Correction of optical aberrations in elliptic neutron guides

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dc.contributor.authorBentley, PMen_AU
dc.contributor.authorKennedy, SJen_AU
dc.contributor.authorAndersen, KHen_AU
dc.contributor.authorRodriguez, DMen_AU
dc.contributor.authorMildner, DFRen_AU
dc.date.accessioned2014-04-23T03:01:29Zen_AU
dc.date.available2014-04-23T03:01:29Zen_AU
dc.date.issued2012-11-21en_AU
dc.date.statistics2014-04-23en_AU
dc.description.abstractModern, nonlinear ballistic neutron guides are an attractive concept in neutron beam delivery and instrumentation because they offer increased performance over straight or linearly tapered guides. However, like other ballistic geometries they have the potential to create significantly non-trivial instrumental resolution functions. We address the source of the most prominent optical aberration, namely coma, and we show that for extended sources the off-axis rays have a different focal length from on-axis rays, leading to multiple reflections in the guide system. We illustrate how the interplay between coma, sources of finite size, and mirrors with non-perfect reflectivity can therefore conspire to produce uneven distributions in the neutron beam divergence, a source of complicated resolution functions. To solve these problems, we propose a hybrid elliptic-parabolic guide geometry. Using this new kind of neutron guide shape, it is possible to condition the neutron beam and remove almost all of the aberrations, whilst providing the same performance in beam current as a standard elliptic neutron guide. We highlight the positive implications for neutron scattering instruments that this new shape can bring. © 2012, Elsevier Ltd.en_AU
dc.identifier.citationBentley, P. M., Kennedy, S. J., Andersen, K. H., Rodriguez, D. M., & Mildner, D. F. R. (2012). Correction of optical aberrations in elliptic neutron guides. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 693, 268-275. doi:10.1016/j.nima.2012.07.002en_AU
dc.identifier.govdoc4762en_AU
dc.identifier.issn0168-9002en_AU
dc.identifier.journaltitleNuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipmenten_AU
dc.identifier.pagination268-275en_AU
dc.identifier.urihttp://dx.doi.org/10.1016/j.nima.2012.07.002en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/5473en_AU
dc.identifier.volume693en_AU
dc.language.isoenen_AU
dc.publisherElsevier Science BVen_AU
dc.subjectNeutron guidesen_AU
dc.subjectNeutron beamsen_AU
dc.subjectSpectrometersen_AU
dc.subjectElliptical configurationen_AU
dc.subjectShapeen_AU
dc.subjectNeutronsen_AU
dc.titleCorrection of optical aberrations in elliptic neutron guidesen_AU
dc.typeJournal Articleen_AU
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