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In TIARA facility of Japan Atomic Energy Agency (JAEA) Takasaki, we have produced three-dimensional micro/nano-structures with high aspect ratio using cross linking process based on negative resist such as SU-8 by a technique of mask less ion beam lithography. By bombarding high energy heavy ions such as 450 MeV Xe 23+ to SU-8, on the other hand, it appeared that a nanowire could be produced just with a single ion hitting. Then we tried to produce nanowires, of which both ends were fixed in the three-dimensional structure. This paper shows a preliminary experiment for this purpose using a combination of 15 MeV Ni 4+ ion microbeam patterning and the 450 MeV 129 Xe 23+ hitting on SU-8.

An ion-beam-lithography technique has been progressed in the microbeam systems at Japan Atomic Energy Agency (JAEA) Takasaki. In order to obtain a high-precision measure for microbeam size estimation with a high precision, we applied this technique combined with the electroplating process to make a Ni relief pattern as a resolution standard used in secondary electron imaging. As a result, the smallest beam size could be recorded. The scattering of ions in the materials influenced the spatial resolution and this is also discussed.

A high energy focused ion beam with sub-μm spatial resolution was used to produce isolated nano-wires which were planted on the substrate. Each charged particle penetrating into a polymer thin film gave a corresponding nano-wire, whose length reflected precisely the thickness of the target film. Based on the tight connection of one end of each nano-wire on the substrate, the focused ion beam achieved position selective nano-wire or nano-wire bundle formation on the substrate. The ion beam, with the small spot size (Φ) < 500 nm, was electrostatically controlled to irradiate the polymer thin films, leading to the patterns of nano-wire bundles with high spatial resolution

Structural and optical properties of silica glass induced by ion microbeam irradiation were studied using micro- photoluminescence (μ-PL) spectroscopy and atomic force microscopy (AFM). Ion microbeam irradiation was performed using microbeam lines of 3-MV single-ended or tandem accelerators with various ion species including H+, He+, B3+, C4+, N4+, O4+, and Si5+ at energies of 1.7 to 18 MeV. The beam was focused to about 1 μm and was scanned over the surface of high-purity silica glass with fluences of 1013 to 1018 ions/cm2. The μ-PL spectrum in microbeam-irradiated silica shows two peaks at 540 and 650 nm. The mapping of the two PL bands reveals the distribution of defects induced along the track of ions. The compaction was observed in the form of groove at the surface of silica glass by AFM. The depth of the surface groove increases with increasing ion fluence and saturates at about several hundreds to 900 nm, depending on irradiated ion species. The mechanisms of structural and optical modifications of silica glass are can be understood in terms of energy loss due to electronic stopping and nuclear stopping powers. Refractive index changes with an order of 10– 4 to 10− 2 were estimated by a Lorentz–Lorenz relationship from the compaction. Technological implications of these results are also to be discussed.

High-purity silica glass was irradiated by a focused 15-MeV O 4+ microbeam with diameter of 1 μm up to a fluence of 1.0 × 10 14 ions/cm 2 . Spatial distribution of irradiation effects by the O 4+ microbeam on silica glass was investigated by optical microscopy, microphotoluminescence (PL)/Raman spectroscopy and atomic force microscopy (AFM). Distribution of refractive index change and defect formation was visualized by optical microscopy and PL mapping, indicating the structural changes of silica glass along the ion track up to the depth of 10 μm. In addition, we observed deformed side surface with a groove by AFM along the track suggesting the internal compaction in silica glass. This is accompanied by increased threefold rings of SiO 2 network detected by Raman scattering. We also discuss technological implications of these results on the applications of microbeam irradiation effects to the fabrication of microoptical elements.

Heavy element-sorbing montmorillonite and apatite were analyzed by micro-PIXE to examine its applicability to quantitative analysis of the heavy elements sorbed on these minerals. It was found that the sorbed heavy elements can be evaluated quantitatively using the linear correlation between the following two factors: (a) the concentration of the sorbed element in the mineral and (b) the ratio of the net peak area of characteristic X-ray from the sorbed element and to that from the matrix cation of the mineral. Mineralogical features of the tested minerals including heterogeneity of elemental distribution in the depth direction of the mineral hardly affected the results.

