Masaki Taya

Development of a parallel detection and processing system using a multidetector array for wave field restoration in scanning transmission electron microscopy.

A parallel image detection and image processing system for scanning transmission electron microscopy was developed using a multidetector array consisting of a multianode photomultiplier tube arranged in an 8 x 8 square array. The system enables the taking of 64 images simultaneously from different scattered directions with a scanning time of 2.6 s. Using the 64 images, phase and amplitude contrast images of gold particles on an amorphous carbon thin film could be separately reconstructed by applying respective 8 shaped bandpass Fourier filters for each image and multiplying the phase and amplitude reconstructing factors.

Amplitude contrast of a single gadolinium atom reconstructed by a wave field restoration method

Single gadolinium atoms in fullerenes encapsulated in a single-wall carbon nanotube were observed by a wave field restoration method based on three-dimensional Fourier filtering in transmission electron microscopy. Single gadolinium atoms were clearly resolved not only in the imaginary part image but also in the real part image of the exit wave field due to an improved signal-to-noise ratio by Fourier filtering and resolution enhancement by correcting spherical aberration and twofold astigmatism. This result indicates that the present method has potential to clarify compositional details of the sample by using their image contrasts.

Development of Parallel Image Detection System Using Annular Pupils for Scanning Transmission Electron Microscope

A parallel image detection system using an annular pupil for electron optics were developed to realize an increase in the depth of focus, aberration‐free imaging and separation of amplitude and phase images under scanning transmission electron microscopy (STEM). Apertures for annular pupils able to suppress high‐energy electron scattering were developed using a focused ion beam (FIB) technique. The annular apertures were designed with outer diameter of o/ 40 μm and inner diameter of o/32 μm. A taper angle varying from 20° to 1° was applied to the slits of the annular apertures to suppress the influence of high‐energy electron scattering. Each azimuth angle image on scintillator was detected by a multi‐anode photomultiplier tube assembly through 40 optical fibers bundled in a ring shape. To focus the image appearing on the scintillator on optical fibers, an optical lens relay system attached with CCD camera was developed. The system enables the taking of 40 images simultaneously from different scattered di...