Metallothionein MT2A A-5G polymorphism as a risk factor for chronic kidney disease and diabetes : Cross-sectional and cohort studies

名古屋大学Nagoya University博士(医学)doctoral thesi

Fast-sampling fast-ion D-alpha measurement using multi-anode photomultiplier tube in large helical device

ORCID　0000-0002-5222-6082A fast-sampling fast-ion D-alpha (F-FIDA) measurement has been developed in the large helical device in order to investigate fast ion dynamics associated with helically trapped fast-ion-driven Magnetohydrodynamic (MHD) bursts. F-FIDA consists of a multi-anode photomultiplier tube (PMT) and achieves a sampling rate of 10 kHz. During the deuterium experiment campaign in 2022, F-FIDA measured the spectrum of perpendicular fast ions, using perpendicular lines of sight. We compared F-FIDA with conventional FIDA, using an electron multiplying charge coupled device, and confirmed that the time-averaged images were generally consistent between the two. The statistical properties of the temporal evolution associated with MHD bursts were analyzed using a conditional sampling technique. The results showed that the PMT signal varied in different spatial and wavelength channels. Although the signal-to-noise ratio was poor and there was room for improvement, it could provide useful information for studies on the phase-space dynamics of fast ions.journal articl

AlN/AlGaN HEMTs on AlN substrate for stable high-temperature operation

We demonstrate an AlN/AlGaN high-electron-mobility transistor (HEMT) fabricated on a free-standing AlN substrate. A metal stack, composed of Zr/Al/Mo/Au, was found to show low contact resistivity for source and drain ohmic contacts. The fabricated AlN/AlGaN HEMT exhibited a maximum drain current of 38 mA/mm with a threshold voltage of -3.4 V. Negligible drain current degradation was observed at temperatures from 300 to 573 K, emonstrating that our AlN/AlGaN approach on an AlN substrate is promising for stable high-temperature operation.othe

Evaluation of H-/D- Density Using Langmuir Probe Measurement in a Cs Seeded Negative Ion Source

ORCID　0000-0002-6271-2420An electron reduction model is reintroduced for Langmuir probe plasma density profile measurement. The model is compared with conventional laser photo-detachment measurements and can predict negative ion density in the 2-3 x 1017m−3 range using correlation factors for hydrogen and deuterium cases. The calibration and correction procedure is demonstrated for application to ion sources.journal articl

Demonstration of aneutronic p-11B reaction in a magnetic confinement device

ORCID　0000-0003-4555-1837Aneutronic fusion using commonly available fuel such as hydrogen and boron 11 (11B) is one of the most attractive potential energy sources. On the other hand, it requires 30 times higher temperature than deuterium–tritium fusion in a thermonuclear fusion reactor condition. Development of techniques to realize its potential for the experimental capability to produce proton-boron 11 (p-11B) fusion in the magnetically confined fusion device using neutral beam injection is desired. Here we report clear experimental exploration and measurements of p-11B fusion reactions supported by intense hydrogen beams and impurity powder dropper installed in the magnetic confinement plasma Large Helical Device. We measured a significant amount of fusion alpha particle emission using a custom designed alpha particle detector based on a passivated implanted planar silicon detector. Intense negative-ion-based hydrogen beam injectors created a large population of up to 160 keV energetic protons to react with the boron-injected plasma. The p-11B alpha particles having MeV energy were measured with the alpha particle detector which gave a fusion rate in a good agreement with the global p-11B alpha emission rate calculated based on classical confinement of energetic proton, using experimentally obtained plasma parameters.journal articl

A comprehensive evaluation of the thermal neutron detection efficiency by a single crystal CVD diamond detector with a LiF thermal neutron converter

