National Institutes for Quantum and Radiological Science and Technology
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Exploring laser-driven magnetization reversal with terahertz light
No full textIn this research, we developed the high harmonic generation system using an ultrafast laser source (Pharos, Yb:KGW laser) and applied the system to transmission measurements of thin films.OPTO2025conference poste
Remarks on beryllium nuclear data for fusion reactors
No full textBeryllium, 9Be, is an important functional material for a fusion blanket as a neutron multiplier and moderator and will be irradiated in test modules at the Advanced Fusion Neutron Source (A-FNS) to obtain the neutron irradiation characteristics data. However, the nuclear data of beryllium has been suspicious by several integral experiments.JAEA/FNS carried out an integral experiment with a thick beryllium assembly with DT neutrons 30 years ago. It has been reported to date that analyses of this experiment largely overestimate the measured data sensitive to low energy neutrons even if the latest nuclear libraries are used, though they rather agree with the measured data sensitive to neutrons above 1 MeV.Recently, the European Spallation Source group produced new thermal neutron scattering law data of beryllium with different crystallite sizes, whose cross sections were different due to the extinction effect. In this study, we adopted the thermal neutron scattering law data of beryllium with different crystallite sizes for the analysis of the JAEA/FNS beryllium experiment with MCNP-6.20 and JENDL-5. As a result, the overestimation of the measured data sensitive to low energy neutrons decreased with increasing crystallite sizes. It demonstrates that the thermal neutron scattering law data of beryllium without the extinction effect cause the overestimation.In this study, we also found another issue on beryllium. The calculated reaction rates of the 115In(n,n’)115mIn reaction sensitive to neurons above 350 keV are clearly different among JENDL-5, JEFF-3.3 and FENDL-3.2c. We also examined this issue and specified that the secondary neutron spectrum in the (n,2n) reaction caused the discrepancy.The secondary neutron production data in the (n,2n) reaction of 9Be should be revised and the thermal neutron scattering law data of beryllium considering the extinction effect should be added to the next FENDL.Fusion Neutronics Meeting 2025: ITER and beyondconference presentatio
ESRによる高分子用酸化防止剤の検討
No full text【序論】高分子製品には複数の酸化防止剤が添加されている場合がある。我々はヒンダードフェノールやヒンダードアミンに分類される酸化防止剤が安定ラジカルを生成することに着目し、ESRによりそれらの消長を評価することで高分子材料の寿命予測の可能性を検討している。今回、太陽電池モジュールの封止剤に添加された酸化防止剤ラジカルの検討を行った。【実験】1. 試料 封止剤①エチレン-酢酸ビニル共重合体(EVA)系，②ポリオレフィン系 共に未処理品と紫外線強度500W/m2で加速劣化したもの2. 添加剤 ①ベンゾフェノン系紫外線吸収剤(BP)，ヒンダードフェノール系酸化防止剤(HP)，ヒンダードアミン系光安定剤(HA)，その他（架橋剤、可塑剤）。②ベンゾトリアゾール系紫外線吸収剤(BT)，BP，リン系酸化防止剤，HP。3. ラジカル評価 封止剤の加速劣化品はそのまま、未処理品および酸化防止剤（トルエン溶液）はESRセルに入れHg-Xeランプを照射しながら測定した。【結果と考察】両封止剤の72 hr加速劣化品の測定した結果、共にg = 2.0063を与え3本の同等の分裂を示したことから同等のN由来ラジカルと推定された。未劣化品を光照射しながら測定した場合も同等のスペクトルが観測された。このことは、②に①と同等の含N酸化防止剤が含まれている事を示唆している。しかしながら、BT試薬溶液を光照射測定したところラジカルは観測されなかった。この理由は明確ではないが、封止剤中でBTが何らかの変性を起こしている可能性があると推測される。第28回ESRフォーラム研究会conference poste
Reflected Picosecond Laser Pulse Driven Boosted Coulomb Explosion for Quasi-Monoenergetic Deuteron Production
No full textWe present recent progress on generating quasi-monoenergetic deuterons using the petawatt LFEX laser. A key development is our in-situ fabrication of D2O-deposited targets within the laser chamber, using heavy water capsules to form nanometer-thick D2O layers on metal surfaces. These targets enabled quasi-monoenergetic deuteron pulses (ΔE/E = 4.6%) via the Target Normal Sheath Acceleration (TNSA) mechanism, though the energy peaked at ~11 MeV due to proton influence on beam structure. To overcome this limit, we introduced a novel mechanism, boosted Coulomb explosion, triggered by a standing wave in pre-expanded plasma. This stading wave results from the interference of the incident laser and its reflection from a solid target, enhancing deuteron acceleration. Using this method, we achieved quasi-monoenergetic deuterons with energies up to 50 MeV from the target front side. Moreover, the deuteron peak energy is shown to be tunable via laser pulse duration.日本物理学会 第80回年次大会conference presentatio
Correction method for large scattered-neutron background in capture cross-section measurements
