National Institutes for Quantum and Radiological Science and Technology
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QST量医研サイクロトロン(NIRS-930, HM-18)の現状報告
No full text量子科学技術研究開発機構(QST)量子医科学研究所(量医研)のサイクロトロン施設には、1974年に運転開始したNIRS-930 (K=110)と、1994年に運転を開始した放射性核種（RI）生産専用のHM-18(K=20)の、2台のサイクロトロンがある。2021年11月に発生した火災により2台のサイクロトロンは停止したが、2022年9月にHM-18の供給運転を再開した。2024年度のHM-18 は、4月-11月までの期間を運転し、その運転時間は、1054時間であった。残りの期間の12月-3月まではNIRS-930の復旧作業として、受電盤、配電盤や冷却水配管の更新等が行われた。また、NIRS-930用の電磁石電源の製作を行った。本報告では、HM-18の運転状況とNIRS-930の復旧に向けた準備や検討状況等について報告を行う。第22回日本加速器学会年会conference poste
位相制御２色レーザーパルスを用いた電子再衝突による分子励起
No full textPhotoelectron-photoion coincidence momentum imaging has been performed to investigate excitation processes on dissociative ionization of OCS in phase-locked ω+2ω intense laser fields. The electron kinetic energy spectra depend on the ion speicies, OCS^+ or S^+, produced in coincidence. The observed electron momentum distribution shows clear asymmetry along the laser polarization direction with a 2π-oscillation period as a function of the phase difference between the ω and 2ω laser fields. The asymmetry of electron emission in the OCS^+ channel flips at the electron kinetic energy of 8.2 eV, below which forward-scattered electrons dominate and above which backward-scattered electrons dominate. In the S^+ channel, the asymmetry flips at the lower kinetic energy of 4.2 eV. In comparison with a classical trajectory Monte Carlo simulation, it has been clarified that this energy shift between the OCS^+ and S^+ channels corresponds to the excitation energy of the parent ion and that electron recollisional excitation takes place to form the fragment ion in intense laser fields.光・量子ビーム科学合同シンポジウム2025conference poste
Non-destructive visualization of strain and polarization domains in ferroelectric ceramics using coherent X-ray diffraction imaging
No full textUnderstanding the internal strain and polarization domain structures in ferroelectric ceramics is essential for optimizing their dielectric and piezoelectric performance. In this study, we present the application of Bragg coherent X-ray diffraction imaging (Bragg-CDI) for three-dimensional visualization in a non-destructive manner of such mesoscale structures in single nanocrystals [1,2]. Developed at the Harima site of QST, our Bragg-CDI system enables high-resolution imaging of internal strain and domain onfigurations in a particle with a size ranging from 40 to 500 nm [3,4,5]. By combining Bragg-CDI with in situ heating capabilities, we have successfully tracked structural phase transitions and domain evolution under thermal stimuli [6]. This approach provides critical insights into how external factors such as particle shapes and grain boundaries interact with intrinsic mechanisms like phase transitions to affect material properties. A notable example is the 3D reconstruction of 90° polarization domains in a 400 nm BaTiO₃ particle at tetragonal phase [7]; this result reveals domain boundaries and strain distributions that directly impact dielectric behavior. Such mesoscale features are inaccessible by conventional microscopy techniques; therefore, Bragg-CDI has the unique advantage for probing those functional nanostructures. This methodology opens new pathways for the design and evaluation of advanced ferroelectric ceramics. By enabling non-destructive, multiscale structural analysis, Bragg-CDI holds significant promise for accelerating the development of next-generation dielectric and piezoelectric materials.MRM2025conference presentatio
数⼗〜数百 nm サイズ結晶粒の 3 次元⾮破壊イメージング
No full text結晶を原料とした機能性材料は数千数万もの結晶粒で構成され、その機能は結晶粒が相互に成す応⼒やひと粒の外形、粒内部のひずみやドメインなどの構造不均質により⼤きく左右される。微結晶ひと粒を⾮破壊かつ3次元で顕微観察し材料の機能を構造から理解するために、ブラッグコヒーレントX線回折イメージング（Bragg-CDI）法は最も有望な⼿法のひとつである。QSTは⽇本で唯⼀Bragg-CDI法を開発、共⽤しており、40～500 nmサイズの粒⼦の可視化、室温～800 Kでのその場観察、ひずみ‧ドメイン解析の実績がある。本発表では、Bragg-CDI法についていくつかの実施例を提⽰しながら紹介する。第35回 マイクロエレクトロニクスシンポジウムconference presentatio
Emotion regulation: dissecting cortical complexity and neural population dynamics through optical and computational approaches
No full text富山大学Graduate School Seminarにて「Emotion regulation: dissecting cortical complexity and neural population dynamics through optical and computational approaches」の演題で講演を行う。Graduate School Seminarconference presentatio
Overview of Shielding Design and Dose Control Strategies at NanoTerasu
