Sakumi Moriguchi

Utility test of imaging plate as a high-resolution image-recording material for radiation-sensitive specimens

Abstract The utility of an imaging plate in high-resolution electron microscopy for radiation-sensitive specimens was tested in terms of the quality factor in a range of accelerating voltages between 200 and 1000 kV. The sensitivity of an imaging plate decreases with increasing accelerating voltage in a manner similar to the case of electron microscopic films and is still higher at high accelerating voltages, although the resolution is much lower. As a whole, the quality factor F = S/δ2, where S is the sensitivity and δ the resolution of the imaging plate, takes its maximum value at an irradiated electron dose of 10-1 C/cm2 and is lower than that of the films.

A comparative study of the modulation transfer function of an imaging plate

Abstract An important factor to specify properties of an imaging plate (IP) is the modulation transfer function (MTF) which defines the resolving power of this recording material. The MTF of an IP was measured by comparing the shadow profile of a gold wire directly fixed on an IP with an ideal well-shaped profile, while, additionally, its dependence on the accelerating voltage and also on the irradiated electron dose was studied. The MTF was found not to depend on the accelerating voltage, but to be in close correlation with the irradiated dose. The practical resolution becomes worse with decreasing dosage. The resolving power determined from the MTF value of about 0.15 corresponded to the line resolution determined by the observation of lattice fringes.

Formation of ultrafine platinum particles in an aqueous solution with a surfactant

Abstract The formation process of ultrafine metal particles in water was examined with a cryogenic transmission electron microscope by using a rapid-freezing specimen-preparation technique. The particles were formed by hydrogen reduction in an aqueous solution of chloroplatinic acid with or without a surfactant. The ultrafine platinum particle was obtained with the surfactant, and they were concluded as formed not in a micelle as a nucleation site, but in arbitrary places in solution. During the formation process, the particles are coated and stabilized by surfactant molecules so as to not aggregate, when using the surfactant.

Pseudomorphic Structure of Vacuum-Deposited Fluorinated Vanadylphthalocyanine (VOPcFx) and its Optical Absorption Spectra

Abstract Pseudomorphic structure of fluorinated vanadylphthalocyanine was formed on alkali halides and was analyzed by electron diffraction method using imaging plate and high resolution molecular imaging. The body-centered-tetragonal structure analyzed exhibits peak shifts in optical transmittance depending on the sort of alkali halides used as substrates.

A new 1000 kV HREM for organic crystal study

Abstract On the basis of the success in high-resolution observation at the atomic level with the previous 500 kV HREM, a new 1000 kV EM was constructed and installed at Kyoto University. The split-tank system was adopted for the HV supply to increase the potential stability. The objective lens system of high excitation was computer-designed to reduce the spherical aberration. A new image-recording system with highly sensitive imaging plate was attached in view of the quantitative measurements for the digital image processing and for the ED structure analysis. Some high-resolution images were obtained to be inspected by laser-optical diffraction which indicated the achievement of resolution better than 0.13 nm.

Application of an imaging plate to electron crystallography at atomic resolution

An imaging plate was used to quantitatively measure the electron diffraction intensities of graphite and polyethylene (PE) crystals. After the signs of the structure factors were assigned by using a direct phasing procedure, potential maps were made in order to determine atomic positions. Peaks corresponding to the carbon atoms in graphite were seen at (0,0), (13,23) and 23,13) in the map of the c-axis projection. For PE, hydrogen atoms were resolved in addition to carbon atoms due to the higher scattering powers of hydrogen for electron beam than for X-ray. The setting angle of the molecular chain in the c-axis projection of the unit cell was determined to be 46.0°, which is consistent with the results of X-ray experiments. R-factors were found to be 0.228 and 0.197 for graphite and PE, respectively. It is shown that the high sensitivity, the wide dynamic range, the good linear response and the digital output data of the imaging plate are useful for structure analysis using electron diffraction.

Vacuum-deposited Thin Films of (μ-Oxo)bis[(phthalocyaninato) aluminium(III)]((AIPc)2O)

Abstract Thin films of μ-oxo dimer, (AlPc)2O, deposited on KCl and NaCl in vacuum show epitaxy. The high-resolution image, electron and X-ray diffraction patterns indicate that the structure of (AlPc)2O thin film is the triclinic form reported by Wynne. The crystal grow making their molecular planes parallel to the substrate surface. The crystal orientations on KCl and NaCl are same and the angle between the α-axis of the film and the (100) of KCl is about 26°.