National Institutes for Quantum and Radiological Science and Technology
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軟X線多層膜を付加し1～2keV領域で高回折効率を呈する平面結像型 不等間隔溝球面ラミナー型回折格子の開発
No full text1～2keV領域で高回折効率を呈する軟X線多層膜を付加した平面結像型不等間隔溝球面ラミナー型回折格子を前回報告[1]した設計に従い製作し，回折効率を評価したので報告する。刻線密度1/σを2400 本/mmと仮定した設計の結果，最適な溝構造は，溝深さhが2.65 nm，デュティ比a /σが0.46で，入射角 αは87.50°となった。SiO2基板上にラミナー型回折格子溝を刻線した表面上に不等周期のW/B4C多層膜を積層し，更にその上にAu膜を積層することとした。W層の膜厚, dHi, i = 1~6, は全て 2.6 nm, B4Cの膜厚 dLi，i = 1~4，は 3.0 nm, dL5 とdL6はそれぞれ10.3 nm, 4.7 nmである。また，最上層のAu膜の膜厚，dH7，は 4.0 nm である。この膜構造により，低エネルギー光は最上層のAu膜で, 高エネルギー光は多層膜で主に回折されることになる。発表では放射光を用いて測定した回折効率と計算で得た回折効率のエネルギー依存性の比較を示す。その結果から製作した多層膜回折格子の dH7の値が設計値より1 nm 強厚いため、低エネルギー側で効率が比較的高く、高エネルギー側で低下していると考えられる。公益社団法人応用物理学会 2025年（令和7年）秋季学術講演会conference presentatio
Low-lying dipole transitions of 178,180Hf and 182,184,186W isotopes
No full textNuclear resonance fluorescence (NRF) measurements on natural Hf and natural W were performed using linearly polarized quasi-monochromatic gamma-ray beams generated by laser Compton scattering (LCS) at the high intensity gamma-ray source (HIgS) facility of Duke University. The gamma-ray beams, in the 2.4-3.2 MeV energy range, excited multiple nuclides simultaneously via NRF. In total, we observe 29 dipole transitions. The spin and parity of the observed levels can be determined from the intensity ratio of gamma-rays scattered parallel to the polarization plane of the incident gamma-rays and perpendicular to the polarization plane of the incident gamma-rays. The resonance widths as well as the spin-parity of these levels were determined. In this presentation, we report the experimental results of the magnetic dipole strength for the investigated isotopes.日本原子力学会 2025年秋の大会conference presentatio
中空ファイバーを用いた二段階パルス圧縮による高強度広帯域マルチテラヘルツ光の発生
No full text本研究では、これまでパルス圧縮に用いてきたマルチプレートブロードニング[4]より高いスループットが期待できる中空ファイバーを用いて、パルス圧縮と高強度マルチテラヘルツパルス発生を行った。第86回応用物理学会秋季学術講演会conference presentatio
Study of medical RI generation using laser-driven neutrons
No full textAdvances of the laser physics provided generation of high-flux short duration neutron pulses. We have generated neutron pulses using LFEX laser at Osaka University. We have discussed the possibility of generation of medical RI through nuclear reactions using laser-driven neutrons.光・量子ビーム科学合同シンポジウム2025（OPTO2025）conference poste
α 線がん治療薬の化学形・放射能同時分析システム
No full textα 線を利用したがん新療法の実用化には、半減期が数時間から数日と短い α 線放出核種を無駄に損失することなく、その化学形と放射能を迅速に分析する技術が不可欠である。本研究ではこうした短寿命 α 線放出核種の化学形と放射能を短時間で同時に分析可能な技術の確立を目的とし、化学分析手法の一つである薄膜クロマトグラフィを試料として用いた高感度 α 線分析システムを開発して製品化に至った。本講演では、開発したシステムのハードウェア及びソフトウェア両面における特長に加え、新療法の候補核種である 211At を用いた性能検証結果について紹介した。第65回日本核医学会学術総会conference presentatio
Spatial polarization distribution measurements of gamma rays produced by inverse Compton scattering
No full textHighly polarized MeV gamma rays, produced by laser Compton scattering (LCS) of a polarized laser with an electron beam, offer a unique probe for basic and applied physics research. As the polarization characteristics of these gamma rays vary with the position of the beam cross section, it is essential to understand the polarization properties when using polarized gamma rays. However, detailed measurements of the two-dimensional spatial polarization distribution have not yet been conducted. In the UVSOR synchrotron facility, a polarimeter was developed to measure the spatial polarization distribution of linearly polarized gamma rays. The polarimeter is based on asymmetry measurements of the Compton scattering cross section. The LCS gamma rays are irradiated onto an iron target, and the azimuthal intensity distribution of the Compton scattered gamma rays is measured by seven NaI detectors to determine the polarization axis. Moreover, the spatial polarization distribution of the LCS gamma rays can be measured by scanning a 1-mm diameter collimator in two dimensions. In this conference, we will report on measurement results of the spatial polarization distribution of linearly and circularly polarized LCS gamma-rays. The polarization axis of the polarized gamma rays was clearly measured to vary with scattering and azimuth angle. In the near future, we plan to use the developed polarimeter to also measure the spatial polarization distribution of gamma rays generated by an axially symmetric polarized laser.the 16th international particle accelerator conference (IPAC’25)conference poste
The relationship between hysteresis effect and visual discriminability and agreeableness
No full textThe Bayesian brain framework has been proposed as a new interpretation of placebo/nocebo effect. According to the framework, the placebo/nocebo effect are regarded as a result of active inference process for decreasing prediction error. A similar process i s observed in perception of ambiguous visual stimuli, and the hysteresis effect is one of the examples of the process. As the hysteresis effect is a representative effect that the prior knowledge impact on present perception, a deep understanding of the h ysteresis effect may contribute to the unraveling of the placebo/nocebo effect. However, precise research about the effect of hysteresis effect on perception has scarcely been explored. Moreover, it has been reported that individual differences in the degr ee of utilization prior knowledge to ambiguous visual stimuli, any research about the relationship between the individual personality and hysteresis effect have not been done. We aimed to clarify the relationship between the hysteresis effect and visual pe rception with signal detection theory and personality traits using the Big five inventory (FFI, NEO FFI).Ninety two healthy subjects underwent a visual hysteresis task and NEO FFI questionnaire online. The perceptual sensitivity increased, and the criterion decreased through the hysteresis task. The significant correlation between agreeableness from NEO FFI a nd hysteresis effect was observed. Our results suggested that people with high agreeableness tend to make greater use of prior knowledge,and further investigation of this field may be helpful in improving the accuracy of prediction of placebo responder.5th International Conference of the Society for Interdisciplinary Placebo Studies (SIPS)conference poste
