Elsevier, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, (741), p. 26-32, 2014
DOI: 10.1016/j.nima.2013.12.036
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We discuss the implications of a long pulse neutron source for the chopper system of direct geometry time-of-flight spectrometers. While the same conditions apply for the layout of the resolution defining choppers as on reactor based instruments, we emphasize the multi-chromatic nature of the instruments. The chopper system must not only provide a unique assignment of the wavelength to each pulse, but also provide adopted time frames matching the respective energy of the pulse. We propose a chopper system consisting of disc choppers, heavy T0 choppers and a newly developed Fan chopper to account for the various challenges due to the long pulse nature.