National Institutes for Quantum and Radiological Science and Technology
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Comparison of remote access technologies for research facilities using EPICS/CSS. Application to particle accelerator experiments
No full textThis study compares and proposes new alternatives for remotely connecting to visualize the experimentsoccurring in a particle accelerator located in Rokkasho, Japan. Three different platforms have been consideredfor remote access: the existing X2GO client, Guacamole with Control System Studio (CSS), and Phoebus web.While X2GO is a standard client for remote access to a server desktop, the other two platforms are proposed toimprove the access, the response time, and the user experience for the researchers The servers for this study andthe Operator Interfaces (OPIs) have been placed in our laboratory located in Granada, Spain, and the acceleratordata, by means of Process Variables (PVs), were obtained via a VPN. Additionally, these platforms have beentested in two ways: with direct access to the PV data for each connection and using a local EPICS (ExperimentalPhysics Industrial Control System) Gateway. The results prove that these new platforms, with a stable connectionto the accelerator, could eventually enhance access to the experiments and balance the load of researchersconnecting to the facility. This would allow the international team of researchers to participate in experiments asif they were physically in the control room.journal articl
国際トカマク物理活動（ITPA）に関する報告「閉じ込め・輸送」
No full text閉じ込め・輸送及び核燃焼プラズマ統合コード研究会会にて、日本コミュニティへのITPA活動の周知、閉じ込め輸送トピカルグループの最近の研究活動や重要な研究項目を紹介し、国内装置からの貢献可能な研究提案について議論する。具体的には、ジャイロ運動論シミュレーションを用いたトカマクプラズマの乱流安定性解析、プラズマ周辺部の密度や温度の分布モデリング、重水素と軽水素プラズマの輸送の違いによる密度や温度分布のモデリング、LHDで観測された密度と温度分布への乱流輸送の影響、ITERでの閉じ込めと輸送研究の課題として、高エネルギー粒子のバルク粒子の輸送への影響、電子加熱支配下での乱流とプラズマ分布の理解を報告する。閉じ込め・輸送及び核燃焼プラズマ統合コード研究会conference presentatio
SPATIAL POLARIZATION DISTRIBUTION MEASUREMENTS OF GAMMA RAYS PRODUCED BY INVERSE COMPTON SCATTERING
No full textHighly polarized MeV gamma rays produced via inverse Compton scattering (ICS) between a polarized laser and electron beam provide a unique probe for fundamental and applied physics. ICS gamma rays are characterized by energy tunability, quasi-monochromaticity, high polarization, and low divergence angle (<1 mrad), and are used for accelerator beam diagnostics, nuclear physics experiments, and evaluation of detectors for polarized gamma rays. A polarimeter that can measure the spatial polarization distribution of gamma rays is being developed at the UVSOR synchrotron facility. The measurement principle exploits the azimuthal asymmetry in Compton scattering cross-sections. Incident linearly polarized gamma rays interact with an iron target. Seven NaI detectors arranged in the scattering plane record the angular intensity distribution of scattered gamma rays. The determination of the polarization axis is achieved through systematic analysis of the azimuthal modulations. The spatial polarization distribution is measured by scanning a 1-mm diameter collimator in the beam cross-section in two dimensions. Here, we discuss the results of the gamma-ray polarization axis measurement relative to the laser polarization axis measured when the collimator position is along the central axis of the gamma-ray beam.conference pape
Pulsed EPR Spectroscopic Study on the Kinetics of Photo-Generated Free Radical Reactions
No full textA pulsed EPR method monitoring spin echo signals of free radicals has been applied to measure radical scavenging reactions in the solution phase. We will review our recent studies on various radical reactions. Radical scavengers examined here are various conventional monomer compounds widely used in polymer chemistry, and some radical scavengers such as phenols, fullerenes and trithiocarbonate-type compounds known as RAFT agents for living radical polymerization. Identification of radical reaction products has been made by the time-resolved EPR methods as well as spin-echo-detected EPR and FT-EPR methods. Radical reaction dynamics will be argued on the basis of the rate constants.18th DAE-BRNS Biennial Trombay Symposium on Radiation and Photochemistry (TSRP-2026)conference presentatio
Design optimization using GATE Monte Carlo simulations for a sub-0.5 mm resolution PET scanner with 3-layer DOI detectors
