Development of high-resolution imaging camera for alpha dust (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2020-039, 59 Pages, 2021/01

JAEA-Review-2020-039.pdf:4.18MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2019. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of high-resolution imaging camera for alpha dust" conducted in FY2019. We have developed an imaging camera with a position resolution of less than approximately 10 m to monitor alpha dust in the nuclear plant during the decommissioning process, because the operators avoid to drawing in such dusts. Moreover, we have developed real-time monitor system with optical fiber and scintillator under high dose-rate condition.

Development of imaging system with ultra-high spatial resolution aiming to detect alpha-dust (Contract research); FY2018 Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2019-038, 57 Pages, 2020/03

JAEA-Review-2019-038.pdf:4.6MB

JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. Among the adopted proposals in FY2018, this report summarizes the research results of the "Development of Imaging System with Ultra-high Spatial Resolution Aiming to Detect Alpha-dust". In the present study, we have developed a prototype of a system aiming to elucidate the behavior of alpha-dust generated at the time of debris retrieval. In this system, alpha-ray is first converted to visible light by novel scintillator. Then, imaging with ultra-high resolution will be possible using a lens and an Si-semiconductor camera (CMOS camera). Also, it will be possible to identify the species of alpha-ray emitting nuclides by unfolding of the spectra. The demonstration tests of the system will be conducted for dust samplers at the Plutonium Fuel Development Center, JAEA. In the development of the present system, it is important to use scintillator whose emission wavelength is sensitive to the CMOS camera as well as high emission scintillator. Considering these conditions, the key technology will be the improvement of the purity of crystals and optimization of the shapes of the materials including powers.

Large ferroquadrupole moment induced in the octupole-ordered CeLaB revealed by high-resolution X-ray diffraction

Inami, Toshiya; Michimura, Shinji*; Hayashi, Yuya*; Matsumura, Takeshi*; Sera, Masafumi*; Iga, Fumitoshi*

Physical Review B, 90(4), p.041108_1 - 041108_5, 2014/07

https://doi.org/10.1103/PhysRevB.90.041108

We carried out a high-resolution X-ray diffraction experiment on CeLaB. This compound exhibits antiferro-octupole order (AFO) below = 1.4 K, and it is theoretically suggested that ferroquadrupole moments and a resultant rhombohedral deformation are induced in the AFO phase. We observe the splitting of Bragg reflections below and find that the unit cell is rhombohedral with the elongated [111] axis. We also precisely evaluate the magnitude of the induced quadrupole moments from the obtained shear strain and find that the quadrupole moments are not reduced in the AFO phase.

High-pressure induced structural changes in metastable GeSbTe thin films; An X-ray absorption study

Fons, P.*; Kolobov, A.*; Tominaga, Junji*; Katayama, Yoshinori

Nuclear Instruments and Methods in Physics Research B, 238(1-4), p.160 - 162, 2005/08

https://doi.org/10.1016/j.nimb.2005.06.039

Super-resolution (SR) media offer up to a factor of ten increase in areal storage density over conventional DVD media. Although SR has been realized, there is a strong need for a deeper understanding of structural and electronic changes in GeSbTe (GST), a principal optical memory component, with external perturbations. Recording of SR disks leads to the formation of gas-phase bubbles that in turn lead to the development of large stresses on the underlying GST layer. In this paper we report on XAFS of nominally hydrostatic (0-10 GPa) compressive stress-induced structural changes of the metastable crystalline phase of GST. An analysis showed that the initial splitting of Ge Te bond lengths of the room-temperature distorted rocksalt structure decreased to a small but finite splitting for 6 GPa. The implications of this upon the proposed ferroelectric catastrophe super-RENS readout mechanism are discussed.

Development of ZnS/LiF scintillating and MSGC neutron detectors in JAERI

Nakamura, Tatsuya; Katagiri, Masaki; Yamagishi, Hideshi; Tanaka, Hiroki; Sakasai, Kaoru; Soyama, Kazuhiko

Hamon, 15(1), p.67 - 73, 2005/01

https://doi.org/10.5611/hamon.15.67

Development of scintillating and gaseous neutron detectors in Japan Atomic Energy Research Institute is briefly described. In this paper, the performances of the developed 2-d neutron detectors, concerning ZnS/LiF scintillating detectors with wavelength shifting fiber read-out and micro-strip gas chambers with individual read-out, are presented.

