Safelight for OSL dating laboratories: a follow-up study

Abstract

We introduce a new lamp for use in optically stimulated luminescence (OSL) dating laboratories. The lamp is based on an LED with the peak emission wavelength at 594 nm that was previously characterised as safe for both samples and operators by Sohbati et al. (2017). We demonstrate that 48 h exposure to this lamp, delivering a power density of 0.2 µW.cm-2 at sample position, results in 1 ± 3 % loss in the infrared stimulated luminescence (IRSL) signal from clean K-rich feldspar grains. The loss in quartz OSL and K-feldspar post-IR IRSL signals is anticipated to be even smaller, given their lower bleaching rate at the lamp’s peak wavelength (i.e. 594 nm). We reiterate the conclusion by Sohbati et al. (2017) that the illumination provided by such a lamp is desirable for OSL dating laboratories.