Correction of a neutron diffraction peak shift due to a partial immersion of a gauge volume in an unstressed sample

There exists an effect of variation of peak positions measured by neutron diffraction if the gauge volume is only partially immersed in a sample. In literature, this diffraction peak shift is known as pseudostrain or surface effect. The correction of the peak position on the pseudostrain effects may be made by analytical calculation or Monte Carlo simulation. We have developed a reductive analytical approach to account for the pseudostrain effect in a thin-walled sample using a concept of pseudo-time introduced by Creek et al. [4] for time-of-flight (TOF) neutron diffraction experiments. The approach was verified on the diffraction experimental data obtained by two groups of researchers [1,2] with a stress-free nickel powder sample. Our corrections of the pseudostrain effects in these experiments are very satisfactory.