No full textIn neutron capture cross-section measurements by the time-of-flight (TOF) method using pulsed neutron beams, some of the neutrons scattered within the sample are captured by structural materials around the detector, resulting in the emission of capture gamma-rays. The emitted gamma-rays induce background events (hereinafter referred to as “scattered-neutron background”), and this background must be subtracted from TOF data in analysis to accurately derive the capture cross-section. The Accurate Neutron-Nucleus Research Measurement Instrument (ANNRI) is installed at beamline No.4 of the Materials and Life Science Experimental Facility in the Japan Proton Accelerator Research Complex to measure nuclear reaction. The ANNRI is equipped with large NaI detectors and has been used to perform many capture cross-section measurements. Recently, the authors have attempted to measure the capture cross-sections of structural materials such as iron, nickel, and chromium, which have very large neutron scattering resonances compared to capture cross-section. As expected, the scattered-neutron background of these nuclides has a significant impact on applying the conventional correction method. Through Monte-Carlo simulations using the PHITS code, it was confirmed that neutrons with energies above 100 keV can induce background events with a time-delay between scattering in the sample and detection up to 100 us. This means that neutrons scattered at the resonance form a background in the TOF region slower than the resonance. Without considering the time delay in the resonance scattering, the scattered-neutron background in the resonance region is overestimated and the scattered background in the slow TOF region is underestimated. In addition, the delayed scattered-neutron background with higher energies has also to be considered. Therefore, the conventional correction method for scattered-neutron background cannot be applied, and it is necessary to develop the new methodology that accounts for this time delay. In this presentation, we will report on our current efforts to implement a new correction method to the capture cross section measurement data at ANNRI. Moreover, preliminary results of the Cr-50 neutron capture cross-section using this new methodology will also be presented.16th Nuclear Data for Science and Technology Conference (ND2025)conference poste
Effects of Electron Irradiation and Anneal Condition on Creation of Nitrogen-Vacancy Centers in Ib Diamonds
No full textElectron irradiation is one of the most powerful methods to create negatively charged nitrogen-vacancy centers (NV-s) in diamonds, which act as qubits and quantum sensors even at room temperature (RT). For quantum sensing, it is important to create ensemble NV-s with long coherence time (T2) since the sensitivity can be affected by both amount of NV- and T2. For high concentration NV-, electron irradiation with higher fluence is needed. However, if electron fluence is too high, neutral NVs (NV0s) are created because of lack of N donors. For T2, since residual defects act as origins of T2 decoherence, it is important to optimize the condition of subsequent annealing as well as irradiation fluence. Thus, we need to consider initial nitrogen (P1) concentration in diamond, electron fluence, and annealing conditions. In this paper, we create NV-s in Ib diamonds by electron irradiation and subsequent annealing with different conditions, and study the amounts of NV-s and their T2 for high-sensitive quantum sensing. The samples used in this study were Ib diamond with P1 concentration around 100 ppm. Those samples were irradiated with 2 MeV-electrons at a fluence of 1x1018/cm2 at RT. After irradiation, the samples were annealed between 600 and 1400oC in Ar. Photoluminescence (PL) measurements were carried out at RT to confirm NV creation. For PL measurements, the laser with a wavelength of 532 nm was used as excitation. PL intensity for samples annealed at 600 oC is about half even after annealing for 600 min, comparing with that for 800 oC-annealed samples although the values increase with increasing annealing time. Thus, the annealing at 650 oC is not enough to create NV. The samples annealed between 800 and 1200 oC show the highest PL intensity even after annealing for 10 min. The 800 and 1000 oC-annealed samples keep the PL intensity after annealing for 1200 min although the PL intensity for 1200 oC-annealed samples decrease with increasing annealing time above 100 min. The PL intensity for the samples annealed at 1400 oC shows smaller value and decreases with increasing annealing time. For T2, the samples annealed at 1400 oC show 2 microsec after annealing for 10 min. However, NV- cannot be observed after annealing