No full textNanoTerasu is the first synchrotron radiation facility in Japan designed to exclude most of the Experimental Hall from radiation-controlled areas by optimizing its shielding design and radiation safety systems. This unique approach allows users who have completed radiation safety training to access and operate synchrotron radiation beamlines without the need for licensing as radiation workers.The shielding design was performed based on semi-empirical approaches, supported by detailed Monte Carlo simulations using PHITS. In addition to the structural concrete shielding that encloses the 3 GeV electron linear accelerator and the electron storage ring, supplementary local shields were installed at specific locations to suppress high-energy bremsstrahlung photons, based on the simulation results. The Experimental Hall is designed to ensure that the effective dose does not exceed 1.3 mSv over a three-month period, assuming 500 hours of working time, even under maximum operating conditions.The radiation safety system consists of two major components: (1) access control and (2) beam current and secondary radiation monitoring, to protect users from radiation exposure. Access is managed using personal dosimeters with QR codes, which radiation workers scan at entry points for authentication. Prior to beam injection, an evacuation confirmation sequence ensures that each interlocked area is unoccupied and securely closed. If an interlock door is opened during operation, the system immediately halts the accelerator. Ambient dose rates behind the shielding are continuously monitored every 10 seconds using several gamma-ray and neutron detectors installed around the radiation-controlled areas and at the site boundary. If the dose rate exceeds a predefined threshold, the system triggers an automatic shutdown. Integrated dose throughout the entire facility is also monitored using several hundred passive dosimeters.This paper reports the radiation monitoring results and dose control measures implemented during accelerator commissioning, following the commencement of user operations in FY2024.The 12th International Symposium on Radiation Safety and Detection Technology (ISORD-12)conference presentatio
Characteristics of passive dosimeters for ultra-high dose rate electrons and protons
No full textUltra-high dose rate radiation therapy, commonly known as FLASH, operates at dose rates over 40 Gy/s, which is 1,000 times higher than conventional radiation therapy (approximately 0.03 Gy/s). This method has garnered significant attention due to its potential to reduce side effects on normal tissue while maintaining therapeutic effectiveness. However, the underlying mechanisms of FLASH therapy remain unclear. It is hypothesized that the sparing effect of FLASH may be linked to the yield of water radiolysis products, which contribute to the radiation’s indirect action in causing DNA damage. To experimentally investigate the effects of ultra-high dose rate irradiation, we examined the dose-rate dependence of the yields of radiation-induced decomposition products in water. To support such research, it is crucial to validate dose measurements when the dose rate varies significantly. Additionally, the differences in detector response due to dose rate definitions such as average dose rate, pencil-beam scanning dose rate, and pulsed dose rate should be verified. In this study, we evaluated dose-rate dependences in various types of passive dosimeters, including optically stimulated luminescence dosimeters, Fricke chemical dosimeters, and cellulose triacetate film dosimeters, using 12 MeV electron pulsed beams and 230 MeV proton scanning beams. An extremely high pulsed dose rate of MGy/s, generated by short electron pulses with a width of 2 µs, induced significant saturation. These results provide valuable insights into acceptable dose and dose rate ranges for FLASH dosimetry.21th International Conference on Solid State Dosimetryconference presentatio
Hydrogenation reactions of Mn-rich alloys studied by synchrotron radiation x-ray diffraction and absorption techniques
No full textwe have tried to synthesize Mn-rich Mn–Al alloy hydrides under high pressure and high temperature. As a result, we found interstitial hydrides MnxAl1-x alloy hydrides (x = 0.9, 0.8, 0.7). In addition, the electronic structures of Mn in the hydrides were investigated using X-ray absorption fine structure measurement at SPring-8, Japan to consider which the interstitial sites hydrogen atoms occupy. In this presentation, we will describe the syntheses of Mn-rich Mn–Al alloy hydrides and the results of analyses of the interstitial sites to occupy hydrogen atom in the hydrides.日本金属学会2025年秋期（第177回）講演大会conference presentatio
