National Institutes for Quantum and Radiological Science and Technology
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高強度赤外光源開発とそれを用いた軟X線高次高調波発生
No full textYbYAG薄ディスクレーザーを用いた高強度赤外光源開発とその応用実験としての軟X線高次高調波発生について発表する。第48回ATTO懇談会conference presentatio
光と機械学習で読み解く「記憶・こころ」の脳神経細胞ネットワーク
No full text熊本大学医学教育部のセミナーにて「光と機械学習で読み解く「記憶・こころ」の脳神経細胞ネットワーク」の演題で発表を行う。熊本大学医学教育部でのセミナーconference presentatio
全身用Whole Gamma Imaging装置の設計：シミュレーションによる性能予測
No full textPETリング内に散乱体検出器リングを設置することで、PETとコンプトンイメージングを融合したWhole Gamma Imaging (WGI）の実現を目指している。本研究では、陽電子放出核種Zr-89を用いたイメージングのための全身用WGIを設計した。Geant4を用いたシミュレーションにより、散乱体直径と吸収体直径が角度分解能とコンプトン感度に与える影響を評価し、最適な検出器径を選定した。計測自動制御学会 ライフエンジニアリング部門シンポジウム2025conference presentatio
High-Repetition Laser-Driven Heavy Ion Bunches for the Quantum Scalpel Injector
No full textLaser-driven ion acceleration has gained significant attention as a next-generation acceleration technology, offering key advantages such as compactness, high accelerating electric fields, and short pulse durations. In this study, we aim to realize a novel accelerator system called the Quantum Scalpel, which combines a laser-driven heavy ion injector with a superconducting synchrotron accelerator. The Quantum Scalpel is expected to contribute to the broader deployment of heavy ion cancer therapy by enabling compact treatment systems that can be installed within existing hospital infrastructures.This presentation reports on the development of a laser-driven ion injector capable of 10 Hz high-repetition operation using carbon ions, a representative heavy ion species. Ion acceleration was achieved by irradiating thin foil targets with a high-intensity femtosecond laser, utilizing the Target Normal Sheath Acceleration (TNSA) mechanism. To support continuous high-repetition operation, we implemented automated target delivery, debris shielding, and optimization of laser temporal contrast. These improvements collectively enabled stable and sustained generation of heavy ion bunches suitable for injection into downstream accelerator stages.The 5th Nuclear Photonics Conferenceconference presentatio
Progress of assembly and installation of LIPAc SRF Cryomodule under the EU–JA Collaborative Framework
No full textThe commissioning of LIPAc (Linear IFMIF Prototype Accelerator) is ongoing at QST Rokkasho Institute for Fusion Energy within the engineering validation of the accelerator system up to 9 MeV/125 mA in continuous wave under international collaboration between Japan and Europe. Several SRF cryomodules will be required for IFMIF to accelerate deuterons from 5 MeV to 40 MeV. The prototype of the first of these cryomodules has been manufactured and will be installed and tested on the LIPAc. It holds the eight Half Wave Resonator and RF couplers to accelerate the beam and the eight superconducting solenoids to focus it.During the cryomodule assembly, several non-conformities were identified, including vacuum leaks and cryogenic pipe issues. These challenges were addressed through a coordinated effort involving Japanese and European partners. Solutions included the refabrication and repair in Japan of critical components, adhering to Japan’s High Pressure Gas Safety Act and international standards. Material selection, thermal cycling treatments, magnetization assessments, and regulated welding with non-destructive tests (pressure and penetration) were jointly implemented. This poster outlines the technical approaches taken, highlights the collective efforts of the LIPAc team in resolving the encountered issues, and reports on the progress toward the successful assembly and validation of the LIPAc SRF cryomodule.22nd International conference on RF superconductivityconference presentatio
Evaluation and prediction of Creep-fatigue lifetime of F82H for Water-Cooled Ceramic Breeder Test Blanket Module Application
No full textA reduced activation ferritic martensitic (RAFM) steel known as F82H is the primary candidate for structural materials in the water-cooled ceramic breeder test blanket module (WCCB TBM) for ITER. Given that the WCCB TBM experiences cyclic loads from cooling water pressure, heat load, and electromagnetic forces within the temperature range where F82H is susceptible to creep, a quantitative investigation of the creep-fatigue (CF) lifetime for this material is essential. For a new material like F82H, developing a CF lifetime curve requires substantial time and extensive data. This study aims to evaluate and predict the CF lifetime of F82H by combining limited CF experimental results with a strain-range partitioning method. Additionally, a novel approach is proposed based on these findings and similar steel grades, such as 9Cr-1Mo-V, to predict the CF lifetime of F82H. The experimental work involves a round-bar CF specimen with a gauge section measuring φ5 mm x 12 mm, as specified in ASTM E2714-13. Tension-comparison tests are conducted at 550°C in air, featuring a stress ratio of R = -1 and a strain rate of 10^-1 %/s. The total strain ranges from 0.75% to 1%, with a holding duration of 180 seconds per cycle at the peak compressive stress. Using the experimental data and the strain-range partitioning method, constitutive relations for evaluating the CF lifetime of F82H are formulated. The predicted lifetime aligns with experimental results by a factor of two. The specifics of the CF lifetime evaluation and prediction for F82H will be presented in detail.22nd international conference on fusion reactor materialsconference poste
