Simulated annealing analysis of nuclear reaction analysis measurements of polystyrene systems

Nuclear reaction analysis (NRA) is a standard technique in compositional analysis of materials, including depth profiling of elements. It is particularly useful for the profiling of deuterium in polymers. However, the data analysis can be cumbersome and time-consuming. In this paper we present fully automated analysis of NRA data using the simulated annealing combinatorial optimization algorithm. The routine is general and can be used to analyse data from any reaction with known Q value and cross section. The shape of the cross section is taken into account, and hence depth profiling using reactions with non-hat cross sections can be done in a trivial way. Furthermore, the algorithm allows one to take into account the degradation of energy resolution with probing depth, which is shown to be crucial in analysing thin layers, where the depth resolution is a determining factor. We have also shown that we can calculate confidence limits on the depth profiles obtained by using Bayesian inference with the Markov chain Monte Carlo method. We present the application of the algorithm to the analysis of deuterated polystyrene samples.