National Institutes for Quantum and Radiological Science and Technology
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Pt/Ti, Pt/TiN電極を有した4H-SiC MOSFETsの500℃10時間加熱試験
No full text自動車や電力産業, 宇宙開発など高温環境下で動作可能な炭化ケイ素（SiC）集積回路実現に向け、高融点金属である白金（Pt）、チタン（Ti）、窒化チタン（TiN）を配線に用いた４H-SiC nおよびp型 電界効果トランジスタ（MOSFET）を作製し、500℃10時間の加熱試験を行った。加熱後もSiC MOSFETはトランジスタ動作したが、動作電圧であるしきい値電圧や電子の移動度が変化した。これは過去の報告にあるように、400℃を超えるとSiC表面の炭素原子が基板-配線間のニッケル/ニオブ（Ni/Nb）コンタクトに拡散し、抵抗値が上昇したためと推測される。また加熱後の移動度変化はPt/TiNを配線に用いた時の方が小さいことが確認された。先進パワー半導体分科会 第12回講演会conference poste
Recent Progress of Dissimilar Material Bonding Technique with Spark Plasma Sintering Method for High Heat Load Plasma Facing Components in Reactor-Relevant Devices
No full textIn National Institute for Fusion Science (NIFS), dissimilar material bonding technique using Spark Plasma Sintering (SPS) method has been developed to join the high heat load armor to the heat sink in target plates of the divertor component in fusion experimental devices. Tungsten (W) which is the first candidate of the divertor armor material in fusion reactors has been tried to bond to various heat sink materials, i.e., copper ally (CuCrZr), molybdenum alloy (TZM), stainless steel (SS), graphite or carbon fiber reinforced composite (C/CFC). Up to now, the W-CuCrZr bonded divertor tile for LHD succeeded in the heat load test with e-beam of 23 MW/m2, quasi steady-state (10 minutes) and of 15 MW/m2, 10 sec, 100 times cyclic (duty cycle = 50 %). In order to evaluate the bonding performance, diagnostics with SEM/EDS on the bonding surface, together with the shear stress test were performed. In the paper, recent progress of research and development for dissimilar material bonding with SPS are overviewed.30th IAEA Fusion Energy Conference (IAEA FEC 2025)conference poste
微細構造および弾性率を制御した基板上の細胞運動とERK活性の相関解析
No full text幹細胞は分化能と自己複製能を有することから再生医療応用が期待される．再生医療応用には，幹細胞の正確かつ効率的な分化制御法が求められているが，その増殖・分化の切り替えに担う仕組みは十分に解明されていない．Notch や ERK に代表される細胞内シグナルの振動が，分化・増殖の切り替えに関与していることが分かってきているものの，細胞内外の物理的な因子とシグナル伝達との相互作用は不明なことが多い． そこで本研究では，細胞内シグナル伝達と物理因子との相互作用を明らかにすることを目的とし，培養基板の微細構造がERKのシグナル振動に及ぼす影響を検討した．ラドテック研究会 第1回若手ポスター発表会conference poste
Multi-ion beam irradiation combined with KRASG12C inhibitors effectively destroys KRAS mutant lung cancer cells
No full textKRAS mutations occur primarily in the non-small cell lung cancer (NSCLC), and the presence of KRAS mutations is associated with poor prognosis. In this study we investigate the effects of a multi-ion (He-, C-, O-, Ne-) beam irradiation (IR) alone or in combination with KRASG12C inhibitors (sotorasib, adagrasib) on NSCLC cells. We found that LU99 (KRASG12C mutant) and A549 (KRASG12S mutant) cells were resistant to He and C-ion beam IR, but sensitive to Ne-ion beam IR, which was ineffective when combined with sotrasib or adagrasib. In contrast, LU65 (KRASG12C mutant) cells were sensitive to treatment with C-, Ne- and O-ion beam IR alone, and was further enhanced when combined with sotorasib or adagrasib, whereas LU99 cells were killed by C-, Ne-ion beam combined with relatively high dose of sotorasib or adagrasib. Furthermore, C-, and Ne-ion beam IR in combination with sotorasib significantly enhanced the expression of the apoptosis- and autophagy-related genes such as cleaved-caspase3 and ATG7. Taken together, combination of heavier ions such as Ne-ion IR, with KRAS12C inhibitors likely induces KRASG12C mutant NSCLC cell death more significantly.第 84 回日本癌学会学術総会conference poste
IFMIF原型加速器の現状と超伝導加速器の研究開発
No full text第18回量子エネルギー工学フォーラムにおいて、IFMIF原型加速器（LIPAc）の超伝導加速器の研究開発に関する現状及び課題等についてポスター発表する。第18回 量子エネルギー工学フォーラムconference poste
