International network of nuclear structure and decay data evaluators

Dimitriou, P.*; Basunia, S*; Bernstein, L.*; Chen, J.*; Elekes, Z.*; Huang, X.*; Hurst, A.*; Iimura, Hideki; Jain, A. K.*; Kelley, J.*; et al.

EPJ Web of Conferences, 239, p.15004_1 - 15004_4, 2020/09

BB2020-0008.pdf:0.34MB

https://doi.org/10.1051/epjconf/202023915004

The Evaluated Nuclear Structure Data File (ENSDF) includes the most extensive and comprehensive set of nuclear structure and decay data evaluations performed by the international network of Nuclear Structure and Decay Data evaluators (NSDD) under the auspices of the IAEA. In this report we describe some of the recent NSDD activities and provide future perspectives.

Cutting-edge studies on nuclear data for continuous and emerging need, 4; Nuclear chart; Magnificent landscape of nuclei

Koura, Hiroyuki; Minato, Futoshi; Iimura, Hideki

Nihon Genshiryoku Gakkai-Shi ATOMO, 60(1), p.35 - 40, 2018/01

no abstracts in English

Laser ablation absorption spectroscopy for isotopic analysis of plutonium; Spectroscopic properties and analytical performance

Miyabe, Masabumi; Oba, Masaki; Jung, K.; Iimura, Hideki; Akaoka, Katsuaki; Kato, Masaaki; Otobe, Haruyoshi; Khumaeni, A.*; Wakaida, Ikuo

Spectrochimica Acta, Part B, 134, p.42 - 51, 2017/08

https://doi.org/10.1016/j.sab.2017.05.008

Spectroscopic properties of atomic species of plutonium were investigated by combining laser ablation and resonance absorption techniques for the analysis of a plutonium oxide sample. For 17 transitions of Pu atoms and ions, the absorbance, isotope shift, and hyperfine splitting were determined via Voigt profile fitting of the recorded absorption spectra. Three transitions were selected as candidates for analytical use. Using these transitions, we investigated the analytical performance that was attainable and determined a correlation coefficient R2 between the absorbance and plutonium concentration of 0.9999, a limit of detection of 30-130 ppm, and a relative standard deviation of approximately 6% for an abundance of Pu of 2.4%. These results demonstrate that laser ablation absorption spectroscopy is applicable to the remote isotopic analysis of highly radioactive nuclear fuels and waste materials containing multiple actinide elements.

Ablation plume structure and dynamics in ambient gas observed by laser-induced fluorescence imaging spectroscopy

Miyabe, Masabumi; Oba, Masaki; Iimura, Hideki; Akaoka, Katsuaki; Khumaeni, A.*; Kato, Masaaki; Wakaida, Ikuo

Spectrochimica Acta, Part B, 110, p.101 - 117, 2015/08

AA2015-0183.pdf:3.11MB

https://doi.org/10.1016/j.sab.2015.06.004

The dynamic behavior of an ablation plume in ambient gas has been investigated by laser-induced fluorescence imaging spectroscopy. The second harmonic beam from an Nd:YAG laser (0.5-6J/cm) was focused on a sintered oxide pellet or a metal chip of gadolinium. The produced plume was subsequently intersected with a sheet-shaped UV beam from a dye laser so that time-resolved fluorescence images were acquired with an intensified CCD camera at various delay times. The obtained cross-sectional images of the plume indicate that the ablated ground state atoms and ions of gadolinium accumulate in a hemispherical contact layer between the plume and the ambient gas, and a cavity containing a smaller density of ablated species is formed near the center of the plume. At earlier expansion stage, another luminous component also expands in the cavity so that it coalesces into the hemispherical layer. The splitting and coalescence for atomic plume occur later than those for ionic plume. Furthermore, the hemispherical layer of neutral atoms appears later than that of ions; however, the locations of the layers are nearly identical. This coincidence of the appearance locations of the layers strongly suggests that the neutral atoms in the hemispherical layer are produced as a consequence of three-body recombination of ions through collisions with gas atoms. The obtained knowledge regarding plume expansion dynamics and detailed plume structure is useful for optimizing the experimental conditions for ablation-based spectroscopic analysis.

Development of NRD, 3; Study of a new moderator for compact 14-MeV pulsed neutron sources

Takamine, Jun; Koizumi, Mitsuo; Kureta, Masatoshi; Harada, Hideo; Kitatani, Fumito; Tsuchiya, Harufumi; Seya, Michio; Iimura, Hideki

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-35-Kai Nenji Taikai Rombunshu (Internet), 10 Pages, 2015/01

A prototype device of neutron resonance densitometry (NRD) with a D-T neutron generator was planned for basic studies of actual NRD devices. D-T neutron generators had features of simple handling and compact compared with photo neutron sources driven by electron beam accelerators. But those of D-T neutron are higher energy and lower intensity than those of photo neutron. We designed a new type moderator to compensate for the shortcomings. In the new type moderator, the D-T neutron generator is surrounded by Lead, and Polyethylene is arranged in the beam direction on the surface of Lead. As the result of analysis using Monte Carlo code MCNP5, it was found that the new moderator achieved about four times larger production of low energy neutrons than polyethylene moderator without distorting the energy resolution below at least 100 eV. The lead part in the new moderator are changed to other heavy metals, which is Uranium, and Tungsten. Analysis like the above were performed. We report these results.

