# Understanding Intra-day and Inter-day Variation in LIBS

FOSW03 - Statistical modelling of scientific evidence

Co-authors: Anjali Gupta (University of Auckland), Chris Triggs (Universtity of Auckland), Sally Coulson (ESR)

LIBS (laser induced breakdown spectroscopy) is a low-cost alternative and highly portable instrument that can be used in forensic applications to determine elemental composition. It differs from more traditional instruments such as ICP -MS and $\mu$-XRF in that the output is a spectrum rather than the concentration of elements. LIBS has great appeal in forensic science but has yet to enter the mainstream. One of the reasons for this is a perceived lack of reproducibility in the measurements over successive days or weeks. In this talk I will describe a simple experiment we designed to investigate this phenomenon, and the consequences of our findings. The analysis involves both classical methodology and a simple Bayesian approach.

This talk is part of the Isaac Newton Institute Seminar Series series.