イオンビームグラフト重合法による製塩用アニオン交換膜の開発
No full textイオンビームグラフト重合法により、フッ素樹脂を基材としてアニオン交換膜（AEM）を作製し、電気透析性能と関わる電気抵抗と水透過率を測定した。照射イオン種とAEMのイオン交換容量に応じて、抵抗と水透過率を広範囲で制御でき、市販膜よりも低い抵抗と低い水透過率の両立も達成した。日本膜学会膜シンポジウム2025conference presentatio
宇宙環境における二次中性子シングルイベント効果の低減に資する遮蔽構造
No full text銀河宇宙線・太陽粒子線によって構成される宇宙放射線はそのほとんどが高エネルギーの荷電粒子である。一方で、ISSをはじめとする有人環境では荷電粒子の相互作用によって生成する中性子も存在し、これらは半導体デバイスのシングルイベント効果に寄与する。本研究では様々な組成からなる宇宙機構造を仮定し、中性子によるエラー率を数値シミュレーションによって評価するとともに、これを低減する遮蔽構造について議論を行う。第69回宇宙科学技術連合講演会conference presentatio
Comparison Experiment of Dispersion for Atmospheric Tritium using ROPUCO and UFOTRI models
No full textNowadays, a new atmospheric dispersion code for tritium, ROkkasho PUff COde (ROPUCO), based on the Gaussian Puff model has been developed for assessing A-FNS, a fusion neutron source facility in Japan. To validate and improve the efficiency of this code, it is essential to compare its performance with other established models. In this study, compared ROPUCO model with UFOTRI model which a widely used code developed in Germany that applies a Gaussian Plume model. The comparison shows that the two models produce similar dispersion patterns and concentration distributions, confirming the consistency and reliability of ROPUCO for use in future tritium safety evaluations and emergency response planning.JSST2025 The 44th International Conference on Simulation Technologyconference poste
ELUCIDATION OF THE MECHANISMS UNDERLYING ULTRA-HIGH DOSE RATE IRRADIATION
No full textBackground and AimsIt was indicated that radical-radical interactions between different tracks located at the closest locations, and sudden and local reduction of oxygen concentration were one of the mechanisms of the sparing effects of tissues under UHDR irradiation. To elucidate the mechanisms of biological effects under ultra-high dose rate (UHDR) irradiation, we have addressed radiation chemistry and radiation biology experiments.MethodsTo understand the mechanisms of UHDR irradiation, we evaluated changes in yields of water radiolysis species (i.e., OH radicals, hydrated electrons and hydrogen peroxide), and strand breaks of pBR322 plasmid DNA under clinical energy protons in an average dose rate range from 0.1 to 50 Gy/s. Here, the concentration of OH radical scavenger, Tris-HCl solution, was varied from 10 to 900 mM to investigate the contribution of OH radicals for DNA strand breaks.ResultsPrimary yields of OH radicals and hydrated electrons decrease monotonically with increasing dose rate. In comparison, yields of hydrogen peroxide increase very slightly with dose rate, when we add methanol and sodium nitrate, both of which are scavengers of OH radicals and hydrated electrons, respectively, that decompose hydrogen peroxide formed by water radiolysis. No significant dose rate dependence of DNA single strand breaks is seen at the Tris-HCl concentration of 10 and 100 mM, corresponding the scavenging time scale of 9 and 90 ns. In comparison, a significant reduction is observed at 900 mM (i.e., scavenging time scale of 1 ns).ConclusionsThe present findings implied that radical-radical reactions occurred in the early chemical stage (~ 10 ns) contribute to the reduction of DNA damage, leading the sparing effects of healthy tissues.FRPT2025conference poste
iNIPAMゲル線量計を用いた低エネルギーX線照射に対する線量応答性の評価とハンドヘルド蛍光X線分析装置の誤用による被ばく事故の際の線量評価への応用
No full text出力が自動設定であるために線量計測が困難なハンドヘルド蛍光X線分析装置からのX線により被ばく事故が発生した際の線量評価を、人体等価なiNIPAMゲル線量計で行う手法を開発した。従来のNIPAMゲルにMgCl2を添加したiNIPAMゲルの線量応答性を調査し、低エネルギーX線における増感効果を初めて明らかにしたほか、ハンドヘルド蛍光X線分析装置からのX線の線量計測に成功した。日本保健物理学会第58回研究発表会conference poste