Long-lived density spikes in laser-driven Coulomb explosion folds
No full textA relativistically intense femtosecond laser pulse passing through subcritical gas jet plows away all electrons in its path and creates multi-stream flows in the electron distribution. These flows exhibit folds and cusp singularities that were proposed as nano-scale sources of x-ray radiation. Recently, PIC simulations in a simplified 2D setting indicated that the ensuing Coulomb explosion of the trailing ions also produces multi-stream flows with ring-shaped cusps and associated long-lived spikes in the ion distribution. This has now been confirmed using self-consistent 3D PIC simulations. Extensive parameter scans (w.r.t. density, ion mass, temperature, laser intensity, Rayleigh length, pulse shape) were performed to clarify the conditions for the formation of such long-lived structures in the ion distribution. While a Gaussian laser pulse produces off-axis density spikes that are diluted via radial expansion in 3D, a donut-shaped Gauss-Laguerre pulse is shown to produce on-axis density spikes that are enhanced by an order of magnitude. Applications for this fundamental research are currently being sought.2025年度AAPPS-DPP研究会conference presentatio
Prediction of tumour hypoxia by range-verification PET in particle therapy: Proof-concept in rats
No full textAbstract— Tumour hypoxia, highly influenced by tumour vasculature status, has an important implication for tumour response to radiation therapy. While tumour hypoxia status is changing during a treatment period, hypoxia PET is impractical to perform in every fractionated irradiation. On the other hand, there is a chance to extract tumour hypoxia information from the biological washout in range-verification PET, by detecting irradiation-produced positron (β+)-emitting nuclides. However, it is not clear whether the blood flow supply and washout can reflect the tumour oxygen status. Therefore, this study aimed at obtaining conclusive evidence in hypoxic tumour rat models by comparing results for range-verification PET and hypoxia PET. Glioma C6 cancer cells were transplanted into nude rats. Tumours were irradiated with a 12C ion beam, and range-verification PET was performed by a high sensitivity total-body small-animal PET system. Then the rats underwent PET imaging with a hypoxia tracer, 18F-FAZA, for tumour diagnosis. The parametric maps of washout rate obtained with range-verification PET were in good agreement with 18F-FAZA-PET images. This study demonstrated the biological washout-based diagnosis for tumour hypoxia in routine range-verification PET.2025 IEEE NSS MIC RTSDconference presentatio
大容量試料溶液保持加工を施した基板を用いた高感度TXRF分析
No full text液体試料の全反射蛍光X線分析では、ガラス基板に10 μLほどの試料溶液を滴下し、乾燥させて分析に供するのが一般的である。これに対して、親水性スライドガラスの中心6 mmほどの円形部分の外側を撥水加工することで、1 mLの溶液を滴下し、乾燥させて分析を行うことが可能となった。単純計算で検出感度は従来の方法に比べて100倍に向上することになるが、実際には70倍程度となった。第61回X線分析討論会conference presentatio
Creation of highly charged gold ion beam through collisional ionizations in a dense gold plasma driven by a femtosecond petawatt laser
No full textNumerical investigations of the ionization mechanisms in the high-temperature high-density gold plasma formed by a high contrast high-intensity laser pulse interacting with gold foil are performed to investigate high-efficiency gold ion acceleration with few PW-level laser systems, aiming at producing ≳ 10 MeV/u gold beams required to serve as an alternative to the front end of a conventional heavy ion accelerator complex such as an ion source, linac, and drift tube linac (DTL). Short pulse high-intensity laser pulses with a peak intensity of a few times 1022 Wcm−2, which is not strong enough to expel Au L-shell electrons by laser field ionization, are shown to sufficiently resistively heat up the target bulk temperature so that collisional ionization by electrons in the plasma can expel L-shell electrons. The resultant highly charged Au ions (∼+72±4) are exposed to the sheath field and accelerated to higher energies of ∼20 MeV/u.QST International Conference on “Future Prospects of Quantum Science and Technology Using Laser-based Soft X-ray and Synchrotron Radiation”conference poste