Applied Physics A manuscript No. (will be inserted by the editor) Depth-dependent calibration for quantitative elemental depth profiling of copper alloys using Laser Induced Plasma Spectroscopy Juri Agresti · Salvatore Siano Received: 2/11/2013 / Accepted: 4/3/2014 Abstract This work presents new calibration procedures for deep elemental depth profile analysis of bronze artifacts. A simple ablation model is developed for the es- timation of the ablation rate and hence for deriving the depth spatial calibration scale. Elemental quantification is obtained through the construction of calibra- tion surfaces, using reference samples of known composition, relating laser-induced plasma spectroscopy (LIPS) intensity ratios, content of atomic species and num- ber of laser pulses. Such a method represents a refinement of the standard LIPS quantification approach based on calibration curves, which is extended here to the generation of significantly deep craters into the material under investigation up to several hundred microns. The depth dependence of the calibration surfaces measured is discussed in the framework of a simplified model of depth-dependent plasma temperature. Keywords Depth profile · Laser Induced Plasma Spectroscopy · Laser ablation · copper alloys 1 Introduction Among the unique advantages of laser-induced plasma spectroscopy (LIPS) there is the possibility of measuring the content of a given analyte as a function of the number of laser pulses released to the target and hence of the associated abla- tion depth. In particular, LIPS capabilities in depth profile analysis are of great interest for a number of cases requiring appropriate methods for determining com- positional variations in proximity of the sample surface, such as those of coated materials, in the industrial field [1,2], as well as those of multilayer surface finish- ing or weathered artifacts in the cultural heritage conservation [3,4]. The latter often requires relatively deep analytical profiling as we have shown for example by approaching authentication problems of copper alloy and ceramic artifacts [5]. The J. Agresti · S. Siano Istituto di Fisica Applicata Nello Carrara - CNR, Sesto Fiorentino (FI), 50019, Italy Tel.: +39-055-5225329 E-mail: j.agresti@ifac.cnr.it The final publication is available at Springer via http://dx.doi.org/10.1007/s00339-014-8363-x