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論文

$$^{241}$$Am neutron capture cross section measurement using the NaI(Tl) spectrometer of the ANNRI beamline of J-PARC

Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 児玉 有*; 中野 秀仁*; 佐藤 八起*

Journal of Nuclear Science and Technology, 61(4), p.459 - 477, 2024/04

 被引用回数:1 パーセンタイル:25.62(Nuclear Science & Technology)

The neutron capture cross-section of $$^{241}$$Am was measured from 10 meV to about 1 MeV using the NaI(Tl) spectrometer of the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline in the Materials and Life Science (MLF) facility of the Japan Proton Accelerator Research Complex (J-PARC). The total energy detection principle was applied in conjunction with the pulse-height weighting technique to derive the neutron capture yield. The present cross-section results were normalized using a $$^{197}$$Au sample measurement by applying the saturated resonance method. The thermal cross section was measured to be 708 $$pm$$ 22 b, in agreement within uncertainties to the present evaluation in JENDL-5 of 709 b. Moreover, the results of a shape resonance analysis of the resolved resonance region are also provided in the present dissertation.

論文

Measurements of the neutron capture cross section of Am-243 with the ANNRI beamline, MLF/J-PARC

児玉 有*; 片渕 竜也*; Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 中野 秀仁*; 佐藤 八起*; 堀 順一*; 芝原 雄司*; et al.

EPJ Web of Conferences, 284, p.01024_1 - 01024_3, 2023/05

 被引用回数:0 パーセンタイル:0.00(Nuclear Science & Technology)

The measurements were performed using the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline at the Japan Proton Accelerator Research Complex (J-PARC). An intense pulsed neutron beam was produced via spallation reaction in the mercury target of the Material and Life Science Experimental Facility by the 3-GeV proton beam of the J-PARC facility. A Time of Flight (TOF) method using a NaI(Tl) detector was employed in this measurements and a pulse-height weighting technique was used to derive a neutron capture yield. A sample of Am-243 with a mass of 38.14 mg (281.8 MBq) was used for the measurements. The neutron energy spectrum was obtained by using the 478 keV gamma-rays from the $$^{10}$$B(n,$$alpha$$)$$^{7}$$Li reaction with a boron sample. A preliminary value for the capture cross section of Am-243 will be presented in the contribution.

論文

Neutron capture cross section measurement and resonance analysis of $$^{107}$$Pd using ANNRI at MLF/J-PARC

中野 秀仁*; 片渕 竜也*; 寺田 和司*; 木村 敦; 中村 詔司; 遠藤 駿典; Rovira Leveroni, G.; 児玉 有*

EPJ Web of Conferences, 284, p.01032_1 - 01032_3, 2023/05

 被引用回数:0 パーセンタイル:0.00(Nuclear Science & Technology)

In the present work, the neutron capture cross section measurements were carried out using the Accurate Neutron Nucleus Reaction Measurement Instrument (ANNRI) at the Materials and Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). A high intensity pulsed neutron beam from Japan Spallation Neutron Source at the MLF using the 3 GeV proton beam was utilized. NaI(Tl) detectors of ANNRI were used for capture measurements. The time-of-flight (TOF) method was employed to determine the incident neutron energy. Two-dimensional data, TOF and pulse-height (PH), were acquired and the data were analyzed based on a PH weighting technique. Resonance parameters were derived from resonance analysis using the REFIT code.

論文

Neutron filtering system for neutron capture cross section measurement at the ANNRI beamline of MLF/J-PARC

Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 児玉 有*; 中野 秀仁*; 堀 順一*; et al.

EPJ Web of Conferences, 284, p.06007_1 - 06007_4, 2023/05

 被引用回数:0 パーセンタイル:0.00(Nuclear Science & Technology)

A neutron filtering system has been installed at the ANNRI beamline in order to bypass the doublet structure of the incident neutron beam in the keV region. Thick cylindrical slabs of $$^{nat}$$Fe, $$^{nat}$$Si and $$^{nat}$$Cr which share the characteristic of a sharp minimum in the neutron total cross section, were separately introduced in an intermediate stage of the beamline, before the NaI(Tl) spectrometer experimental area. The filtered neutron beams were analyzed by means of both neutron capture and transmission experiments. Moreover, further information about the neutron energy distribution within the filtered peaks was derived through the use of Monte-Carlo simulations with the PHITS code. The characteristics of the filtered neutron beams for $$^{nat}$$Fe, $$^{nat}$$i and $$^{nat}$$Cr are presented together with $$^{197}$$Au standard experimental results to assess the performance of the neutron filtering system in neutron capture cross section experiments.