Development of NRD, 1; Developments of a LaBr scintillation detector system for neutron resonance densitometry

Koizumi, Mitsuo; Tsuchiya, Harufumi; Kitatani, Fumito; Harada, Hideo; Takamine, Jun; Kureta, Masatoshi; Seya, Michio; Kimura, Atsushi; Iimura, Hideki; Becker, B.*; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-35-Kai Nenji Taikai Rombunshu (Internet), 8 Pages, 2015/01

We have proposed neutron resonance densitometry (NRD) as a method to quantify special nuclear materials in particle-like debris of melted fuel. NRD is a combination of neutron resonance transmission analysis (NRTA), and neutron resonance capture analysis (NRCA) (and prompt -ray analysis (PGA)). NRCA/PGA is used to identify contaminant elements, which is difficult to be detected by NRTA. To observe rays emitted in neutron capture reaction, a spectrometer consisting of LaBr scintillation detectors has been constructed. A newly installed data acquisition system enables us to measure 500 k event/s for each 8-channel inputs. In this presentation, the research and development of NRD is introduced and the status of the development of the spectrometer system is given as well.

Impact of systematic effects on results of neutron resonance transmission analysis

Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Takamine, Jun; Kureta, Masatoshi; Iimura, Hideki; Kimura, Atsushi; Becker, B.*; Kopecky, S.*; et al.

Nuclear Instruments and Methods in Physics Research A, 767, p.364 - 371, 2014/12

https://doi.org/10.1016/j.nima.2014.09.009

The impact of systematic effects on the areal density derived from a neutron resonance transmission analysis (NRTA) is investigated by measurements at the time-of-flight facility GELINA. The experiments were carried out at a 25 m station using metallic natural Cu discs with different thicknesses. To derive the areal density from a fit to the experimental transmission, the resonance shape analysis code REFIT was used. Large bias effects were observed using recommended resonance parameters. Therefore, neutron resonance parameters, in particular resonance energies and neutron widths, were derived from the transmission data obtained with a 0.25 mm thick Cu metallic sample. These parameters were used to study the impact of the resonance strength and sample thickness, on the accuracy of the areal density derived by NRTA.

Developments of a LaBr scintillation detector system for neutron resonance densitometry (NRD)

Koizumi, Mitsuo; Tsuchiya, Harufumi; Kitatani, Fumito; Harada, Hideo; Takamine, Jun; Kureta, Masatoshi; Seya, Michio; Kimura, Atsushi; Iimura, Hideki; Becker, B.*; et al.

Proceedings of INMM 55th Annual Meeting (Internet), 7 Pages, 2014/07

Neutron resonance densitometry for particle-like debris of melted fuel

Harada, Hideo; Kitatani, Fumito; Koizumi, Mitsuo; Takamine, Jun; Kureta, Masatoshi; Tsuchiya, Harufumi; Iimura, Hideki; Seya, Michio; Becker, B.*; Kopecky, S.*; et al.

Nuclear Data Sheets, 118, p.502 - 504, 2014/04

https://doi.org/10.1016/j.nds.2014.04.118

GEANT4 simulation study of a -ray detector for neutron resonance densitometry

Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Takamine, Jun; Kureta, Masatoshi; Iimura, Hideki

JAEA-Conf 2013-002, p.119 - 124, 2013/10

https://doi.org/10.11484/jaea-conf-2013-002

We have proposed a system to quantify nuclear materials in melted fuels in the reactors of the Fukushima Daiichi Nuclear Power Plant. The system utilizes non destructive techniques combining neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA). This is because the melted fuels are though to involve not only nuclear materials but also impurities such as Hydrogen, Boron, Zirconium, and Iron. Using the combined system, we would be able to identify those non-nuclear materials by NRCA and accurately measure nuclear materials by NRTA. A -ray detector for NRCA consists of a cylindrical LaBr scintillation counter and a well-type LaBr one. The well-type counter is served as a back-catcher detector and individual signals recorded in the two counters are summed to aim at reducing the Compton edge originating from Cs that generate intense background for the NRCA measurement. According to GEANT4 simulation, It can be seen that the Compton edge is suppressed by the well-type counter. For example, thanks to the well-type counter, a count at an energy of B-derived -rays (478 keV) is reduced by 0.15. In this presentation, we show performance of the -ray detector using GEANT4 simulation. In addition, comparing results based on evaluated cross sections of ENDF-VII.0 with those based on JENDL-4.0, we discuss differences in performance expected for the -ray detector.