Optimization of measurements at neutron reflectometers

Abstract

New optimization criteria for a class of instruments, neutron reflectometers, are established by analysis of the reflectivity measurements. Luminosity of the reflectometer is defined as the neutron flux incident onto the sample surface on conditions that the measurement is made with a given momentum transfer resolution. The correct choice of the working wavelength and realization of measurements with optimum parameters of the neutron beam increase luminosity in several times. Standard schemes for the reflectivity measurements with monochromatic and white beams are considered. Optimization of the reflectivity measurements generally requires numerical calculations. Analytically, its potential is demonstrated by considering thermalized neutron beams. Such innovations as neutron-optical velocity selector, small-angle Soller collimators with traps for neutrons reflected from the channel walls and neutron fan beam time-of-flight technique are proposed to further increase the luminosity of reflectometers.