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The trace element content of single fluid inclusions in quartz from Tsushima granite in Japan was determined with particle-induced X-ray emission (PIXE) to investigate the chemical features of Ti in hydrothermal fluids derived from granites. Most of the fluid inclusions were polyphase and vapor-rich fluid inclusions, and both types contained Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Ge, Br, Rb, Sr, Ba, and Pb. Concentrations of Ti were of up to a few tens ppm wt Ti for polyphase inclusions and up to one hundred ppm for vapor-rich fluid inclusions. The Ti content indicated the possibility of transportation of a certain amount of Ti by granitic hydrothermal fluids.

We measured the yield of Auger electrons emitted through Coster–Kronig transitions from Rydberg states 1 s 2 p ( 3 P ) nl ( n = 7 , 8 ) and 1 s 2 2 p ( 2 P ) nl ( n = 5 , 6 , 7 ) of emergent atomic ions C q + under irradiation of 3.5-MeV/atom C+ and C 2 + ions on thin C foil targets. The Auger electron yields are suppressed for C 2 + irradiation compared with C+ irradiation and the relative yield becomes larger as n increases. Thus, amount of scattered electrons having lower relative energy in the projectile rest frame becomes larger. The results obtained in this study support the influence of projectile velocity on the cluster effect of secondary electron yields.

The first preliminary test of the 14C-accelerator mass spectrometry (AMS) system at the University of Tsukuba was successfully performed using a gas/solid hybrid ion source and an automated sample preparation system with an elemental analyzer (EA). The maximum 12C− current of ∼11 µA was achieved using the optimized CO2 flow rate to the hybrid ion source. The machine background of 14C/12C for the AMS system reached to ∼2.4 × 10−16 (∼0.02 percent modern carbon, pMC) using unprocessed mineral graphite. Moreover, the blank level of 14C/12C including the combustion process for an IAEA-C1 graphite sample was 4.6 × 10−16 (0.05 pMC), demonstrating the low blank level of the automatic sample preparation system. In contrast, the blank level of 14C/12C including the combustion process for an IAEA-C1 CO2 sample was 5.0 × 10−15 (0.49 pMC), an order of magnitude worse than that for the graphite sample. The measurement uncertainty for the gas ion source was 0.6%, 2–3 times worse than that for the solid ion source (0.2%–0.3%).

We report on the preliminary studies for two-dimensional (2D) mapping of hydrogen and other elements in materials with transmission ERDA and PIXE using a microbeam of 8 MeV 4He. The extremely enhanced forward recoil cross section of hydrogen in the non-Rutherford scattering allows 2D mapping of hydrogen in the sample. The mapping by PIXE, which provides complementary information to the mapping by ERDA, was obtained simultaneously. The present work probably leads to 3D mapping of hydrogen in bulk materials, i.e., the present spatial 2D plus depth as an additional dimension, since the energy of the outgoing hydrogen corresponds to the depth where the hydrogen is originally located.

A new submicron scanning nuclear microprobe beam line was constructed in early 2016 at the accelerator facility of the University of Tsukuba, Japan. A microbeam scanning endstage (OM-2000, Oxford Microbeams, Oxford, UK) was installed at the end of this system. The distance from the object slit to the target position is 8730 mm and the working distance is 180 mm. This ion microbeam system will be used mainly for X-ray imaging of two-dimensional distributions of light elements in structural materials using particle-induced X-ray emission (PIXE). A silicon drift detector (SDD) with a thin window of Si3N4 was installed to detect characteristic X-rays emitted from light elements such as B, C, and N, which are common additive elements in structural materials. In addition, a superconducting tunnel junction (STJ) array detector is going to be installed to perform PIXE measurements more efficiently. By combining a microbeam scanning technology with the X-ray detectors, we plan to obtain two-dimensional maps of additive light elements in structural materials. Experiments for obtaining proton microbeams are ongoing, and a 6 MeV proton beam with a diameter of between 12 and 20 μm has been obtained to date.