ORCID　0000-0003-0920-2154Thermal neutron detection efficiency of the single crystal CVD diamond detector (SDD) equipping 1.9 μm-thick 6LiF thermal neutron converter, which induces the energetic ions through the 6Li(n,α)3H reaction, was evaluated comprehensively using a charge-integral based pulse shape discrimination (PSD) method and radiation transport calculation by PHITS. The PSD method applied in this work successfully separated the pulses induced by energetic tritons, alpha particles and other types of radiation. The detection efficiency of tritons was consistent with the radiation transport calculation, although that of alpha particles was lower than the estimation. The overall thermal neutron detection efficiency was obtained by summing detection efficiencies of tritons and alpha particles. Approximately 29% of 6Li(n,α)3H reaction occurred in an effective 1.9 μm-thick 6LiF thermal neutron converter could be detectable as the pulses of tritons (∼ 73%) and alpha particles (23%).journal articl

Response of negative ion beamlet width and axis deflection to RF field in beam extraction region

ORCID　0000-0002-5892-6047Beam-divergence characteristics of single negative ion beamlet have been experimentally investigated with a superimposition of a controlled perturbation of a radio frequency wave (RF) field in a filament-arc discharge negative ion source. Oscillations of a negative-ion beamlet width and axis responding to the RF perturbation were observed, which may be a cause of the larger beam divergence angle of the RF negative ion source for ITER. It is pointed out that the oscillation of the beamlet width depends on the perveance and on an RF frequency such that the oscillation is suppressed at perveance-matched conditions and at low RF frequencyjournal articl

Optimization of a fast deuterium diagnostic method based on visible energetic 3He spectroscopy for high electron density plasmas

0000-0003-3198-042XFast ions play a crucial role in plasma heating, and their behavior in the plasma must be accurately understood. A diagnostics method based on charge exchange emission from the n = 4 − 3 transition (λ0 = 468.6 nm) of energetic 3He produced by the deuteron–deuteron reaction has been proposed as a for fast deuterons with energies in the order of MeV. The proposed method has the following advantages: No beam emission interferes with the spectra, the direction of the measuring line of sight, and the injection angle of the diagnostic beam can be freely determined. In previous studies, due to competing bremsstrahlung, it was expected that the proposed method will not be practical in the case of high electron density operation. This paper makes the proposed method available for measurement even at high electron densities by optimizing the measurement line of sight direction and the diagnostic beam incidence angle. This allows an electron density five times larger than the range of applications shown in previous studies. This result will contribute to measure of DT alpha in ITER.journal articl

First application of data assimilation-based control to fusion plasma

ORCID　0000-0001-7597-0683Magnetic fusion plasmas, which are complex systems comprising numerous interacting elements, have large uncertainties. Therefore, future fusion reactors require prediction-based advanced control systems with an adaptive system model and control estimation robust to uncertainties in the model and observations. To address this challenge, we introduced a control approach based on data assimilation (DA), which describes the system model adaptation and control estimation based on the state probability distribution. The first implementation of a DA-based control system was achieved at the Large Helical Device to control the high temperature plasma. The experimental results indicate that the control system enhanced the predictive capability using real-time observations and adjusted the electron cyclotron heating power for a target temperature. The DA-based control system provides a flexible platform for advanced control in future fusion reactors.journal articl

Application of a Single-Crystal CVD Diamond Detector for Fast Neutron Measurement in High Dose and Mixed Radiation Fields

ORCID　0000-0002-6250-4349This article presents the method to evaluate the fast neutron energy spectrum using the single-crystal chemical vapor deposition (CVD) diamond detector to be applicable on the radiation monitoring in advanced scientific/engineering systems usually characterized with mixed and high-dose radiation field. The pulse shape discrimination (PSD) based on the shape and the width of a pulse was applied to extract events, in which fast neutron hits at the specific depth of the single-crystal diamond. Unfolding of the measured spectrum for extracted pulses could deduce the neutron energy spectrum. Experiments using monoenergetic neutron sources demonstrated the reliable capability of this method to evaluate the neutron energy spectrum quantitatively.journal articl