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Suzuki, Daisuke; Kokubu, Yoko; Sakurai, Satoshi; Lee, C. G.; Magara, Masaaki; Iguchi, Kazunari*; Kimura, Takaumi
International Journal of Mass Spectrometry, 294(1), p.23 - 27, 2010/06
Times Cited Count：40 Percentile：87.1(Physics, Atomic, Molecular & Chemical)A new method for isotope ratio measurement with thermal ionization mass spectrometry (TIMS), "continuous heating method", was developed in order to determine an accurate isotope ratio of uranium ranging from sub-picograms to several dozen picograms. In this method, signals were measured during evaporation of an entire sample; however, part of the higher detected signals was used for calculation of the isotope ratio. The continuous heating method can measure the ratios with high reproducibility regardless of the sample amount and the skill of operators because procedures of measurement and data calculation were standardized, enabling accurate correction of mass discrimination effect. When 
U/
U ratios in isotopic reference materials measured by the continuous heating method were compared with those measured by the conventional method and the total evaporation method, there was no difference in the case of measurement of a larger amount of samples. However, the continuous heating method showed the most accurate result compared with those measured by the other methods for the measurement of the sample of sub-picograms.
Usuda, Shigekazu; Shinohara, Nobuo; Sakurai, Satoshi; Magara, Masaaki; Miyamoto, Yutaka; Esaka, Fumitaka; Yasuda, Kenichiro; Kokubu, Yoko; Hirayama, Fumio; Lee, C. G.; et al.
KEK Proceedings 2007-16, p.13 - 22, 2008/02
For the purpose of controlling and monitoring radiations and radioactive materials emitted from nuclear facilities to the environment and also evaluating their effects, various R&D on environmental radioactivity has been carried out at Japan Atomic Energy Agency (JAEA). Especially, for the abolition of nuclear weapons and for peaceful uses nuclear energy, ultra-trace analysis of environmental samples for safeguards and ultra-high sensitive monitoring of radionuclides for the CTBT verification, which have been scheduled in the middle of 1990s, have been promotted under the auspices of the Japanese Government at JAERI, the former of JAEA. In this presentation, the outline of R&D on environmental radioactivity for nuclear non-proliferation is introduced. In addition, applications of the developed techniques and future perspectives will be discussed.
Sakurai, Satoshi; Magara, Masaaki; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Inagawa, Jun; Suzuki, Daisuke; Iguchi, Kazunari; Kokubu, Yoko; et al.
STI/PUB/1298 (CD-ROM), p.791 - 799, 2007/08
no abstracts in English
Lee, C. G.; Iguchi, Kazunari; Inagawa, Jun; Suzuki, Daisuke; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Journal of Radioanalytical and Nuclear Chemistry, 272(2), p.299 - 302, 2007/05
Times Cited Count：47 Percentile：93.88(Chemistry, Analytical)no abstracts in English
Lee, C. G.; Iguchi, Kazunari; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu
Japanese Journal of Applied Physics, Part 2, 45(42), p.L1121 - L1123, 2006/11
Times Cited Count：4 Percentile：17.08(Physics, Applied)no abstracts in English
Usuda, Shigekazu; Yasuda, Kenichiro; Kokubu, Yoko; Esaka, Fumitaka; Lee, C. G.; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Hirayama, Fumio; Fukuyama, Hiroyasu; et al.
International Journal of Environmental Analytical Chemistry, 86(9), p.663 - 675, 2006/08
Times Cited Count：14 Percentile：40.18(Chemistry, Analytical)The IAEA introduced the environmental sample analysis method, as a powerful tool to detect undeclared nuclear activities, into strengthened safeguards system. The principle of the method is that nuclear signatures can be evidenced if trace amount of nuclear materials in environmental samples taken from inside and outside of nuclear facilities are accurately analyzed. Currently, isotope ratios of uranium and plutonium in "swipe" samples are measured, which are collected in nuclear facilities. In future, the subject of environmental sample analysis will expand to soil, sediment, vegetation, water and airborne dust taken from outside of the nuclear facilities. If physical and chemical form of the nuclear materials is identified, we may estimate their origin, treatment process and migration behavior. This paper deals with the developed analytical techniques for the safeguards environmental samples, the current R&D on techniques related to estimation of the physical and chemical form, and possible analytical methodologies applicable to ultra-trace amounts of nuclear materials.
Lee, C. G.; Iguchi, Kazunari; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Nuclear Instruments and Methods in Physics Research B, 245(2), p.440 - 444, 2006/04
Times Cited Count：8 Percentile：50.31(Instruments & Instrumentation)The etching rates of fission track detectors made of polycarbonate containing uranium particles were measured after thermal neutron irradiation with fluence of 8
10
n/cm
, in order to study the influence of uranium enrichment on the etching rate that was calculated from the weight loss by etching. There is a strong correlation between the etching rate of detector and the enrichment E of uranium particle: the former increases as the latter increases. Particularly, the etching rate per particle was proportional to E
rather than E
, which is probably due to the overlapping of fission tracks. The etching behaviors of detector revealed that the existence of two different etching rate regions, a nonlinear region in the beginning of etching process and a subsequent constant region, which was explained as the opening of fission tracks and the broadening of opened tracks, respectively.