at 1400 oC for 30min. Therefore, it can be concluded that annealing at 1400 oC is not suitable for the creation of NV-. For samples annealed between 600 and 1000 oC, the values of T2 are constant (between 0.5 and 0.9 microsec) after annealing up to 1200 min. For samples annealed at 1200 oC, no significant difference in T2 value is observed from those annealed between 600 and 1000 oC up to 30min, and the value increases with increasing annealing time above 30 min. From the point of view of sensing, it is important to consider both the amounts of NV- centers and T2. Therefore, we compare the values of PL intensity times T2. As a result, the samples annealed between 800 and 1200 oC show the highest value although the value for samples annealed at 1200 oC decreases after annealing for 1200 min. This suggests that annealing at 800 oC for 10 min is enough to create NV-s. We also study the creation of NV-s in diamonds by electron irradiation at elevated temperature. The samples with P1 concentration around 60 and 100 ppm were irradiated with 2 MeV-electrons at fluences up to 5x1018/cm2 at 800 or 1000 oC. The samples were annealed at 1000 oC for 120 min after irradiation. The amounts of NV are estimated from electron spin resonance (ESR) signals. As a result, samples irradiated at 800 and 1000 oC show higher NV- concentration than that for RT-irradiated ones, and 800 oC-irradiated ones show higher NV concentration than 1000oC-irradiated ones. Since the T2 values are not affected by irradiation temperature, the elevated temperature irradiation, especially 800 oC irradiation is a useful method to realize quantum sensing with high sensitivity.75th UK Diamond Research Conferenceconference presentatio
NanoTerasu BL02U 超高分解能RIXSの現状
No full textNanoTerasu BL02Uの2D-RIXSは世界最高のエネルギー分解能を達成し、2025年3月から共用が開始された。2D-RIXSの性能の現状について紹介する。科研費研究会「超100K級銅酸化物高温超伝導体の物理」conference presentatio
Novel grafted adsorbents for the removal of Gd-based contrast agent' derivatives from aqueous media
No full textGadolinium (Gd)-based contrast agents used in MRI investigations are structured with strong chelate bonds to ensure safety from human administration to excretion. On the other hand, this Gd contrast agent is widely discharged into the environment after MRI investigations. After passing through sewage treatment facilities and being discharged into the environment, it denatures as highly toxic Gd3+ ions, which accumulate in aquatic organisms and have a high potential to affect biological life. This anthropogenic Gd was first observed in a German river in 1996, suggesting that the main component was derived from MRI contrast media. However, acceptable concentration levels of Gd in aqueous media have not been established, raising concerns about future environmental contamination.We would like to propose a novel method to introduce chelating groups onto conventional polymeric materials. As one of the methods to remove Gd contract agent derivatives from water body, we examined an adsorbent material with iminodiacetic acid groups introduced by radiation-induced graft polymerization (RIGP). RIGP has the advantage that general-purpose polymer materials with various shapes and properties can be freely selected, and desired functions can be introduced at high density. In this study, we report on the evaluation of the stability of Gd contrast agents and the characterization of Gd-adsorbent that can adsorb Gd, aiming at the establishment of a Gd removal technique form the environment.The 19th Pacific Polymer Conferenceconference poste
Hysteresis of amplitude-frequency relationship of MHD instabilities and its modeling in toroidal magnetically confined plasmas
No full text環状磁場閉じ込めプラズマでのMHD不安定性による磁場揺動の振幅と周波数の関係を調査し、モデル化することで、将来装置での振幅や周波数の予測を目指している。従来、周波数増加時と減少時の軌跡は一意であり、加速粘性力と減速電磁力とのバランスで説明される。JT-60Uにおいて新古典テアリングモードが発生している放電でヒステリシスを伴う軌跡を発見した。周波数減少時は不安定性駆動の渦電流による摂動磁場に基づく減速電磁力が支配的であり、一方、周波数増加時は外部コイルによる摂動磁場による減速電磁力が支配的であるモデルを提案した。JT-60Uの典型的な時定数を用いたモデルにより観測されるヒステリシスを再現できた。51st EPS Conference on Plasma Physicsconference poste
[211At]MABGの体内分布制御法の開発
No full text標的α線治療薬による副作用をできる限り抑え、強い抗腫瘍効果を達成するため、我々は既承認医薬品の併用による標的α線治療薬の体内動態制御法の確立を目指している。本研究では、標的α線治療薬として211At標識メタアスタトベンジルグアニジン（[211At]MABG）に着目し、[211At]MABGの腫瘍集積増強に有用な薬剤を細胞実験によって検討した。本研究では、ヒト神経芽腫細胞株（SK-N-SH及びSK-N-BE(2)c）を使用した。各細胞に対し、文献調査により選抜した[211At]MABGの細胞内取込みを高める可能性のある薬剤（20種）を処置した後、[211At]MABGを加え6時間培養後した。その後、細胞を洗浄・溶解し、放射能を測定した。SK-N-SHでは、ブロモクリプチン、グルカゴン、ミドスタウリン、パキサリシブ処置により、[211At]MABG取込みが増加した。SK-N-BE(2)cでは、ドキソルビシン、フィメピノスタット、パキサリシブ処置により、[211At]MABG取込みが増加した。今後、細胞実験で選抜した薬剤の有用性を動物実験にて検証する予定である。第６５回日本核医学会学術総会conference poste