Time dependent fast neutron background: understanding the cause and identifying a solution for the PELICAN cold neutron spectrometer
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Date
2018-12
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Elsevier
Abstract
During the commissioning phase of the cold neutron chopper spectrometer PELICAN at ANSTO, a strong pulsed fast neutron background in-phase with the slave chopper has been observed. Through a series of diagnostic measurements the major components of this background have been identified. The fast neutrons are generated by photoneutron production in the Be filter as a secondary process to γ production during neutron absorption. The Be filter has been modified to minimise the fast neutron generation. Ultimately, the time dependent background has been completely removed by phasing two Fermi choppers, instead of using a Be filter to remove high order reflections from the monchromator. © 2017 Elsevier B.V.
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Keywords
Neutrons, Neutron spectrometers, Time Dependence, Cold neutrons, Fast neutrons, Absorption, Measuring instruments, ANSTO, Fast neutrons, Spectrometers, Neutron choppers, Monochromators
Citation
Elcombe, M. M., Mole, R. A., & Yu, D. H. (2018). Time dependent fast neutron background: understanding the cause and identifying a solution for the PELICAN cold neutron spectrometer. Paper presented to the 11th International Conference on Neutron Scattering (ICNS 2017), 9-13 July, Daejeon, Korea. In Physica B: Condensed Matter, 551, 347-350. doi:10.1016/j.physb.2017.11.062