title: Determination of the linear attenuation range of electron transmission through film specimens.
abstract: We have investigated the linear attenuation range of electron transmission through film specimens and its dependence on the electron energy, the acceptance half-angle of a detector or an objective aperture, and specimen properties, in the scanning transmission electron microscope (STEM) and the conventional transmission electron microscope (TEM). Electron transmission in the bright-field mode was calculated by the Monte Carlo simulation of electron scattering, and its range of the linear attenuation in film thickness was then determined by a linear least squares fit. The corresponding linear thickness range was shown to increase with the electron energy and the acceptance half-angle, although it decreased with the increase in the atomic number of specimen materials. Under the condition of a 300kV STEM or a 3MV ultra-high voltage electron microscope (ultra-HVEM), the linear attenuation range could extend to several microns for light specimen materials, and this was validated by experimental data in the ultra-HVEM. The presented results can be helpful for accurately measuring the specimen thickness or mass from electron transmission, and estimating the deviation of electron transmission from linearity when tilting a specimen in electron tomography.
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Department of Electronic Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Hai-Bo
authors.initials: HB
authors.lastname: Zhang
authors.forename: Meng
authors.initials: M
authors.lastname: Cao
authors.forename: Ryuji
authors.initials: R
authors.lastname: Nishi
authors.forename: Akio
authors.initials: A
authors.lastname: Takaoka