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Journal Articles

High-resolution Compton cameras based on Si/CdTe double-sided strip detectors

Odaka, Hirokazu*; Ichinohe, Yuto*; Takeda, Shinichiro*; Fukuyama, Taro*; Hagino, Koichi*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; Watanabe, Shin*; Kokubun, Motohide*; et al.

Nuclear Instruments and Methods in Physics Research A, 695, p.179 - 183, 2012/12

 Times Cited Count:19 Percentile:84.11(Instruments & Instrumentation)

We have developed a new Si/CdTe semiconductor double-sided strip detector (DSD) Compton camera. The camera consists of a 500-$$mu$$m-thick Si-DSD and four layers of 750-$$mu$$m-thick CdTe-DSDs all of which have common electrode configuration segmented into 128 strips on each side with pitches of 250$$mu$$m. In order to realize high angular resolution and to reduce size of the detector system, a stack of DSDs with short stack pitches of 4 mm is utilized to make the camera. Taking advantage of the excellent energy and position resolutions of the semiconductor devices, the camera achieves high angular resolutions of 4.5 degrees at 356 keV and 3.5 degrees at 662 keV. To obtain such high resolutions together with an acceptable detection efficiency, we demonstrate data reduction methods including energy calibration using Compton scattering continuum and depth sensing in the CdTe-DSD. We also discuss imaging capability of the camera and show simultaneous multi-energy imaging.

Journal Articles

Applications and imaging techniques of a Si/CdTe Compton $$gamma$$-ray camera

Takeda, Shinichiro*; Ichinohe, Yuto*; Hagino, Koichi*; Odaka, Hirokazu*; Yuasa, Takayuki*; Ishikawa, Shinnosuke*; Fukuyama, Taro*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; et al.

Physics Procedia, 37, p.859 - 866, 2012/10

 Times Cited Count:16 Percentile:98.04

By using new Compton camera consisting of silicon double-sided strip detector (Si-DSD) and CdTe-DSD developed for the ASTRO-H mission, an experiment was conducted to study its feasibility for advanced hotspot monitoring. In addition to hotspot imaging already provided by commercial imaging systems, the identification of the variety of radioisotopes is realized thanks to the good energy resolution given by the semiconductor detectors. Three radioisotopes of $$^{133}$$Ba (356 keV), $$^{22}$$Na (511 keV) and $$^{137}$$Cs (662 keV) were individually imaged by applying event selection in the energy window and the $$gamma$$-ray images was correctly overlapped by an optical picture. The detection efficiency of 1.68$$times$$10$$^{-4}$$ (effective area: 1.7$$times$$10$$^{-4}$$ cm$$^2$$) and angular resolution of 3.8$$^{circ}$$ were obtained by stacking five detector modules for 662 keV $$gamma$$-ray. The higher detection efficiency required in a specific use can be achieved by stacking more detector modules.

Journal Articles

Development of analytical technique for safeguards environmental samples at JAEA; Current status and development of analytical method for isotope ratios of plutonium particles

Magara, Masaaki; Usuda, Shigekazu; Sakurai, Satoshi; Shinohara, Nobuo; Esaka, Fumitaka; Kokubu, Yoko; Suzuki, Daisuke; Yasuda, Kenichiro; Lee, C. G.; Inagawa, Jun; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-29-Kai Nenji Taikai Rombunshu (CD-ROM), 6 Pages, 2008/00

JAEA has been developing, under the auspices of the Ministry of Education, Culture, Sports, Science and Technology of Japan, analytical techniques for ultra-trace amounts of nuclear materials in the environmental samples in order to contribute to the strengthened safeguards system. In January 2003, JAEA was qualified as a member of the IAEA network analytical laboratories (NWAL) for environmental sample analysis. Since then, JAEA has conducted the analysis of domestic and the IAEA samples. Two techniques, bulk and particle analyses, are available for the environmental samples and the latter method generally provides more detailed information about history of nuclear materials in a facility. However, isotope ratios of uranium are measured in the particle analysis at present and it is wished to develop analytical method for isotope ratios of plutonium in individual particles. We commence the development of the plutonium particle analysis and the consideration of age-dating for plutonium particles through the atomic ratio of Pu-241 and Am-241.

Journal Articles

Challenge to ultra-trace analytical techniques of nuclear materials in environmental samples for safeguards at JAERI; Methodologies for physical and chemical form estimation

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:42.17(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.

