If stress-free sample is measured near surface by residual stress neutron diffractometer

shift of diffraction peak position(pseudo shift) will be introduced due to intrinsic properties of diffractometer.In order to improve accuracy of stress measurement

suitable methods to reduce the pseudo shift are necessary.In this paper

methods for reducing the pseudo shift are systematically investigated by ray-tracing program SIMRES.The results indicate that wavelength and peak clipping effects can be depressed by primary and secondary radial collimators

respectively.In this way the pseudo shift is effectively reduced.