Single-aliquot Regenerative-Dose (SAR) and Standardised Growth Curve (SGC) Equivalent Dose Determination in a Batch Model Using the R Package ‘numOSL’

Abstract

The single-aliquot regenerative-dose (SAR) protocol is widely used for determining equivalent dose (De) in optically stimulated luminescence (OSL) dating of Quaternary sediments. The standardised growth curve (SGC) method has been used as an efficient procedure to save measurement time for OSL measurements. The analysis of OSL signals and SAR data to determine De estimates and to establish SGC, however, usually involves a large amount of tedious work and is very time consuming, especially when a large number of aliquots or grains are measured and analysed. Here we present transparent and easy-to-use R functions to analyse OSL data sets obtained using SAR procedures in a batch model under the framework of the R package ‘numOSL’. These functions allow users to: (1) import and select data records from single or multiple BIN (or BINX) file; (2) analyse OSL signals and determine their standard errors, based on either a Poisson distribution or a non-Poisson (over-dispersed) distribution in counting statistics; (3) establish dose response curves (DRC) with a range of fitting functions, including a general order kinetic (GOK) function; (4) calculate SAR De and associated error using either a Monte Carlo simulation or a simple transformation method; (5) select reliable SAR De estimates based on a variety of rejection criteria; (6) select well-behaved DRCs to establish SGC using a least-square normalisation (LS-normalisation) procedure and calculate SGC De; (7) graphically summarise and report the results. Worked examples are provided to demonstrate the above functions using experimentally obtained data sets. The relevant R code templates are provided.