Radiation Physics and Chemistry xxx (xxxx) xxx Please cite this article as: Miriam Saleh et al., Radiation Physics and Chemistry, https://doi.org/10.1016/j.radphyschem.2023.111298 Available online 26 September 2023 0969-806X/© 2023 Elsevier Ltd. All rights reserved. Analysis probes and statistical parameters affecting the OSL ages of mortar samples; a case study from Italy Miriam Saleh a, * , Georgios S. Polymeris b , Laura Panzeri a , Efstathios Tsoutsoumanos b, c , Giulia Ricci d, e , Michele Secco d, f , Marco Martini a , Gilberto Artioli d, e , Simone Dilaria d, f , Anna Galli a a Department of Materials Science, Universit` a degli Studi di Milano-Bicocca, Milan, Italy b Institute of Nanoscience and Nanotechnology, National Centre for Scientifc Research “Demokritos”, Athens, Greece c Condensed Matter Physics Laboratory, Physics Department, University of Thessaly, Lamia, Greece d Inter-Departmental Research Centre for the Study of Cement Materials and Hydraulic Binders (CIRCe), University of Padova, Padua, Italy e Department of Geosciences, University of Padova, Padua, Italy f Department of Cultural Heritage (DBC), University of Padova, Padua, Italy A R T I C L E INFO Handling Editor: Piotr Ulanski Keywords: OSL dating Mortars dating Descriptive statistic Luminescence ABSTRACT Mortars stand among the very few materials that theoretically cannot be reused due to irreversible hardening processes. Among the various dating techniques, radiocarbon and Optically Stimulated Luminescence (OSL) struggle for being selected as the most robust and reliable dating technique for the specifc material. The prin- ciple of mortar OSL dating depends on the bleaching of the quartz grains of the sandy aggregate while mixing and laying the mortar to daylight. Thus, the OSL ages strongly depend on the effective bleaching of the quartz. Here, we deal with OSL ages from the old Roman Theatre of Padua. Preliminary OSL results based on Single Aliquot Regeneration (SAR) protocol using three regenerated doses to multigrain (MG) quartz aliquots, indicated dis- tributions of ED (Equivalent Dose) leading to signifcant mismatch of these results compared to the expected ages. The present work attempts to discuss the infuence of various data analysis approaches such as (a) exclusion criteria like recycling ratio and recuperation values, (b) selection of the suitable region of interest in the signal’s integral along with the correct background (late or early) subtraction technique and (c) appropriate statistical analysis by selecting the suitable age model (descriptive statistics, Central Age Model, Minimum Age Model) on the fnal distribution as well as both value and precision of the ED, enabling thus to obtain ages that are not only more accurate, but also closer to what was expected. Alternative statistical indicators of either the symmetry of the ED distributions (like skewness, kurtosis, etc) or the OSL signal itself (residual distribution analysis, kinetic parameters and percentage contribution of each OSL component to the overall signal) will be assessed in an effort to investigate possible correlations. 1. Introduction Luminescence dating methods such as thermoluminescence (TL) and optically stimulated luminescence (OSL) are useful tools for age deter- mination in historic buildings. The former dates the last heating while the latter dates the last exposure to light of the wall material. TL is the most widespread and consolidated dating method for ceramics, bricks, terracotta, porcelain, kilns, burn fints, etc. However, materials dated by TL can be frequently reused (Aidona et al., 2018; Galli et al., 2020; Guibert et al., 2012; Martini and Sibilia, 2006) and there is always the risk that the age is not contemporary with the construction of the archaeological building under study. Nowadays, dating of mortars is recognized as one of the possible solutions for dating historic buildings. Dating mortars has one advan- tage: a mortar is produced once and exclusively for the building under analysis. Furthermore, among all materials found in a building (metal, wood, brick, binder and stone), mortar is the only one that cannot be in principle reused due to its irreversible hardening process. The frst po- tential dating technique for this material was radiocarbon dating. Once the lime binder has been laid, it is assumed that the carbonation process * Corresponding author. E-mail address: m.saleh1@campus.unimib.it (M. Saleh). Contents lists available at ScienceDirect Radiation Physics and Chemistry journal homepage: www.elsevier.com/locate/radphyschem https://doi.org/10.1016/j.radphyschem.2023.111298 Received 14 April 2023; Received in revised form 26 July 2023; Accepted 24 September 2023