Lee, C. G.; Iguchi, Kazunari; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Japanese Journal of Applied Physics, Part 2, 45(10), p.L294 - L296, 2006/03
Times Cited Count：18 Percentile：54.95(Physics, Applied)We have developed an effective method for fission track (FT) sample preparation to perform particle analysis of the safeguards environmental samples by the FT-thermal ionization mass spectrometry (TIMS) method. In this method, a fission track detector and the layer containing particles are separated. The main feature of the developed FT sample is that the detection of a particle from the corresponding fission track can be performed correctly and in a simple manner by fixing each one end of the detector and the particle layer and by using an etching tool. It is expected that this method will enhance the effectiveness of particle analysis.
Sakurai, Satoshi; Magara, Masaaki; Usuda, Shigekazu; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Inagawa, Jun; Suzuki, Daisuke; et al.
Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-27-Kai Nenji Taikai Rombunshu (CD-ROM), 9 Pages, 2006/00
no abstracts in English
Iguchi, Kazunari; Esaka, Konomi; Lee, C. G.; Inagawa, Jun; Esaka, Fumitaka; Onodera, Takashi; Fukuyama, Hiroyasu; Suzuki, Daisuke; Sakurai, Satoshi; Watanabe, Kazuo; et al.
Radiation Measurements, 40(2-6), p.363 - 366, 2005/11
Times Cited Count：11 Percentile：59.93(Nuclear Science & Technology)In particle analysis for safeguards environmental samples, the fission track technique is very important to detect sub-micrometer particles containing uranium. In the technique the authors developed, the particles were recovered onto the polycarbonate membrane filter. The filter was dissolved in solvent and dried to form a thin film of detector, in which the particles were confined. After thermal neutron irradiation and etching, the particles of interest in the detector were easily identified with fission tracks, and were picked up for isotope ratio analysis. It was found, however, that the particles in the vicinity of the detector surface may fall off during the etching process. Therefore, optimization of the etching condition is required. In this work, the effects of etching time and enrichment of uranium in particles were investigated. Preliminary results suggest that etching time should be shorter with the increase in the enrichment.
Sakurai, Satoshi; Magara, Masaaki; Usuda, Shigekazu; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Kono, Nobuaki; Inagawa, Jun; et al.
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
no abstracts in English
Iguchi, Kazunari
Nihon Shashin Gakkai-Shi, 68(1), p.56 - 59, 2005/02
In order to detect undeclared activities of nuclear facilities, Japan Atomic Energy Research Institute (JAERI) has developed analytical methods for safeguards environmental samples. As for particle analysis of safeguards environmental sample analysis which can determine isotope ratios of nuclear materials for individual particles, secondary ion mass spectrometry (SIMS) is known as a powerful method. However, it is difficult to analyze particles having diameter below 1 
m due to its detection limit. To overcome the problem, JAERI is developing an analytical method using fission track (FT) technique. The outline of the method is described in this report.
Magara, Masaaki; Usuda, Shigekazu; Sakurai, Satoshi; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Kono, Nobuaki; Inagawa, Jun; et al.
Dai-26-Kai Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Nenji Taikai Rombunshu, p.157 - 164, 2005/00
JAERI has conducted the analysis of domestic and the IAEA samples. JAERI is developing the analytical techniques to improve the analytical ability for the safeguards environmental samples. For bulk analysis, study is focused on the improvement of reliability of isotope ratio measurements by ICP-MS. New chemical separation techniques are under development and a desolvation module is introduced to reduce the polyatomic interferences. In particle analysis, the sample preparation procedure for SIMS method is modified to measure the 
U/U and 
U/U ratios for individual particles. We are also developing fission track-TIMS method to measure uranium isotope ratios in particles of sub-micrometer size. A screening instrument of X-ray fluorescent analysis is equipped to measure elemental distribution on a swipe surface.
Lee, C. G.; Iguchi, Kazunari; Inagawa, Jun; Suzuki, Daisuke; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Dai-26-Kai Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Nenji Taikai Rombunshu, p.171 - 178, 2005/00
Particle analysis by FT-TIMS method is effective for safeguards environmental samples because the isotope ratios of sub-micrometer particles can be determined. The FT-TIMS method developed by the authors, in which the particles are confined in the detector, has merits such as high detection efficiency and the possibility as a screening method for uranium particles according to their enrichment by controlling the etching time. However, it was found that a part of uranium particles contained in a detector may dissolve during the etching process of the detector. In order to overcome the problem, we are developing a novel sample preparing method in which the FT detector and the particle layer are separated. In the conventional FT sample of separated type, the detection process of particles of interest is time-consuming and complicated due to the discrepancy in position between tracks and particles. In contrast, the discrepancy was solved by fixing a part of a detector and a particle layer in our method, which improved the detection efficiency of particles containing fissile materials.
