National Institutes for Quantum and Radiological Science and Technology
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Hybrid Quantum Sensing in 4H-SiC Enabled by the Integration of Vanadium and Silicon Vacancy for Simultaneous Temperature and Magnetic Field Detection
No full textIsolated vanadium (V) ions and silicon vacancies (VSi−) in 4H-SiC are promising candidates for quantum light sources and sensors owing to their stable near-infrared photon emission and optically addressable spin states. In this paper, we present a hybrid quantum sensing platform based on 4H-SiC incorporating both V and VSi− centers. We investigate the temperature dependence of photo- and electro-luminescence from V centers in 4H-SiC, and demonstrate an O-band light-emitting diode (LED) based on a V-doped 4H-SiC PiN structure, operating stably up to 523 K. Furthermore, we successfully fabricate 4H-SiC containing V and VSi− centers by employing high-energy electron irradiation. These centers are spectrally distinct, allowing ratiometric thermometry based on the emission intensity ratio between V and VSi− centers. This sensing scheme achieves high relative sensitivity (1.74 % K−1), high resolution (0.143 K Hz−1/2) and a broad operational range (79 K to 623 K), highlighting its practical applicability. Additionally, we demonstrate simultaneous detection of magnetic field and temperature by combining optically detected magnetic resonance of VSi− with the ratiometric thermometry. This simple and scalable sensing scheme highlights the potential of SiC as a multifunctional quantum material, enabling the integration of multiple optically addressable spin defects for advanced quantum technologies.journal articl
Photoelectrical detection and characterization of divacancy and PL5-PL7 spins in silicon carbide
No full textPhotoelectrical detection of magnetic resonance (PDMR) offers a scalable alternative to optical readout of spin defects in semiconductors and is particularly promising for near-infrared (NIR) emitters, where photodetection is often challenging. Here, we demonstrate room-temperature coherent PDMR of PL3 (divacancy), PL5, PL6, and PL7 spins. PL7 and PL5 exhibit notably stronger PDMR than PL6 as opposed to optical detection, indicating higher ionization efficiency and suitability for electrical readout. Rabi oscillation and two-frequency spectroscopy reveal a previously undiscovered secondary resonance of PL7. We determine the zero-field splitting parameters of PL7 and assign the recently reported PL3a defect to PL7. The demonstrated PDMR of these NIR defects constitutes a key advancement toward quantum electronic devices. Also, the clarified spin parameters and ionization characteristics provide a solid foundation for advancing quantum technologies utilizing these defects regardless of the detection schemes.journal articl
量子ドット温度センシングを用いた神経⾎管ユニットによる局所温度調整機構の解明
No full text神経⾎管ユニットによる局所温度調整機構について発表する。Neurovascular Unit 研究会 2026conference presentatio
ITER用計測機器の健全性評価のための中性子照射試験
No full text量研ITERプロジェクト部では、マイクロフィッションチェンバー(MFC)、ポロイダル偏光計(PoPola)、周辺トムソン散乱計測(ETS)、ダイバータ不純物モニター(DIM)、ダイバータ赤外線サーモグラフィー(IRTh)の５つのITER用計測装置の開発を進めている。開発においては、各計測機器の耐放射線性（ガンマ線および中性子線）の検証を行うことが重要な課題となっている。本研究の目的は、研究用原子炉から発生する高い中性子フラックスを利用することにより、ITERの20年間に渡る運転期間中にITER真空容器外に設置する計測機器が受けるフルエンスと同程度の中性子線を照射した後でも計測機器の性能維持などの機器の健全性を維持できるかを明らかにすることである。本研究では、2019年度より実験課題として、上記計測装置のうち中性子の影響が大きな部品等に中性子を照射し、その信頼性の評価を行っている。本報告では、研究の進展等に関して報告する。第60回 京都大学複合原子力科学研究所学術講演会conference poste
Is soft X-ray irradiation of a high-LET like nature? -dependence of X-ray energy in cross-linking yield of polydimethylsiloxane and halogenated polystyrenes
No full textIn a previous study, we investigated the dose response of alanine dosimeters irradiated with 2.0–7.0 keV monochromatic X-rays and found that the soft X-ray irradiation should be a high-LET like nature (Radiat. Phys. Chem. 214, 111304). The lower energy of Auger- and photo-electrons ejected from the irradiated materials will cause high LET irradiation. This suggests that soft X-ray irradiation can induce the effective cross-linking of polymer. In the present study, we examined the cross-linking behavior of polydimethylsiloxane and halogenated polystyrenes under 2.5–5.0 keV monochromatic X-ray irradiations. The cross-linking yield increased with the dose and saturated at significantly lower dose than those achieved with high-energy photons or electrons. The result is the reverse trend of alanine radical yield observed in the previous study. The cross-linking yields of halogenated polystyrenes highlight the influence of Auger- and photoelectron energies modulated by both halogen substitution and the energy of X-rays on the cross-linking process. Finally, cross-linking efficiency can be controlled by the type of element present in the polymer and X-ray energy.journal articl
