clear, but the compression of the salt during pellet production might be a factor, with point defects becoming instable due to the compression and then starting to stabilise after (Waldner and Bernhardsson 2018), as a function of time before readout (using either a pause "Pause", or a preheat protocol "PH" for Salts 1-3. Measurements were performed between 1 h and up to 36 days after irradiation, after a given dose (D u ) of 5 mGy.…”

“…Compressing the NaCl into pellets simplifies handling, improves reproducibility, and further supports the potential use of NaCl for prospective OSL dosimetry. Some of the dosimetric properties of NaCl in pellet form have already been investigated (Elashmawy 2018;Waldner and Bernhardsson 2018;Majgier et al 2019), but the use of NaCl pellets for long-term measurements outside the laboratory, e.g., for personal dosimetry or environmental monitoring, requires more knowledge and understanding regarding any potential changes in signal properties over time. Until now, most of the studies on NaCl pellets have only included results from acute radiation exposures, e.g., inside the reader.…”