論文

$$^{241}$$Am neutron capture cross section in the keV region using Si and Fe-filtered neutron beams

Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 児玉 有*; 中野 秀仁*

Journal of Nuclear Science and Technology, 60(5), p.489 - 499, 2023/05

 被引用回数:3 パーセンタイル:42.88(Nuclear Science & Technology)

The neutron capture cross-section of $$^{241}$$Am was measured in the keV neutron range using the recently implemented neutron filtering system of the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline in the Materials and Life Science (MLF) facility of the Japan Proton Accelerator Research Complex (J-PARC). Filter arrays consisting of 20 cm of $$^{nat}$$Fe and $$^{nat}$$Si were employed in separate measurements to provide filtered neutron beams with averaged neutron energies of 23.5 (Fe), 51.5 and 127.7 (Si) keV. The present $$^{241}$$Am results were obtained relative to the $$^{197}$$Au neutron capture yield by applying the total energy detection principle together with the pulse-height weighting technique. The $$^{241}$$Am neutron capture cross section was determined as 2.72 $$pm$$ 0.29 b at 23.5 keV, 2.14 $$pm$$ 0.26 b at 51.5 keV and 1.32 $$pm$$ 0.10 b at 127.7 keV with total uncertainties in the range of 8 to 12$$%$$, much lower in comparison to the latest time-of-flight experimental data available.

論文

Fast-neutron capture cross section data measurement of minor actinides for development of nuclear transmutation systems

片渕 竜也*; 岩本 修; 堀 順一*; 木村 敦; 岩本 信之; 中村 詔司; Rovira Leveroni, G.; 遠藤 駿典; 芝原 雄司*; 寺田 和司*; et al.

EPJ Web of Conferences, 281, p.00014_1 - 00014_4, 2023/03

Long-lived minor actinides (MA) in nuclear waste from nuclear power plants are a long-standing issue to continue nuclear energy production. To solve the issue, researchers have suggested nuclear transmutation, in which long-lived radionuclides are transmuted into stable or shorter-life nuclides via neutron-induced nuclear reactions. Development of nuclear transmutation systems as an accelerator-driven system requires accurate neutron nuclear reaction data. The present research project entitled "Study on accuracy improvement of fast-neutron capture reaction data of long-lived MAs for development of nuclear transmutation systems" have been conducted as a joint collaboration, including Tokyo Tech, Japan Atomic Energy Agency and Kyoto University. This project focuses on the neutron capture reaction of MAs, especially $$^{237}$$Np, $$^{241}$$Am and $$^{243}$$Am, in the fast neutron energy region. The final goal of this project is to improve the accuracies of the neutron capture cross sections of $$^{237}$$Np, $$^{241}$$Am and $$^{243}$$Am employing a high-intensity neutron beam from a spallation source of the Japan Proton Accelerator Research Complex (J-PARC) that reduces uncertainties of measurement. To achieve the goal, a neutron beam filter system in J-PARC, sample characteristic assay, and theoretical reaction model study were developed. In this contribution, the overview and results of the project will be presented.

論文

Development of a neutron beam monitor with a thin plastic scintillator for nuclear data measurement using spallation neutron source

中野 秀仁*; 片渕 竜也*; Rovira Leveroni, G.; 児玉 有*; 寺田 和司*; 木村 敦; 中村 詔司; 遠藤 駿典

Journal of Nuclear Science and Technology, 59(12), p.1499 - 1506, 2022/12

 被引用回数:2 パーセンタイル:29.47(Nuclear Science & Technology)

A neutron monitoring detection system was developed for neutron capture cross section measurement using a spallation neutron source. A combination of a plastic scintillator and a thin $$^{6}$$LiF foil was adopted for the detector. The detector system was tested to study the feasibility of the system. Neutron irradiation experiments were conducted with the Accurate Neutron-Nucleus Reaction Measurement Instrument in the Materials and Life Science facility of the Japan Proton Accelerator Research Complex. A neutron time-of-flight spectrum was successfully measured without significant count loss or detector paralysis. The statistical uncertainty reached 0.7% at neutron energies around 6 meV.