Three methods to detect neutrons emitted from an electrostatic accelerator were examined. These were gold foil activation, thermoluminescent dosimeters (TLDs), and CR-39. The gold-foil activation method has previously been proven effective in the measurement of neutrons emitted from cyclotron sources. In the case of electrostatic accelerators, a greater amount of fast neutrons and a smaller amount of thermal neutrons are observed compared to a cyclotron accelerator. Therefore, the error in calculating the thermal neutron flux became unacceptably large. By comparison the CR-39 detectors were apparently unable to measure thermal neutrons well, because some tracks were also generated by fast neutrons causing a signal interference. In the case of TLDs, as the material was not sensitive to fast neutrons, it was not affected by them, and hence could adequately measure the thermal neutron flux. However, it was found that in some cases its measurements could be offset by the influence of high dose rate of gamma rays.

This manuscript describes our experimental work being carried out to develop the previously published T-ERDA technique to measure H distribution in solids [Yamazaki et al., AIP Adv. 9 (2019) 105111]. From the experiments for the samples with H markers, we have identified the factors that degrade the depth resolution for analysis of H distribution, depending on the acceptance conditions of the detector., Comment: 13 pages, 5 figures

We have measured microscopic 3-dimensional distribution of plasma-charged hydrogen in polycrystalline Al. The measurements have been carried out nondestructively by using elastic recoil detection analysis under transmission geometry of a collimated 8 MeV 4He2+ beam. The recoil cross section as large as 2 × 103 mb/sr due to the nuclear elastic collision allowed observation of the spatial distribution of hydrogen in the Al sample of 80 μm thickness. The distribution maps of hydrogen clearly visualize hydrogen bubbles of 10–20 μm diameter in the surface layer of about 12 μm thickness. The critical concentration of hydrogen minimally needed for growth of the hydrogen bubble of ten-μm size has been determined to be 1.6 × 1020 cm−3.

We report on a new route for synthesizing metastable anatase tantalum oxynitride (TaON) in thin film form on lattice-matched (LaAlO3)0.3-(SrAl0.5Ta0.5O3)0.7 (LSAT) single crystals by using nitrogen plasma assisted pulsed laser deposition. Epitaxial stress from the substrate stabilized the anatase structure without the need for doping an impurity, such as Sc or Mg, which is required in conventional bulk synthesis by ammonolysis. X-ray diffraction measurements and cross-sectional transmission electron microscope (TEM) observations demonstrated the growth of phase-pure anatase TaON thin films with the epitaxial relationships (001)TaON ∥ (001)LSAT and [100]TaON ∥ [100]LSAT. A high growth temperature (≥750 °C) and a balanced supply of oxygen and nitrogen are crucial for obtaining high-quality anatase TaON thin films. The films grown at 800 °C exhibited good n-type conduction with a resistivity of ∼1 × 10–2 Ω cm. The source of the carrier electrons was likely anion vacancies. The Hall mobility of anatase TaON (...

We apply the capillary beam-focusing method for the C 60 fullerene projectiles in the velocity range between 0.14 and 0.2 a.u. We study the C 60 transmission properties through two different types of capillaries: (1) borosilicate glass microcapillary with an outlet diameter of 5.5 μm, and (2) Al 2 O 3 multi-capillary foil with a pore size of about 70 nm and a high aspect ratio of about 750. We measured the transmitted particle composition by using the electrostatic deflection method combined with the microchannel plate imaging technique. For the experiments with the single microcapillary, the main transmission component is found to be primary C 60 beams that are focused in the area equal to the capillary outlet diameter. Minor components are charge-exchanged C 60 ions and charged or neutral fragments (fullerene-like C 60-2 m and small C n particles), and their fractions decrease with decreasing the projectile velocity. It is concluded that the C 60 transmission fraction is considerably high for both types of the capillaries in the present velocity range.

We study the transmission properties of fast cluster ions (Cn+ (n = 2–4) with velocities ranging from 0.89 to 1.79 a.u.) through a single tapered capillary with an outlet diameter of 13.7 μm. We investigate the projectile-velocity dependence of the transmission fraction from the measurements of transmitted particle energy spectra. It is found that the non-fragmentation fraction of C2+ projectiles increases with decreasing velocity, indicating that fragmentation occurs mainly via close collisions with the surfaces of the capillary wall. For Cn+ (n = 2–4) ions with the same incident velocity, the cluster-size dependence of the non-fragmentation fraction shows even–odd alternation, implying that the fraction includes contributions from stable clusters surviving the grazing scattering process at the capillary surface. We also find that the angular distribution of transmitted particles is narrower for cluster projectiles compared with atomic projectiles.

