Analysis of neutron diffraction strain measurement data from a round robin sample

Abstract

Neutron diffraction strain data taken at 18 neutron facilities on a shrink-fit ring and plug round robin sample have been analysed using a Bayesian approach. The quality of data, quoted uncertainties and positional accuracy achieved are compared. Overall, the results of the exercise were consistent, and the majority of the laboratories obtained actual measurement uncertainties of 100με or less. The sample was measured under the auspices of the Versailles Project on Advanced Materials and Standards Technical Working Area 20 (VAMAS TWA 20), initiated to develop a recommended, standard procedure for making stress measurements in crystalline materials by neutron diffraction. This round robin study was carried out to determine the capabilities and reliability of the technique.