論文

$$^{241}$$Am neutron capture cross section measurement and resonance analysis

Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 児玉 有*; 中野 秀仁*; 佐藤 八起*

JAEA-Conf 2022-001, p.91 - 96, 2022/11

Neutron capture cross section measurements were performed in the Accurate Neutron Nucleus Reaction Measurement Instrument (ANNRI) at the Materials and Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). The time-of-flight (TOF) methodology was employed in a non-filter condition experiment to determine the neutron capture cross section from thermal to about 100 eV. Moreover, experiments were performed using the neutron filtering system to determine the neutron capture cross section at the energy of 23.5 keV using Fe as filter material. In this study, the preliminary results of the $$^{241}$$Am neutron capture cross section from 10 meV to about 100 eV determined in TOF experiments and at 23.5 keV from Fe filter experiments are presented. In the TOF experiments, the $$^{241}$$Am neutron capture cross section was normalized by means of the saturated resonance method using a Au sample with a mass of 1.5 g. In addition, for the Fe filter experiments, the capture cross section of $$^{241}$$Am at the energy of 23.5 keV was determined relative to the $$^{197}$$Au yield obtained from a measurement using the same Au sample. Moreover, early-stage results of a resonance analysis of the $$^{241}$$Am capture resonances are also presented.

論文

KeV-neutron capture cross-section measurement of $$^{197}$$Au with a Cr-filtered neutron beam at the ANNRI beamline of MLF/J-PARC

Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 児玉 有*; 中野 秀仁*; 佐藤 八起*; et al.

Journal of Nuclear Science and Technology, 59(5), p.647 - 655, 2022/05

 被引用回数:1 パーセンタイル:10.00(Nuclear Science & Technology)

Cr-filtered keV-neutron experiments were performed in the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline in the Materials and Life Science (MLF) facility of the Japan Proton Accelerator Research Complex (J-PARC) to measure the neutron capture cross-section of $$^{197}$$Au. The energy range of the neutron filtering system at ANNRI was extended through the use of 15 cm of $$^{nat}$$Cr as filter material to tailor quasi-monochromatic neutron peaks with averaged neutron energies of 133.4 and 45.0 keV. The performance of the $$^{nat}$$Cr filter assembly was evaluated by means of experimental capture and transmission analyses, together with the use of Monte-Carlo simulations. The present $$^{197}$$Au neutron capture cross-section results provide agreement within uncertainties with the JENDL-4.0 standard evaluated library and the IAEA standard data library further demonstrating the capabilities of the neutron filtering system at ANNRI.

論文

Development of a neutron beam monitor for nuclear data measurement using spallation neutron source

中野 秀仁*; 片渕 竜也*; Rovira Leveroni, G.*; 児玉 有*; 寺田 和司*; 木村 敦; 中村 詔司; 遠藤 駿典

JAEA-Conf 2021-001, p.166 - 170, 2022/03

In neutron capture cross section measurement, monitoring the number of the incident neutrons is necessary. However, in measurement with J-PARC/ANNRI, direct neutron monitoring system has not been employed. Conventional neutron detectors cannot be used as a beam monitor at ANNRI because of two reasons, high counting rate environment and gamma-flash. In general, a semiconductor detector or an inorganic scintillator, which is adopted for a neutron detector, has relatively longer response time and is unsuitable for beam monitoring at ANNRI. Therefore, a combination of a thin plastic scintillator and a $$^{6}$$LiF foil was selected as a detection system, whose fast response enabled detecting neutrons at a high counting rate. Low gamma ray sensitivity of a thin plastic scintillator allows measuring fast TOF region without count loss or detector paralysis. The geometry of the $$^{6}$$LiF foil, the plastic scintillator, and photomultiplier tube (PMT) was designed. The optimal thickness of the $$^{6}$$LiF foil was determined with simulation codes, SRIM and PHITS. The detector system was tested under the high neutron irradiation condition at J-PARC /ANNRI. A neutron TOF spectrum was successfully measured without significant count loss or detector paralysis. A neutron energy spectrum was driven from difference of TOF spectrum with and without $$^{6}$$LiF. The neutron spectrum was compared with a past neutron spectrum and good agreement was obtained. Statistic error was 0.68 $$%$$ at 6.0 meV even though measurement times in this study were short.