バリウム同位体選択的励起導入用DFB-PPLN光源の開発
No full textバリウム同位体は、イオントラップ型量子演算素子での量子ビットの候補となっている。本研究では、バリウムの同位体選択的励起と導入を目指して、553nmの励起用レーザー光源を、分布帰還型レーザーdistributed feedback (DFB) laserと周期的分極反転ニオブ酸リチウムperiodically poled LiNbO3 (PPLN)を用いて開発した。出力は、1107nmDFB基本波が86mW、第２高調波553nmが15mWと、導入に十分な強度が得られた。DFBレーザーの設定温度を変えることにより、出力波長を変化させることが可能である。これに基づき、シングルモードでモード飛びのない波長掃引が示された。これは、バリウムの同位体選択的励起に必要な開発項目である。日本原子力学会2025年秋の大会conference presentatio
Radiosynthesis and Evaluation of Novel 18F Labeled PET Ligands for Imaging Monoacylglycerol Lipase
No full textIntroduction: Monoacylglycerol lipase (MAGL) is a 33 kDa cytosolic serine hydrolase that is widely distributed in the central nervous system and peripheral tissues. Inhibition of MAGL in the brain elevates levels of 2-arachidonoylglycerol and leads to decreased pro-inflammatory prostaglandin. Therefore, MAGL is considered a potential therapeutic target for treating neuropsychiatric disorders, cancer, chronic pain, and inflammation. In this study, we aimed to evaluate a novel class of spirocyclic cyclobutane-lactam scaffolds [18F](R)-6 (codenamed [18F]MAGL-2304) and [18F](S)-6 (codenamed [18F]MAGL-2305) as positron emission tomography (PET)radioligands for imaging of MAGL.Methods: Compounds (R)-6 and (S)-6 and the corresponding precursors 11 were synthesized from commercially available compound 1. The potency and selectivity of (R)-6 and (S)-6 were assessed in human MAGL screening assays. Activity-based protein profiling (ABPP) assays were employed to assess the selectivity of (R)-6 and (S)-6 against other serine hydrolases in mouse brain lysate. In silico properties of compounds (R)-6 and (S)-6 were predicted by ChemDraw 21.0. [18F](R)-6 and [18F](S)-6 were prepared via a Cu-mediated fluorination reaction. In vitro autoradiography experiments were performed on sagittal rat brain, as well as on brain sections from wild-type (WT) and MAGL knockout (KO) mice. PET imaging studies of [18F](S)-6 were performed in Sprague−Dawley (SD) rats. The in vitro stability of [18F](S)-6 was evaluated in serums and liver microsomes from humans and various animal species. Radiometabolite analysis was conducted in the brain and plasma of SD rats. Ex vivo whole-body distribution experiments were carried out in ddY mice at five time points (5, 15, 30, 60 and 120 min) following [18F](S)-6 injection.Results: Compounds (R)-6 and (S)-6 were synthesized with overall yields of 5.1% and 28% over four steps, respectively (Figure 1A). (R)-6 demonstrated an IC50 of 18.57±1.09 nM, while (S)-6 exhibited superior potency with an IC50 values of 1.59±1.08 nM. Both compounds showed no significant inhibition of other lipid hydrolases. LogD values for (R)-6 and (S)-6 were 2.81 and 2.80, respectively, with predicted topological polar surface areas (tPSAs) of 67.87 (Figure 1B). [18F](R)-6 and [18F](S)-6 were synthesized with non-decay corrected radiochemical yields of 13% and 9%, respectively (Figure 1C). In vitro autoradiography demonstrated that [18F](R)-6 and [18F](S)-6 accumulated in the MAGL-rich regions, such as the cortex, hippocampus, striatum, and thalamus. Blocking experiments with KML29 led to a significant reduction of radioactivity (Figure 1D). In MAGL KO mice, [18F](S)-6 uptake was minimal, while wild-type mouse brain showed heterogeneous (Figure 1E). PET imaging study of [18F](S)-6 under baseline conditions exhibited a heterogeneous distribution and the blocking experiments led to moderate reduction in radioactivity uptake (Figure 1F). P-gp inhibition studies suggest that [18F](S)-6 may constitute a P-gp substrate (Figure 1G). [18F](S)-6 exhibited high in vitro stability in serums and liver microsomes as well as formulated in PBS (Figure 1H&1I). In vivo metabolic stability showed the unchanged form of parent [18F](S)-6 constituted 98.6% in the brain and 42.3% in plasma (Figure 1J). Ex vivo biodistribution revealed hepatobiliary and urinary elimination pathways of [18F](S)-6 (Figure 1K).Conclusions: We synthesized and characterized two 18F-labeled MAGL PET ligands, [18F](R)-6 and [18F](S)-6 based on a novel spirocyclic system. (S)-6 (IC50 = 1.6 nM) showed superior binding affinity (IC50 = 1.6 nM) and selectivity than (R)-6. In vitro autoradiography showed [18F](S)-6 demonstrated heterogeneous distribution and specific binding to MAGL-rich brain regions PET imaging studies encompassing P-gp inhibition indicate [18F](S)-6 is subject to P-gp efflux at the BBB. Structural optimization of the spirocyclic MAGL PET ligands is currently underway.SNMMI 2025 Annual Meetingconference presentatio