最局在ワニエ関数に基づいた 第一原理ファンデルワールス補正の再考III
No full text第79回年次大会に引き続き、第一原理分子動力学シミュレーションにより最局在ワニエ関数に基づいたvan der Waals補正の改良を試みた結果について報告する。日本物理学会第80回年次大会（2025年）conference presentatio
Spatial polarization distribution measurements of MeV gamma rays produced by inverse Compton scattering
No full textPolarization measurements are essential in astrophysics and nuclear physics, offering profound insights into fundamental physical processes. In astrophysics, the polarization of gamma rays provides critical information about high-energy astrophysical phenomena such as black holes, neutron stars, and gamma-ray bursts, helping to explore the radiation mechanisms and the structure of the universe. The development of polarimeters with high sensitivity in the MeV region has been proposed, and it is expected that these detectors will be flown in space in the future. Highly polarized MeV gamma rays can be generated in the laboratory by inverse Compton scattering (ICS) of a polarized laser with an electron beam. ICS gamma rays possess characteristics such as energy tunable, quasi-monochromatic, and a low divergence angle (<1 mrad). Therefore, ICS gamma rays are ideal as a light source for measurements of directional sensitivity, polarization, and energy for astronomical gamma-ray detectors. In UVSOR synchrotron facility, 6.6 MeV gamma rays can be generated by a 90-degree collisional ICS between a 750 MeV electron beam and an 800 nm laser. The gamma rays are used for user applications such as positron annihilation spectroscopy and evaluation of gamma-ray detectors. As the electron beam energy, laser wavelength and laser injection angle are fixed, it is necessary to use gamma rays with different divergence angles to change the ICS gamma-ray energy. Specifically, the gamma-ray energy can be changed from 3 to 6.6 MeV by placing a lead collimator on the beam axis of the gamma rays and scanning its position. As the polarization characteristics of ICS gamma rays vary with the position of the beam cross section, understanding their spatial polarization distribution is important for gamma-ray applications, including the evaluation of astronomical gamma-ray detectors. However, detailed two-dimensional measurements of this distribution have not yet been conducted. To address this, a polarimeter was developed at UVSOR, enabling precise measurement of the spatial polarization distribution of MeV polarized gamma rays. The polarimeter is based on asymmetry measurements of the Compton scattering cross section. The ICS gamma rays are irradiated onto an iron target, and the azimuthal intensity distribution of the Compton scattered gamma rays is measured by seven NaI detectors to determine the polarization axis. Moreover, the spatial polarization distribution of the ICS gamma rays can be measured by scanning a 1-mm diameter collimator in two dimensions. In this conference, we will report on measurement results of the spatial polarization distribution of linearly and circularly polarized ICS gamma-rays. The polarization axis of the polarized gamma rays was clearly measured to vary with scattering and azimuth angle. We use the developed polarimeter to also measure the spatial polarization distribution of gamma rays generated by an axially symmetric polarized laser.The 39th International Cosmic Ray Conference (ICRC 2025)conference poste
Energy tunable polarized MeV gamma-ray sources at UVSOR
No full textIn gamma-ray astronomy, detectors with high sensitivity in the MeV region, which has not yet been explored, is expected to be flown in space in the future. In UVSOR synchrotron facility a MeV gamma-ray pulse source based on inverse Compton scattering (ICS) has been developed for user applications such as positron annihilation spectroscopy and gamma-ray detector evaluation. The ICS gamma rays possess other characteristics such as quasi-monochromatic (dE/E = a few %), highly polarized (~100%), and low divergence angle (<1 mrad). Linearly polarized gamma rays are generated by scattering of a linearly polarized laser and electron beam, and their polarization axis can be tuned to any angle by changing the angle of a half waveplate. Moreover, circularly polarized gamma rays can be generated using a circularly polarized laser, and their helicity can be easily inverted. The highly polarized and energy tunable gamma-ray sources are ideal as a light source for measurements of directional sensitivity, polarization, and energy for astronomical gamma-ray detectors. In this conference, details of the UVSOR’s gamma-ray source, including energy tunability, energy spread, and polarization characteristics, will be presented. The most basic polarization property of ICS gamma rays is that the polarization of linearly and circularly polarized gamma rays varies with the position of the beam cross section. The results of polarization measurements using a Compton polarimeter are described. In addition, the spatial intensity distribution and polarization characteristics of gamma rays generated by lasers with axially symmetric polarization states such as radial and azimuthal polarization, which have not been investigated theoretically or experimentally, will also be presented.The 39th International Cosmic Ray Conference (ICRC 2025)conference presentatio