論文

A New method to reduce systematic uncertainties of capture cross section measurement using a sample rotation system

児玉 有*; 片渕 竜也*; Rovira Leveroni, G.; 中野 秀仁*; 寺田 和司*; 木村 敦; 中村 詔司; 遠藤 駿典

JAEA-Conf 2021-001, p.162 - 165, 2022/03

Precise nuclear data for neutron-induced reactions are necessary for the design of nuclear transmutation systems. Nevertheless, current uncertainties of nuclear data for minor actinide (MA) does not achieve requirements for the design of transmutation facilities. The determination of an incident neutron flux for measurements of neutron capture cross section is one of the main causes that affect the final uncertainty of the cross section results. In the present work, we suggest a new method to reduce systematic uncertainties of capture cross section measurements. The method employs change of the self-shielding effect with sample rotation angle. In capture cross section measurements in ANNRI, a boron sample is placed to determine the incident neutron spectrum by counting 478 keV $$gamma$$-ray from the $$^{10}B(n,alphagamma)^{7}Li$$ reaction. In this method, the boron sample is tilted with respect to the neutron beam direction, thereby changing the effective area. This results in change of the shapes of time-of-flight (TOF) spectrum of 478 keV $$gamma$$-ray from the $$^{10}B(n,alphagamma)^{7}Li$$ reaction with the tilted angle. Comparing the difference of the TOF spectra at different angles and assuming the 1/v energy dependence of cross section of the $$^{10}B(n,alphagamma)^{7}Li$$ reaction, the area density of the boron sample can be determined without using the sample mass and area. Theoretical and experimental studies on the new method are ongoing. Calculation using Monte Carlo simulation code PHITS were carried out to study the feasibility of the present method. Test experiments using a sample rotation system at ANNRI were also performed.

論文

Neutron filtering system for fast neutron cross-section measurement at ANNRI

Rovira Leveroni, G.; 岩本 修; 木村 敦; 中村 詔司; 岩本 信之; 遠藤 駿典; 片渕 竜也*; 寺田 和司*; 児玉 有*; 中野 秀仁*; et al.

JAEA-Conf 2021-001, p.156 - 161, 2022/03

A neutron filtering system has been designed in order to bypass the double-timed structure of the beam. Filter materials were introduced into the rotary collimator of the ANNRI beamline in order to produce quasi-monoenergetic neutron filtered beams. Filter assemblies consisting of Fe with a thickness of 20 cm, and Si with thicknesses of 20 cm and 30 cm of Si were used separately to produce filtered neutron peaks with energies of 24 keV (Fe) and of 54 and 144 (Si). In this study, the characteristics and performance of the neutron filtering system at ANNRI using Fe and Si determined from both measurements and simulations are presented. The incident neutron flux was tested and analyzed by means of transmission and capture experiments. Moreover, simulations using the PHITS code were performed in order to determine the energy distribution of the integrated filtered peaks and assess the reliability of experimental results. Finally, preliminary results of the capture cross section of $$^{197}$$Au at the filtered energies of 24, 54 and 144 keV are also presented using the NaI(Tl) spectrometer alongside the neutron filtering system.

論文

Measurements of the neutron capture cross section of $$^{243}$$Am around 23.5 keV

児玉 有*; 片渕 竜也*; Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 信之; 岩本 修; 堀 順一*; 芝原 雄司*; et al.