GATE 10 Monte Carlo particle transport simulation: II. Architecture and innovations
No full textWe present GATE version 10, a major evolution of the open-source Monte Carlo simulationapplication for medical physics, built on Geant4. This release marks a transformative evolution,featuring a modern Python-based user interface, enhanced multithreading and multiprocessingcapabilities, the ability to be embedded as a library within other software, and a streamlined frameworkfor collaborative development. In this Part 1 paper, we outline GATE’s position among otherMonte Carlo codes, the core principles driving this evolution, and the robust development cycleemployed. We also detail the new features and improvements. Part 2 will focus on the architecturalinnovations and technical challenges. By combining an open, collaborative framework withcutting-edge features, such a Monte Carlo platform supports a wide range of academic and industrialresearch, solidifying its role as a critical tool for innovation in medical physics.journal articl
Terahertz vibrational condensation in out-of-equilibrium nanoscale reverse micelles
No full textIn situ terahertz absorption spectroscopy has been conducted under microwave energy input at 2.45 GHz for nanoscale reverse micelles. We have observed a spectral transition at ~0.32 THz for interfacial water in the reverse micelle. That is, the spectral amplitude is remarkably enhanced, accompanied by spectral narrowing and a shift to lower frequencies above a certain microwave intensity, compared to the spectrum in thermal equilibrium. This spectral narrowing reaches the experimental resolution of ~5 GHz, indicating the coherent vibration lasting for at least ~200 ps. These features agree with those derived from the terahertz vibrational condensation proposed by Fröhlich. Furthermore, it is considered that this condensation occurs in heat flow resulting from an inhomogeneous temperature distribution in the sample solution induced by microwave irradiation. Therefore, our findings may have biological implications.journal articl
蛍光X 線分析によるイミノ二酢酸キレートディスクへのウラン・ネプツニウム・プルトニウムの保持特性調査
No full textイミノ二酢酸キレートディスク（キレートディスク）は様々な金属元素を吸着する．通常は，吸着した金属元素を溶出させて分析に供するが，蛍光X 線（X-ray fluorescence：XRF）分析法であれば，金属元素を吸着したディスクそのものを分析対象とできる．使用済み核燃料に含まれるアクチニドのうち，ウランのキレートディスクへの保持特性はよく知られているが，ネプツニウムやプルトニウムの保持特性は明らかになっていない．本研究では，ウラン，ネプツニウム，プルトニウムの混合溶液を，様々なpH 条件下でキレートディスクに通液し，そのXRF 分析を行った．ろ紙にこれらの元素を滴下した試料におけるXRF 信号強度との比較により，ネプツニウムとプルトニウムのキレートディスクへの保持特性を明らかにした．journal articl
位相制御2色レーザーパルスの位相差シフトのシングルショット計測
No full text基本波と二倍波のコヒーレントな重ね合わせで得られる2色レーザーパルスは、パルス間の位相差φに依存した非対称な電場波形を持つ。これまでにスペクトル干渉を利用した位相差計測法とフィードバック制御を組み合わせ、単分子解離過程の制御を行ってきた。本研究では、大気中で安価に位相差シフトをシングルショットで計測することを目的とし、マイコンを用いた位相差シフトのシングルショット計測装置の開発を行った。レーザー学会学術講演会第46回年次大会conference presentatio
Frequency characteristics of the liquid Li target flow surface in A-FNS
No full textOne of the key challenges in Advanced Fusion Neutron Source (A-FNS) is to maintain the stable liquid Li target flow over the long-term operation. The laser-based distance meter using an optical frequency comb has been selected to detect the surface disturbance due to the nozzle degradation. However, the laser-based method can measure only wave crests/troughs where the incident laser is reflected. This study evaluated the frequency characteristics of the liquid Li flow surface by interpolating the irregular time series crest/trough data obtained in EVEDA Li Test Loop (ELTL) and performing Fast Fourier Transformation calculations. Linear and sine wave interpolation were performed, and the effect of the interpolation method was evaluated. This study revealed the frequency characteristics of the free surface liquid level fluctuations with the experimental results for the first time. Since a decrease in the spectra intensities due to the rough nozzle surface has been suggested by the calculations, the evaluations in temporal change of the energy spectra could quantitatively detect the nozzle degradation.journal articl