No full textObjective. For rodent brain PET imaging, spatial resolution is the most important factor for identifying small brain structures. Previously, we developed a submillimeter resolution PET scanner with 1 mm crystal pitch using 3-layer depth-of-interaction (DOI) detectors. However, the spatial resolution was over 0.5 mm due to a relatively large crystal pitch and an unoptimized crystal layer design. Here we use Geant4 Application Tomographic Emission (GATE) Monte Carlo simulations to design and optimize a sub-0.5 mm resolution PET scanner with 3-layer DOI detectors. Methods. The proposed PET scanner has 2 rings, each of which has 16 DOI detectors, resulting in a 23.4 mm axial coverage. Each DOI detector has 3-layer lutetium yttrium orthosilicate crystal arrays with a 0.8 mm crystal pitch. We employed GATE Monte Carlo simulations to optimize three crystal layer designs, A (4 + 4 + 7 mm), B (3 + 4 + 4 mm), and C (3 + 3 + 5 mm). Spatial resolution and imaging performance were evaluated with a point source and resolution phantom using analytical and iterative algorithms. Main results. Among the three designs, design C provided the most uniform spatial resolution up to the radial offset of 15 mm. The 0.45 mm diameter rod structures were resolved clearly with design C using the iterative algorithm. The GATE simulationresults agreed with the experimental data in terms of radial resolution except at the radial offset of 15 mm. Significance. We optimized the crystal layer design of the mouse brain PET scanner with GATE simulations, thereby achieving sub-0.5 mm resolution in the resolution phantom study.journal articl
理論と第一原理計算による加工現象の理解
No full textレーザー加工は様々な時空間スケールの非線形現象が関連する複雑な過程である。そのため学理としての発展が進みずらい傾向にあった。本研究ではまずモデル構築を行い実験結果を解析することで加工が化学的過程であることを明らかとした。この結果から吸収エネルギーが分かれば加工に至るかを判別することが可能となった。そこで、第一原理計算による高精度シミュレーションにより励起過程の詳細な物理を解析した。これらにより、レーザー加工の理解と高精度予測に向けた大きな進展をもたらす事ができた。Q-LEAPシンポジウムconference poste
In vivo multiplexed analysis of aminopeptidase activities by hyperpolarized molecular probes for tumor diagnostic applications
No full textAminopeptidases (APs) in the renin-angiotensin system (RAS) and their activity balance play a crucial role in regulating vascular functions. Multiplexed analysis of RAS-related AP activities is useful for diagnosing diseases, including cancer. Dynamic nuclear polarization coupled magnetic resonance imaging (DNP-MRI) enables simultaneous detection of multiple enzymatic activities in vivo. However, developing practical DNP-MRI probes, especially for multiplexed detection, remains challenging. Here, we report the design of DNP-MRI probes for in vivo multiplexed analysis of AP activities. By integrating quantum mechanical calculations, organic synthesis, and physicochemical/biochemical evaluations, we developed a series of AP-responsive DNP-MRI probes with high enzymatic reactivities and distinguishable chemical shifts. Using these probes, we successfully detected and visualized multiple AP activities in vivo. Furthermore, we performed in vivo multiplexed analysis of RAS-related AP activities in tumor-bearing mice, demonstrating the potential of this approach for monitoring the efficacy of anti-angiogenic cancer therapy and for accurate discrimination of tumor types.journal articl
Ion Concentration and Voltage Imaging with Fluorescent Nanodiamonds
No full textThe nitrogen-vacancy (NV) center in diamond exists in different charge states with distinct photoluminescence properties, which are sensitive to the nanoscale electrochemical environment. Hence, the NV charge state is emerging as a powerful all-optical platform for nanoscale sensing and imaging. Although significant progress has been made in engineering near-surface NV centers in bulk diamond, controlling the NV charge state in fluorescent nanodiamonds (FNDs) has proven challenging, limiting the sensitivity and reliability of FND-based charge state sensing. Here, we demonstrate reliable, reversible switching between the fluorescent NV0 and non-fluorescent NV+ charge states in sub-30 nm FNDs via surface oxidation and hydrogenation, respectively, for single particles and particle powder. In aqueous electrochemical cells, we demonstrate voltage and ion concentration imaging based on the NV charge state in self-assembled FND layers on transparent substrates. Applied voltages reliably modulate the FND PL with a sensitivity of up to 16 mV Hz−1/2. Importantly, FND PL is also modulated by local changes in salt concentration with a sensitivity of up to 1.8% per millimolar NaCl, enabling all-optical imaging of ion concentration gradients at the microscale. Our results represent a significant step toward realizing fast, stable, and scalable nanoscale charge- and voltage-imaging technologies with sub-micrometer spatial resolution.journal articl
Radiation testing of polymer materials with stable transparency for space applications as a protective layer over satellite photovoltaic panels
No full textA functional prototype of a radiation-resistant polymeric material was developed for use as a transparent protective shield in satellite systems. Based on a cycloaliphatic epoxy resin, the material maintains high optical clarity after exposure to ionizing radiation of various types up to 1000 Gy. It was selected from 5 candidates that were tested under various irradiation types, including gamma rays, electrons, protons, neutrons, helium and carbon ions. The results confirmed excellent optical stability, making this material suitable for long-term deployment in space missions, particularly as a protective layer over satellite photovoltaic panels.journal articl
固体飛跡検出器CR-39を用いたレーザー駆動準単色100 MeV超陽子線の同定
No full text高強度レーザーJ-KAREN-Pのアップグレード後の最初の実験において、マイクロメートルスケールの水素クラスターターゲットを用い、準単色100 MeVの陽子線加速を実現した。講演では、独自開発した固体飛跡検出器CR-39を用いたスタック型検出器を用いた準単色100 MeVの陽子線の同定手法について報告する。レーザー学会学術講演会第46回年次大会conference presentatio