Journal of Nuclear Science and Technology, 58(11), p.1159 - 1164, 2021/11

 被引用回数:4 パーセンタイル:40.86(Nuclear Science & Technology)

The neutron capture cross section of $$^{243}$$Am was measured with a pulsed neutron beam from a spallation neutron source of the Japan Proton Accelerator Research Complex. A Fe neutron beam filter was used to make the incident neutron beam mono-energetic around 23.5 keV. The neutron capture $$gamma$$-rays were detected with a NaI(Tl) detector. The pulse height weighting technique was employed to derive the neutron capture cross section from the pulse height spectrum. The cross section was determined relative to the capture cross section of $$^{197}$$Au of JENDL-4.0. The neutron capture cross section of $$^{243}$$Am was determined with a smaller uncertainty than previous measurements. The previous measurements and the JENDL-4.0 cross sections were found to be lower than the present result.

論文

Neutron beam filter system for fast neutron cross-section measurement at the ANNRI beamline of MLF/J-PARC

Rovira Leveroni, G.; 木村 敦; 中村 詔司; 遠藤 駿典; 岩本 修; 岩本 信之; 片渕 竜也*; 寺田 和司*; 児玉 有*; 中野 秀仁*; et al.

Nuclear Instruments and Methods in Physics Research A, 1003, p.165318_1 - 165318_10, 2021/07

 被引用回数:5 パーセンタイル:51.80(Instruments & Instrumentation)

A neutron filtering system has been introduced in the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) beamline in the Material and Life Science (MLF) building of the Japan Proton Accelerator Research Complex (J-PARC) in order to produce quasi-monoenergetic neutron beams. The filtered neutron spectrum by the filter assemblies was analyzed by means of capture and transmission measurements and also by Monte Carlo simulations using PHITS. The characteristics of the filtered neutron beam are discussed alongside its viability in future applications for neutron cross-section measurements in the fast neutron region.

論文

Polarization analysis for small-angle neutron scattering with a $$^{3}$$He spin filter at a pulsed neutron source

奥平 琢也; 上田 祐生; 廣井 孝介; 元川 竜平; 稲村 泰弘; 高田 慎一; 奥 隆之; 鈴木 淳市*; 高橋 慎吾*; 遠藤 仁*; et al.

Journal of Applied Crystallography, 54(2), p.548 - 556, 2021/04

 被引用回数:5 パーセンタイル:51.49(Chemistry, Multidisciplinary)

$$^{3}$$Heスピンフィルタを中性子スピン解析子として使用することにより、パルス中性子源での中性子小角散乱実験において、偏極解析を行うことに成功した。本実験に使用した$$^{3}$$Heスピンフィルタは中性子小角散乱実験を行うために十分な立体角をカバーすることができ、$$^{3}$$He偏極緩和時間も数日と長く、これは実験を完遂するために十分な性能である。水素原子による非干渉性散乱は非常に大きく、試料の組成から計算によって非干渉性散乱量を見積もる試みが行われていたが、正確に非干渉性散乱量を決定することは難しかった。しかし本研究では試料内での中性子の多重散乱を考慮した偏極解析実験を行うことで、干渉性散乱と非干渉性散乱を正確に分離することが可能となった。現在までパルス中性子源での中性子小角散乱では、偏極解析の手法が確立されていなかったが、本成果によって、様々な種類の試料に対して干渉性散乱と非干渉性散乱を正確に分離することができるようになると予想される。

論文

Neutron capture cross section measurement of minor actinides in fast neutron energy region for study on nuclear transmutation system

片渕 竜也*; 堀 順一*; 岩本 信之; 岩本 修; 木村 敦; 中村 詔司; 芝原 雄司*; 寺田 和司*; 登坂 健一*; 遠藤 駿典; et al.

JAEA-Conf 2020-001, p.5 - 9, 2020/12

A research project entitled "Study on accuracy improvement of fast-neutron capture reaction data of long-lived MAs for development of nuclear transmutation systems" has been ongoing since 2017. The project aims at improving accuracy of neutron capture cross sections of long-lived minor actinides (MAs; $$^{237}$$Np and $$^{241,243}$$Am) in the fast neutron energy region which are very important for development of nuclear transmutation systems. In order to improve the capture reaction data of MAs, measurements using an intense pulsed neutron beam from a spallation neutron source of J-PARC are planned. The project consists of four parts: (1) development of neutron beam filter system, (2) cross section measurement, (3) sample characteristic assay, and (4) theoretical study. The filter system is designed to solve a double bunch issue in J-PARC. The sample characteristic assay lowers systematic uncertainties originating the samples. In the theoretical study, a nuclear reaction model is applied to analyzing cross sections and $$gamma$$-ray spectra measured in experiments. The outline of the project and the current progress will be presented.

