Affiliations: Institut Laue-Langevin, F-38042 Grenoble, Cedex 09, France | Los Alamos National Laboratory, Los Alamos, NM 87545, USA | Department of Materials and Nuclear Engineering, University of Maryland, College Park, MD 20742-2115, USA
Note: [] Corresponding author.
Abstract: Disk chopper cascades are used to produce pulsed beams of monochromatized neutrons. The optimization problems involved in the design of a new cascade are complex due to the interrelation of neutron guide and chopper system. We will present here a novel approach towards analyzing the part of the optimization concerned with the contamination of the spectrum by parasitic neutrons. To this end the cascade is decomposed into a suite of band pass filters. By folding the Boolean transmission function of the single filters we obtain an analytic solution for the contamination problem. In contrast to Monte-Carlo simulations our approach offers a better insight into the parameters governing the transmission of side bands.
Keywords: Time-of-fight, Choppers, Velocity selectors, Band pass filters, Neutron instrumentations