Distributions of structural and refractive index changes of silica irradiated by H + microbeam were studied by optical and atomic force microscopes (AFM). The AFM measurements on the microbeam irradiated area show the formation of a groove on the surface. In addition, a cross sectional observation on the surface parallel to the incident plane reveals surface deformation along the ion tracks, which is deepest at the projected range of ions. Taking into account the possible structural changes of silica induced by energy deposition calculated by TRIM, the measured topological changes at the front and side surfaces result from internal compaction of silica glass. Refractive index changes were estimated from the Lorentz–Lorenz relationship using the distribution of the internal compaction estimated by the AFM measurements.

To study the interactions between the induction of radiation-induced apoptosis and trace elements kinetics, human leukemia cells were irradiated in vitro by 60 Co γ rays, after which the cells were evaluated for the detection of apoptosis and trace element (Fe, Ca, Zn) imaging was carried out. The frequency of apoptosis, i.e. the number of apoptotic bodies per 100 nuclei, was obtained by microscopic assay using TUNEL staining at 400× magnification. The trace element distribution in the cell was determined by micro-PIXE using 2 MeV proton beams. In the early phase of apoptosis, the maximum level of Fe accumulation was observed in the cell stroma. In the mid to end phase, Fe accumulation was diminished, and instead, Ca accumulation increased and Zn decreased in the nucleus. There appear to be two steps for the development of apoptosis: (1) the signaling from cell stroma to nucleus by Fe or an Fe-containing enzyme; and (2) the degeneration of the nucleus by Ca-dependent enzyme, and release of Zn from digested nucleus. Those strong accumulations may be new markers for apoptosis.

We evaluated structural changes in silica glass induced by ion microbeam using microscopic photoluminescence (PL) and Raman scattering measurements. Microbeams (1.7 MeV H+) were scanned over the sharp right-edges of the silica substrates with a fluence of 1×1017 cm−2, then two PL bands of silica at 540 and 650 nm were observed at the irradiated region. The PL bands show different lateral and depth distributions. The distribution of the 540 nm PL is in good agreement with that of the refractive index changed region. The lateral distribution of the 650 nm band is broader by 1.5 times than those of the 540 nm PL and the refractive index changed region. The microscopic Raman scattering measurements show an increased intensity of 606 cm−1 peak associated with compaction at the microbeam irradiated regions.

We developed a novel technique to obtain 3D-imaging of elemental distribution based on multi-angle RBS measurement and micro-beam scanning. Since cross-sections of RBS are too small to obtain 3D-imaging, it is necessary to measure scattered particles with large solid angle detectors. Hence, the RBS profiles from each scattering angle are superposed and a true depth profile cannot be obtained. Recently, a large solid angle X-ray detector array consisting of 45 detector elements was installed at the TIARA facility of Japan Energy Research Institute. Each detector element measures X-rays as well as scattered particles. For this utilization, we introduced a technique to superpose RBS profiles and applied it to the surface analysis of an ant’s head.

Microhabitats of bacteria (biomat) and lower plants, such as lichen and mosses, are known to accumulate hazardous elements. Since the concentration of hazardous elements in the environment is quite low, we have applied the in-air μ-PIXE (particle induced X-ray emission) system developed in the TIARA facility of JAERI, which has low concentration detection limit of ppm, to measure As, one of the hazardous elements, distributions in biomat, lichen and mosses observed around an abandoned As mine site in Gunma, Japan to elucidate the applicability of these biomat and lower plants as bio-indicators of As. Spatial distributions of As, Fe, Si and S in all biomat, lichen and moss collected within 3 m from the mine entrance indicate that As is localized, and is associated with silicate and Fe-containing compounds. In addition, the intensity ratio of peak area for As to Fe in μ-PIXE spectrum of the moss collected from the concrete wall at 3 m downstream of the mine water discharge position is different from those of the lower plants on the rock near the closed entrance, but is the same as that of biomat formed at the mine water discharge position. This indicates that As trapped by the moss on the concrete wall probably has the same origin as the biomat. It is concluded that application of μ-PIXE analysis to the measurement of As in the lower plants and biomat gives not only the distribution of the hazardous element of As, but also the information of the origin.