Journal Articles

Synthesis and characterization of nickel-copper hydroxide acetate, NiCu(OH)$$_{3.1}$$(OCOCH$$_{3}$$)$$_{0.9}$$ $$cdot$$ 0.9H$$_{2}$$O

Kozai, Naofumi; Mitamura, Hisayoshi; Fukuyama, Hiroyasu; Esaka, Fumitaka; Komarneni, S.*

Microporous and Mesoporous Materials, 89(1-3), p.123 - 131, 2006/03

 Times Cited Count:9 Percentile:36.23(Chemistry, Applied)

Layered transition metal hydroxide salt (LTMHS) is a group of anion-exchangeable layered compounds. Although LTMHSs have recentely attracted attention of researches on anion exchange and intercalation, very limited numbers of reports have been published on their synthesis, characteristics, and applications. This paper describes basic characteristics of a new LTMHS, nickel-copper hydroxide acetate. Hydrothermal Heating of an aqueous solution containing nickel acetate, copper acetate, and hydrogen peroxide to 150$$^{o}$$C for 4h yielded a layered compound with an analytical composition of NiCu(OH)$$_{3.1}$$(OCOCH$$_{3}$$)$$_{0.9}$$ 0.9H$$_{2}$$O. This compound does not take up Cl$$^{-}$$ and NO$$_{3}$$$$^{-}$$ in aqueous solution but takes up multivalent anions and shows high selectivity in uptake of toxic SeO$$_{3}$$$$^{2-}$$ and AsO$$_{4}$$$$^{3-}$$. This compound may find applicarion in the removal of those toxic anions form natural water and wastewater rich in Cl$$^{-}$$ and NO$$_{3}$$$$^{-}$$.

Journal Articles

Synthesis and characterization of copper hydroxide acetate with a layered discoid crystal

Kozai, Naofumi; Mitamura, Hisayoshi; Fukuyama, Hiroyasu; Esaka, Fumitaka; Komarneni, S.*

Journal of Materials Research, 20(11), p.2997 - 3003, 2005/11

Layered transition metal hydroxide salt (LTMHS) is a group of anion-exchangeable layered compounds. LTMHSs have lately attraced attention of researchs on anion exchange and intercalation but very limited numbers of reports have been published on their synthesis, characteristics, and application. This study reports basic properties of a layered copper hyroxide acetate synthesized by a method modified from that of the previous studies. Titration of copper acetate solution with a dilute NaOH solution to pH 6.5 and subsequent aging at 313 K yielded a layered copper hydroxide acetate. This compound has some properties similar to those of the previously known copper hydroxide acetate, Cu$$_{2}$$(OH)$$_{3}$$(OCOCH$$_{3}$$)H$$_{2}$$O. The present copper hydroxide acetate is dissimilar to the previous compound in morphology, stability of bonding between the interlayer acetate ions and the matrix hydroxides, and reaction with anions in aqueous solutions.

Journal Articles

Study on the etching conditions of polycarbonate detectors for particle analysis of safeguards environmental samples

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:10 Percentile:59.05(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.

Journal Articles

R&D on safeguards environmental sample analysis at JAERI

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

Journal Articles

Development of analytical techniques for safeguards environmental samples

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 $$^{234}$$U/$$^{238}$$U and $$^{236}$$U/$$^{238}$$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.

Journal Articles

Current status and newly introduced analytical techniques for safeguards environmental samples at JAERI

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.

Journal Articles

Efficient isotope ratio analysis of uranium particles in swipe samples by total-reflection X-ray fluorescence spectrometry and secondary ion mass spectrometry

Esaka, Fumitaka; Watanabe, Kazuo; Fukuyama, Hiroyasu; Onodera, Takashi; Esaka, Konomi; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu

Journal of Nuclear Science and Technology, 41(11), p.1027 - 1032, 2004/11

 Times Cited Count:53 Percentile:95.25(Nuclear Science & Technology)

A new particle recovery method and a sensitive screening method were developed for subsequent isotope ratio analysis of uranium particles in safeguards swipe samples. The particles in the swipe sample were recovered onto a carrier by means of vacuum suction 8211; impact collection method. When grease coating was applied to the carrier, the recovery efficiency was improved to 48 %, which is superior to that of conventionally-used ultrasoneration method. Prior to isotope ratio analysis with secondary ion mass spectrometry (SIMS), total reflection X-ray fluorescence spectrometry (TXRF) was applied to screen the sample for the presence of uranium particles. By the use of Si carriers in TXRF analysis, the detection limit of 22 pg was achieved for uranium. By combining these methods with SIMS, the isotope ratios of $$^{235}$$U/$$^{238}$$U for individual uranium particles were efficiently determined.

Journal Articles

Interfacial properties of a direct bonded Nd-doped YVO$$_{4}$$ and YVO$$_{4}$$ single crystal

Sugiyama, Akira; Nara, Yasunaga; Wada, Kengo*; Fukuyama, Hiroyasu

Journal of Materials Science; Materials in Electronics, 15(9), p.607 - 612, 2004/09

Laser crystal bonding of a neodymium-doped yttrium orthovanadate (Nd: YVO$$_{4}$$) and a non-doped yttrium orthovanadate (YVO$$_{4}$$) crystal as a cold finger has been demonstrated. Instead of a traditional chemical treatment, a newly developed dry etching process was applied to the preparation for contact of mechanically polished surfaces. In the subsequent heat treatment process, stable heating at 873 K was required to prevent precipitation at the bonded interface. The bonded interface of 3 mm $$times$$ 3 mm was investigated by optical scattering and wavefront distortion measurements. The scattering density around the bonded interface was less than 4.6$$times$$10$$^{6}$$ /cm$$^{3}$$ and the wavefront distortion caused by the bonded region was assumed to be around 0.04-wave at 633 nm. Additional magnified inspection showed that atoms in the bonded region were well arranged with the same regularity as the bulk crystal. The diffusion coefficient of Nd$$^{3+}$$ ions in the YVO$$_{4}$$ crystal was estimated at 2.3$$times$$10$$^{-23}$$ m$$^{2}$$/sec at 873 K.