Magara, Masaaki; Usuda, Shigekazu; Sakurai, Satoshi; Watanabe, Kazuo; Esaka, Fumitaka; Hirayama, Fumio; Lee, C. G.; Yasuda, Kenichiro; Kono, Nobuaki; Inagawa, Jun; et al.
Proceedings of INMM 46th Annual Meeting (CD-ROM), 8 Pages, 2005/00
JAERI has been developing analytical techniques for ultra-trace amounts of nuclear materials in the environmental samples in order to contribute to the strengthened safeguards system. Development of essential techniques for bulk and particle analysis of the environmental swipe sample has been established as an ultra-trace analytical method of uranium and plutonium. In January 2003, JAERI was qualified as a member of the IAEA network analytical laboratories for environmental samples. Since then, JAERI has conducted the analysis of domestic and the IAEA samples. From Japanese fiscal year 2003, the second phase of the project was started for the development of advanced techniques, such as analyzing minor actinides and fission products as well as uranium and plutonium, particle analysis using fission-track technique, more efficient particle analysis using ICP-TOFMS and screening by X-ray fluorescent analysis. This paper deals with the progress in the development of the new techniques, applications and future perspective.
Lee, C. G.; Iguchi, Kazunari; Esaka, Konomi; Magara, Masaaki; Esaka, Fumitaka; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Analytica Chimica Acta, 517(1-2), p.215 - 220, 2004/07
Times Cited Count：4 Percentile：13.8(Chemistry, Analytical)In this study, we discussed the feasibility of solid sample ETV-ICP-MS for the particle analysis of the environmental swipe samples in order to establish the fission track-ETV-ICP-MS method. Samples used were solid samples containing Tl, Pb and U in polycarbonate film, and their standard solutions. The analytical performance will be reported in terms of the optimization of temperature program, and sensitivity and precision in isotope ratio measurement.
Esaka, Konomi; Esaka, Fumitaka; Inagawa, Jun; Iguchi, Kazunari; Lee, C. G.; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Japanese Journal of Applied Physics, Part 2, 43(7A), p.L915 - L916, 2004/07
Times Cited Count：41 Percentile：78.95(Physics, Applied)An effective method for isotope ratio analysis of individual particles containing uranium in safeguards swipe samples was developed by using a fission track (FT) technique combined with thermal ionization mass spectrometry (TIMS). The particles in the sample were directly recovered onto a polycarbonate membrane filter, which was set in a filtration system. After the particle recovery, the filter was dissolved to form a non-coated FT detector film containing the particles. Individual particles containing uranium were then identified by the observation of fission tracks created by thermal neutron irradiation. By combination of the FT technique with TIMS, isotope ratios of uranium for individual particles in the swipe sample prepared from a uranium standard reference material could be effectively determined.
Esaka, Fumitaka; Watanabe, Kazuo; Fukuyama, Hiroyasu; Onodera, Takashi; Esaka, Konomi; Inagawa, Jun; Iguchi, Kazunari; Suzuki, Daisuke; Lee, C. G.; Magara, Masaaki; et al.
Dai-25-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, p.128 - 135, 2004/00
Japan Atomic Energy Research Institute (JAERI) was qualified as a member of the IAEA network analytical laboratories (NWALs) for particle and bulk analyses of safeguards environmental samples in January 2003. The particle analysis gives more detailed information on nuclear facility operation than the bulk analysis because the isotope ratios of nuclear materials in the samples collected inside nuclear facilities (swipe samples) can be determined for individual particles. We applied, as a method for uranium isotope ratio measurement, secondary ion mass spectrometry (SIMS) to particle analysis. Prior to the SIMS analysis, the particles in a swipe sample are recovered onto a carrier by impaction. The carriers with the recovered particles are then screened by total reflection X-ray fluorescence spectrometry. We integrated these techniques into a standard procedure, which is applied to domestic and IAEA swipe samples routinely.
HT and T+TT
in 
He-
He quantum media under saturated vapor pressure at 1.6 KAratono, Yasuyuki; Iguchi, Kazunari; Okuno, Kenji*; Kumada, Takayuki
Journal of Physical Chemistry A, 107(19), p.3741 - 3746, 2003/05
Times Cited Count：4 Percentile：11.72(Chemistry, Physical)An influence of superfluidity on recombination reactions of H+THT, T+TT in He-He quantum media was studied under saturated vapor pressure at 1.6 K. A change of reaction mechanism was observed at transition point from normalfluid to superfluid phase. Tunneling reaction mechanism by H and T bubble atoms was proposed on the basis of large isotope effect.
Makuuchi, Keizo; Tagawa, Seiichi*; Kashiwagi, Masayuki*; Kamada, Toshimitsu*; Sekiguchi, Masayuki*; Hosobuchi, Kazunari*; Tominaga, Hiroshi*; Ooka, Norikazu
Journal of Nuclear Science and Technology, 39(9), p.1002 - 1007, 2002/09
Times Cited Count：6 Percentile：39.54(Nuclear Science & Technology)no abstracts in English
