Neutron tomography using a crystal monochromator

For several neutron tomography methods, the use of monochromatic radiation is important. In order to select a wavelength band from a white spectrum commonly used devices are velocity selectors, choppers and crystal monochromators. We show how a crystal monochromator changes the well-known L/D-ratio in CT instruments and how it determines the spatial resolution. We calculate the L/D-ratio as convolution integral and prove the results by the experimental determination of the modulation transfer function (MTF) of the used tomography system.