COMPARISON OF THE NUMERICAL AND ANALYTICAL CALCULATIONS OF THE RESOLUTION FUNCTION FOR A POWDER NEUTRON DIFFRACTOMETER

Abstract

The resolution of the high-intensity diffractometer, developed for the PIK reactor (Gatchina), is calculated both numerically and analytically. These two approaches give different results. All neutron trajectories calculated numerically are limited by the geometry of optical elements. Therefore, the diffraction profile has a trapezoidal shape, which can be seen well at large diffraction angles. Analytical formulas yield a Gaussian line profile. The difference in profiles leads to a difference in the resolution curves calculated numerically and analytically. This difference is especially pronounced for the diffractometers with medium and low resolution, optimized to the maximum intensity.