title: Accurate measurement of relative tilt and azimuth angles in electron tomography: a comparison of fiducial marker method with electron diffraction.
abstract: Electron tomography is a method whereby a three-dimensional reconstruction of a nanoscale object is obtained from a series of projected images measured in a transmission electron microscope. We developed an electron-diffraction method to measure the tilt and azimuth angles, with Kikuchi lines used to align a series of diffraction patterns obtained with each image of the tilt series. Since it is based on electron diffraction, the method is not affected by sample drift and is not sensitive to sample thickness, whereas tilt angle measurement and alignment using fiducial-marker methods are affected by both sample drift and thickness. The accuracy of the diffraction method benefits reconstructions with a large number of voxels, where both high spatial resolution and a large field of view are desired. The diffraction method allows both the tilt and azimuth angle to be measured, while fiducial marker methods typically treat the tilt and azimuth angle as an unknown parameter. The diffraction method can be also used to estimate the accuracy of the fiducial marker method, and the sample-stage accuracy. A nano-dot fiducial marker measurement differs from a diffraction measurement by no more than ±1°.
authors.affiliation: National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Hayashida
authors.affiliation: National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton T6G 2M9, Canada.
authors.forename: Marek
authors.initials: M
authors.lastname: Malac
authors.affiliation: National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton T6G 2M9, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Bergen
authors.affiliation: National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton T6G 2M9, Canada.
authors.forename: Ray F
authors.initials: RF
authors.lastname: Egerton
authors.affiliation: National Institute for Nanotechnology, 11421 Saskatchewan Drive, Edmonton T6G 2M9, Canada.
authors.forename: Peng
authors.initials: P
authors.lastname: Li