Radiation effects induced by ion microbeam were studied by a confocal microspectroscopy and an atomic force microscopy (AFM). We investigate two significant radiation effects, defect generation and compaction, which were ascribed to electronic (Eelec) and nuclear stopping powers (Enucl), respectively. Photoluminescence mapping of nonbridging oxygen hole centers at 650 nm reveals the defect formation along the tracks of ions. The surface deformation measured by AFM depends on the width of irradiated by microbeam. Confinement effects from the interface of irradiated and nonirradiated regions are taken into account for the understanding of the correlation between the surface deformations and internal compactions.

Alkylene groups incorporated porous silica films were prepared by using hydrolysis and condensation of BIS (Triethoxysilyl) Ethelene (BTE). BTE and H 2 O containing HCl as a catalyst were mixed with organic solvent, 2-Methylpentane-2,4-diol (MPD). FT-IR peaks due to MPD were not observed but Si–C 2 H 4 –Si related peaks were still observed in the film even after 450°C vacuum annealing. Electric characteristics were evaluated with an MOS structure. K value does not depend on the annealing temperature below 400°C; however, it was reduced down to 1.9 at 450°C.

Single Event Effects (SEEs) triggered by energetic heavy ions traversing a sensitive parts of electric devices have been studied using high-energy heavy ion microbeams connected with Transient Ion Beam Induced Current (TIBIC) measuring system at the Japan Atomic Energy Agency (JAEA) Takasaki Ion Accelerators for Advanced Radiation Applications (TIARA) facility. In the TIBIC system, SEE for semiconductor device, that is fast charge collection, has been observed in timescales of the order of picoseconds. In this paper, we show successful demonstration of the performance of the system, in which clear images of TIBIC map have been observed for Si pin photodiodes irradiated by 260 MeV 20 Ne 7+ and also by 520 MeV 40 Ar 14+ microbeams.

Aiming to develop a compact and inexpensive in situ cleaning device, an experiment on the removal of hydrocarbon by oxygen and hydrogen plasmas was carried out. The plasmas were produced using a 60 MHz RF-discharge. The oxygen plasma had an electron temperature Te=5 eV and an ion density was 2×10 10 cm -3 with a pressure of 2.3 m Torr and an RF power of 130 W. Observations showed a decrease in the hydrocarbon pressure by about two orders of magnitude after irradiation by the oxygen plasma for about 1 h, though much of the decrease occurred in the first few minutes.

A new beam line to allow parasitic experiments in two separate experimental halls has been installed. The total length of the beam line is about 80 m. Two achromatic 90° deflecting systems have been incorporated. For the beam delivered to the second experiment, the beam diameter was 2 mm and the emittance was 1 mm mrad. The duty factor was reduced to an average of 50% from 80%. This decrease was satisfactorily recovered using a deflector system synchronized with the beam pulse. The tagged photon beam, and experimental conditions were significantly improved when the transported beam was used. Successful parasitic experiments involving electron scattering and tagged photon experiments have now been demonstrated.

An investigation has been made into the dependence of magnetoresistance on both the composition and annealing temperature for Ni-Fe-Co ternary alloy films. The anisotropic magnetoresistivity ratio Δϱ/ϱ 0 exhibits a maximum in the composition range of 76–86 wt% for Ni, 0–7 wt% for Fe and 10–20 wt% for Co. The anisotropic magnetoresistivity Δϱ exhibits a broad maximum in the neighborhood of the n B = 0.9 μ B , suggesting that the spin-orbit coupling is the most likely mechanism to explain the magnetoresistance effect. The resistivity decreased about 15% for annealing temperatures above 300°C, while the anisotropic magnetoresistivity remained unchanged. Annealing at temperatures above 300°C increases the dispersion of the induced magnetic anisotropy due to the growth of crystallites. Consequently, the hysteresis in the ϱ vs. H curve becomes enhanced. The dependence of resistivity on the size of the crystallites is discussed based on the grain-boundary scattering model proposed by Mayadas and Shatzkes.