title: The development of a 200 kV monochromated field emission electron source.
abstract: We report the development of a monochromator for an intermediate-voltage aberration-corrected electron microscope suitable for operation in both STEM and TEM imaging modes. The monochromator consists of two Wien filters with a variable energy selecting slit located between them and is located prior to the accelerator. The second filter cancels the energy dispersion produced by the first filter and after energy selection forms a round monochromated, achromatic probe at the specimen plane. The ultimate achievable energy resolution has been measured as 36 meV at 200 kV and 26 meV at 80 kV. High-resolution Annular Dark Field STEM images recorded using a monochromated probe resolve Si-Si spacings of 135.8 pm using energy spreads of 218 meV at 200 kV and 217 meV at 80 kV respectively. In TEM mode an improvement in non-linear spatial resolution to 64 pm due to the reduction in the effects of partial temporal coherence has been demonstrated using broad beam illumination with an energy spread of 134 meV at 200 kV.
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan. Electronic address: mmukai@jeol.co.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Mukai
authors.affiliation: University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH, UK.
authors.forename: Judy S
authors.initials: JS
authors.lastname: Kim
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Omoto
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Sawada
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kimura
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ikeda
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.affiliation: JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Kaneyama
authors.affiliation: University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH, UK.
authors.forename: Neil P
authors.initials: NP
authors.lastname: Young
authors.affiliation: University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH, UK.
authors.forename: Jamie H
authors.initials: JH
authors.lastname: Warner
authors.affiliation: University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH, UK.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Nellist
authors.affiliation: University of Oxford, Department of Materials, Parks Road, Oxford, OX1 3PH, UK.
authors.forename: Angus I
authors.initials: AI
authors.lastname: Kirkland
keywords: Aberration correction; Electron energy-loss spectroscopy; Energy resolution; High-resolution imaging; Monochromator; Wien filter