Reduction in polarization dependent loss of a planar lightwave circuit was achieved by asymmetric birefringence formed by ion implantation, in which oxygen ions were implanted along a diagonal of a cross-section of the planar lightwave circuit. The induced birefringence has a slow axis along the line perpendicular to the diagonal. In the present research, a decrease in polarization dependent loss of up to 3.7 dB was obtained, indicating that the method is effective for reducing polarization dependent loss.

Analytical errors in single fluid inclusion analyses by PIXE were investigated to evaluate the accuracy and detection limits of this type of analysis. Analytical errors due to the ellipsoidal approximation of the inclusion shape and the presence of a precipitated halite crystal in the inclusion were much smaller than the total analytical error. The major source of error in the quantification was the uncertainty in the determination of the inclusion depth, which can be minimized by using measurements of the Cl Kβ/Kα intensity ratio. The total analytical error was ±17% relative for most elements and ±40% relative for Cl. Detection limits of 15–40 ppm for elements with mass numbers 25–38 were achieved in analyses of ellipsoidal fluid inclusions (size, 50 μm × 30 μm × 30 μm; depth, 10 μm; bubble size, 15 μm; and NaCl solution, 10 wt%) in quartz, at an integrated charge of 1.0 μC and beam size of 50 μm × 50 μm. The trace-element compositions of single fluid inclusions in quartz crystals from a miarolitic cavity or from quartz veins within a granite body were also determined to investigate the chemical compositions of granite-derived fluids and compositional changes in the fluids during fluid movement in a granite body.

The thermal neutron fluence that poured into the shielding concrete of proton accelerator facilities was estimated from the in situ production of 36Cl. The thermal neutron fluences at concrete surfaces during 10–30 years of operation were in the range of 1012–1014 n/cm2. The maxima in thermal neutron fluences were observed at ≈5–15 cm in the depths analyzed for 36Cl/35Cl by AMS. These characteristics imply that thermalization of neutrons occurred inside the concrete. Compared to the several tens of MeV cyclotrons, secondary neutrons penetrate deeper into the concrete at the high-energy accelerators possessing acceleration energies of 400 MeV and 12 GeV. The attenuation length of neutrons reflects the energy spectra of secondary neutrons emitted by the nuclear reaction at the beam-loss points. Increasing the energy of secondary neutrons shifts the maximum in the thermal neutron fluences to deeper positions. The data obtained in this study will be useful for the radioactive waste management at accelerator facilities.

Compressively strained SrTaO2N thin films were epitaxially grown on SrTiO3 substrates using nitrogen plasma-assisted pulsed laser deposition. Piezoresponse force microscopy measurements revealed small domains (101–102 nm) that exhibited classical ferroelectricity, a behaviour not previously observed in perovskite oxynitrides. The surrounding matrix region exhibited relaxor ferroelectric-like behaviour, with remanent polarisation invoked by domain poling. First-principles calculations suggested that the small domains and the surrounding matrix had trans-type and a cis-type anion arrangements, respectively. These experiments demonstrate the promise of tailoring the functionality of perovskite oxynitrides by modifying the anion arrangements by using epitaxial strain.

We have developed a laser coupling with an electron cyclotron resonance (ECR) ion source for trace element analysis of mineral samples at University of Tsukuba. A compact Q-switched Nd:YAG laser at 1064 nm wavelength with a pulse width of 8 ns and a maximum energy of 50 mJ is employed to ablate the sample materials as a means of introducing samples into the ECR plasma. Preliminary experiments were performed to focus the laser beam on a pure metallic target (Cu). The mean kinetic energy of the laser produced Cu ions is measured to 470 eV for the laser energy of 50 mJ by a simple time-of-flight method. Design for a laser coupling with an ECR ion source as a new application of mass spectrometry are reported.