論文

Development and application of a $$^3$$He neutron spin filter at J-PARC

奥平 琢也; 奥 隆之; 猪野 隆*; 林田 洋寿*; 吉良 弘*; 酒井 健二; 廣井 孝介; 高橋 慎吾*; 相澤 一也; 遠藤 仁*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

 被引用回数:20 パーセンタイル:89.09(Instruments & Instrumentation)

We are developing a neutron polarizer with polarized $$^3$$He gas, referred to as a $$^3$$He spin filter, based on the Spin Exchange Optical Pumping (SEOP) for polarized neutron scattering experiments at Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC). A $$^3$$He gas-filling station was constructed at J-PARC, and several $$^3$$He cells with long spin relaxation times have been fabricated using the gas-filling station. A laboratory has been prepared in the MLF beam hall for polarizing $$^3$$He cells, and compact pumping systems with laser powers of 30 W and 110 W, which can be installed onto a neutron beamline, have been developed. A $$^3$$He polarization of 85% was achieved at a neutron beamline by using the pumping system with the 110 W laser. Recently, the first user experiment utilizing the $$^3$$He spin filter was conducted, and there have been several more since then. The development and utilization of $$^3$$He spin filters at MLF of J-PARC are reported.

論文

Status of neutron spectrometers at J-PARC

梶本 亮一; 横尾 哲也*; 中村 充孝; 川北 至信; 松浦 直人*; 遠藤 仁*; 瀬戸 秀紀*; 伊藤 晋一*; 中島 健次; 河村 聖子

Physica B; Condensed Matter, 562, p.148 - 154, 2019/06

BB2018-0526.pdf:2.45MB

 被引用回数:17 パーセンタイル:58.46(Physics, Condensed Matter)

Seven time-of-flight quasielastic/inelastic neutron scattering instruments are installed on six beamlines in the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC). Four of these instruments are chopper-type direct-geometry spectrometers, one is a near-backscattering indirect-geometry spectrometer, and the other two are spin-echo-type spectrometers. This paper reviews the characteristic features, recent scientific outcomes, and progress in development of MLF spectrometers.

論文

A Telescoping view of solute architectures in a complex fluid system

元川 竜平; 小林 徹; 遠藤 仁; Mu, J.*; Williams, C. D.*; Masters, A. J.*; Antonio, M. R.*; Heller, W. T.*; 長尾 道弘*

ACS Central Science, 5(1), p.85 - 96, 2019/01

 被引用回数:56 パーセンタイル:86.16(Chemistry, Multidisciplinary)

We present a hierarchical aggregate model of an organic phase containing a coordination species that acts as a fundamental building unit of higher-order structures formed in the organic phase. We aimed to elucidate the fundamental aspects of the microscopic structure and phase separation occurring in ionic separation and recovery systems during solvent extraction. The coordination species aggregate through a hydrogen-bonding network formed by interaction between the hydrophilic part of the coordination species with extracted water and acid molecules. This reduces the hydrophilic surface area, resulting in subsequent formation of small primal clusters of 2 to 3 nm in diameter. The primal clusters further aggregate due to van der Waals interaction to form large aggregates of $$<$$ 10 nm in diameter. The size of the primal cluster does not depend on the concentration of the coordination species, whereas the size of the large aggregate increases as the aggregation number of the primal clusters increases. We conclude that hybrid interaction is a key driving force in the formation and growth of the hierarchical aggregate and the induction of phase separation of the organic phase.

論文

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

中島 健次; 川北 至信; 伊藤 晋一*; 阿部 淳*; 相澤 一也; 青木 裕之; 遠藤 仁*; 藤田 全基*; 舟越 賢一*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

J-PARC物質・生命科学実験施設の中性子実験装置についてのレビューである。物質・生命科学実験施設には23の中性子ビームポートがあり21台の装置が設置されている。それらは、J-PARCの高性能な中性子源と最新の技術を組み合わせた世界屈指の実験装置群である。このレビューでは、装置性能や典型的な成果等について概観する。

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