A Neutron crystallographic analysis of a rubredoxin mutant at 1.6 resolution

Chatake, Toshiyuki*; Kurihara, Kazuo; Tanaka, Ichiro*; Tsyba, I.*; Bau, R.*; Jenney, F. E. Jr.*; Adams, M. W. W.*; Niimura, Nobuo

Acta Crystallographica Section D, 60(8), p.1364 - 1373, 2004/08

https://doi.org/10.1107/S090744490401176X

A neutron diffraction study has been carried out at 1.6 resolution on a mutant rubredoxin from using the BIX-3 single-crystal diffractometer at the JRR-3 reactor of JAERI. In order to study the unusual thermostability of rubredoxin from , the hydrogen-bonding patterns were compared between the native and a 'triple-mutant' variant where three residues were changed so that they are identical to those in a mesophilic rubredoxin. In the present study, some minor changes were found between the wild-type and mutant proteins in the hydrogen-bonding patterns of the Trp3/Tyr3 region. The H/D-exchange ratios in the protein were also studied. The results suggest that the backbone amide bonds near the four Cys residues of the FeS redox center are most resistant to H/D exchange. In addition, the 1.6 resolution of the present neutron structure determination has revealed a more detailed picture than previously available of some portions of the water structure, including ordered and disordered O-D bonds.

Neutron crystallographic study on rubredoxin from by BIX-3, a single-crystal diffractometer for biomacromolecules

Kurihara, Kazuo; Tanaka, Ichiro*; Chatake, Toshiyuki*; Adams, M. W. W.*; Jenney, F. E. Jr.*; Moiseeva, N.*; Bau, R.*; Niimura, Nobuo

Proceedings of the National Academy of Sciences of the United States of America, 101(31), p.11215 - 11220, 2004/08

https://doi.org/10.1073/pnas.0403807101

The structure of a rubredoxin (Rd) from , an organism that grows optimally at 100 C, was determined using the neutron single-crystal diffractometer for biological macromolecules (BIX-3) at the JRR-3 reactor of JAERI. Data were collected at room temperature up to a resolution of 1.5 , and the completeness of the data set was 81.9 %. The model contains 306 H atoms and 50 D atoms. A total of 37 hydration water molecules were identified. The model has been refined to final agreement factors of = 18.6 % and = 21.7 %. Several orientations of the O-D bonds of side chains, whose assignments from X-ray data were previously ambiguous, were clearly visible in the neutron structure. While most backbone N-H bonds had undergone some degree of H/D exchange throughout the molecule, five H atom positions still had distinctly negative (H) peaks. The neutron Fourier maps clearly showed the details of an extensive set of H bonds involving the ND terminus that may contribute to the unusual thermostability of this molecule.

Neutron detection by superconducting tunnel junctions on a LiBO single-crystal absorber

Nakamura, Tatsuya; Katagiri, Masaki; Ukibe, Masahiro*; Ikeuchi, Takashi*; Okubo, Masataka*

Nuclear Instruments and Methods in Physics Research A, 520(1-3), p.67 - 69, 2004/03

https://doi.org/10.1016/j.nima.2003.11.222

We succeeded in detecting neutrons using superconducting tunnel junctions (STJs) fabricated on a single crystal of LiBO. Neutrons are captured in the crystal by the nuclear reactions Li + n T+ + 4.78 MeV and B + n Li + + 2.3 MeV, and generated phonons propagate in the absorber and are measured by the STJs. We selected a single crystal of LiBO as the absorber material because of properties such as the large neutron cross-section of Li and B, low -ray sensitivity, short particle range in the substrate, and fast phonon velocity. Series-connected or multiple STJs on the crystal would enable two-dimensional neutron imaging with high detection efficiency, low gamma-ray background, and a high spatial resolution of a few microns. We demonstrate neutron detection by the STJs and show their X-ray response and neutron detection. The correlation in pulse heights between two junctions located 1.3mm apart clearly indicates the possibility of neutron imaging.

Design and characteristics of the JRR-3M thermal neutron radiography facility and its imaging systems

Matsubayashi, Masahito; Kobayashi, Hisao*; Hibiki, Takashi*; Mishima, Kaichiro*

Nuclear Technology, 132(2), p.309 - 324, 2000/11

https://doi.org/10.13182/NT00-A3146

no abstracts in English

Development of a high-frame-rate neutron radiography system in JRR-3M

Matsubayashi, Masahito; Hibiki, Takashi*; Mishima, Kaichiro*

Proceedings of 6th World Conference on Neutron Radiography (WCNR6), p.261 - 268, 1999/00

no abstracts in English