Journal Articles

Isotope ratio analysis of individual uranium particles for safeguards

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.

Journal Articles

Nd:YVO$$_{4}$$ and YVO$$_{4}$$ laser crystal integration by a direct bonding technique

Sugiyama, Akira; Fukuyama, Hiroyasu; Katsumata, Masaki*; Okada, Yukikatsu*

Integrated Optical Devices: Fabrication and Testing (Proceedings of SPIE Vol.4944), p.361 - 368, 2003/00

We report recent progress in bonding of crystals used in microchip lasers, Nd:YVO$$_{4}$$ and non-doped YVO$$_{4}$$ crystal that functions as a cold finger. The bonding technique consists of a dry etching process for polished crystal surfaces to be bonded and a successive transformation from hydrogen bonding to oxygen-bridged bonding at temperature below half of the melting point of crystal. Roughness of the surfaces was less than 0.2-lambda at 633 nm. After the etching of around 30 nm by an argon ion beam, the surfaces were contacted in the clean ambient, then heat treatment was done for 50 hours in a vacuum furnace. To evaluate the bonded region, we made optical scattering measurements, and laser oscillation tests pumped by a laser diode with the output power of 20 W. From these experiments, it was clear that the number of defects on the bonded surface is much smaller than that of the intrinsic defects, and the integrated crystal, improving thermal conductivity, can produce twice of laser output power compared with a usual one.

Journal Articles

Development for ultra-trace analysis method of U and Pu in safeguards environmental samples at the clean facility

Takahashi, Masato; Magara, Masaaki; Sakurai, Satoshi; Kurosawa, Setsumi; Esaka, Fumitaka; Taguchi, Takuji; Takai, Konomi; Fukuyama, Hiroyasu; Lee, C. G.; Yasuda, Kenichiro; et al.

Dai-23-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, 8 Pages, 2002/09

Based on the strengthen safeguard program of the IAEA to detect undeclared nuclear activities, the method of precise and accurate isotope ratio determination for uranium and plutonium in the environmental samples (cotton swipes) has been developed at JAERI. The samples should be treated in clean environment in order to secure the analytical reliability by eliminating external contamination from the samples containing trace amount of uranium and plutonium. Since the measurement by ICP-MS is favorable to bulk analysis from view points of analytical capacity and operation simplicity, we have studied sample preparation procedures for the trace amount of uranium and plutonium to be applied to ICP-MS. Up to the present, interfering factors involved during analytical processes and the ICP-MS measurement of uranium and plutonium were examined. As a result, uranium and plutonium isotope measurement more than 100 pg and 100 fg, respectively, became possible at JAERI clean facility. At presentation, other progress in the development will be reported.

JAEA Reports

JAEA Reports

Density measurements of micro defects inside optical materials using a laser tomography method

Fukuyama, Hiroyasu*; Sugiyama, Akira

JAERI-Tech 2000-058, 33 Pages, 2000/11

JAERI-Tech-2000-058.pdf:5.98MB

no abstracts in English

Journal Articles

Feasibility study of a direct bonding technique for laser crystals

Sugiyama, Akira; Fukuyama, Hiroyasu*; Kataoka, Yohei*; Nishimura, Akihiko; Okada, Yukikatsu*

Advanced Optical Manufacturing and Testing Technology 2000 (Proceedings of SPIE Vol.4231), p.261 - 268, 2000/11

no abstracts in English

Journal Articles

Optics developments for CPA lasers in JAERI

Sugiyama, Akira; Fukuyama, Hiroyasu*; Katsurayama, Masamichi*; Anzai, Yutaka*

Denki Gakkai Hikari, Ryoshi Debaisu Kenkyukai OQD-00-50, p.23 - 28, 2000/10

no abstracts in English

Oral presentation

Development in FT-TIMS method for particle analysis of safeguards environmental samples

Iguchi, Kazunari; Lee, C. G.; Inagawa, Jun; Suzuki, Daisuke; Esaka, Fumitaka; Esaka, Konomi; Fukuyama, Hiroyasu; Onodera, Takashi; Magara, Masaaki; Watanabe, Kazuo; et al.

no journal, , 

no abstracts in English

Oral presentation

Development of safeguards environmental sample analysis for nuclear non-proliferation

Esaka, Fumitaka; Magara, Masaaki; Lee, C. G.; Suzuki, Daisuke; Kokubu, Yoko; Yasuda, Kenichiro; Miyamoto, Yutaka; Inagawa, Jun; Onodera, Takashi; Fukuyama, Hiroyasu; et al.

no journal, , 

JAEA is one of the IAEA network laboratories for safeguards environmental sample analysis. We are analyzing the samples routinely and developing more effective techniques. In this presentation, the development of uranium particle analysis using SIMS and FT-TIMS techniques and a plan for the analysis of Pu/MOX particles are shown.

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