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Journal Articles

EXAFS studies for atomic structural change induced by ion irradiation of a reactor pressure vessel steel

Iwata, Keiko; Takamizawa, Hisashi; Ha, Yoosung; Shimodaira, Masaki; Okamoto, Yoshihiro; Honda, Mitsunori; Katsuyama, Jinya; Nishiyama, Yutaka

Nuclear Instruments and Methods in Physics Research B, 511, p.143 - 152, 2022/01

 Times Cited Count:0 Percentile:34.54(Instruments & Instrumentation)

Journal Articles

Isotope shift and hyperfine structure measurements on triple resonance excitation to the autoionizing Rydberg state of atomic strontium

Iwata, Yoshihiro; Miyabe, Masabumi; Akaoka, Katsuaki; Wakaida, Ikuo

Journal of Quantitative Spectroscopy & Radiative Transfer, 275, p.107882_1 - 107882_9, 2021/11

 Times Cited Count:3 Percentile:39.43(Optics)

Following the accident at TEPCO's Fukushima Daiichi Nuclear Power Station, an isotope-selective analysis method using laser resonance ionization has been developed for strontium-90. In this study, the isotope shifts and hyperfine structure constants of stable isotopes were measured for two schemes expected to have high isotopic selectivity, and the isotope shifts of strontium-90 were evaluated using the King plot analysis. The measured strontium-90 optical isotopic selectivities ranged from $$10^3$$ to $$10^5$$, which are sufficient for analysis of real samples.

Journal Articles

Investigation on the DC Stark shifts of strontium autoionization states for isotope-selective resonance ionization

Iwata, Yoshihiro; Miyabe, Masabumi; Hasegawa, Shuichi*

Journal of Quantitative Spectroscopy & Radiative Transfer, 265, p.107549_1 - 107549_7, 2021/05

 Times Cited Count:1 Percentile:13.5(Optics)

Following the accident at TEPCO's Fukushima Daiichi Nuclear Power Station, an isotope-selective analysis method using laser resonance ionization has been developed for strontium-90. In this study, we focused on ionization via autoionization states in terms of high isotopic selectivity and ionization efficiency, and the DC Stark shifts caused by the external electric field were measured for these states. It was found that the external electric field in the ionization region has to be of the order of 0.1 V/cm or less to suppress its effect on the observed spectra.

Journal Articles

Microstructure analysis using X-ray absorption on heat-affected zone of reactor pressure vessel steel

Iwata, Keiko; Takamizawa, Hisashi; Ha, Yoosung; Okamoto, Yoshihiro; Shimoyama, Iwao; Honda, Mitsunori; Hanawa, Satoshi; Nishiyama, Yutaka

Photon Factory Activity Report 2017, 2 Pages, 2018/00

no abstracts in English

JAEA Reports

Light ion microbeam analysis / processing system and its improvement

Koka, Masashi; Ishii, Yasuyuki; Yamada, Naoto; Okubo, Takeru; Kada, Wataru*; Kitamura, Akane; Iwata, Yoshihiro*; Kamiya, Tomihiro; Sato, Takahiro

JAEA-Technology 2016-006, 41 Pages, 2016/03

JAEA-Technology-2016-006.pdf:14.03MB

A MeV-class light ion microbeam system has been developed for micro-analysis and micro-fabrication with high spatial resolution at 3-MV single-ended accelerator in Takasaki Ion Accelerators for Advanced Radiation Application of Takasaki Advanced Radiation Research Institute, Sector of Nuclear Science Research, Japan Atomic Energy Agency. This report describes the technical improvements for the main apparatus (the accelerator, beam-transport lines, and microbeam system), and auxiliary equipments/ parts for ion beam applications such as Particle Induced X-ray/Gamma-ray Emission (PIXE/PIGE) analysis, 3-D element distribution analysis using PIXE-Computed Tomography(CT), Ion Beam-Induced Luminescence (IBIL) analysis, and Proton Beam Writing with the microbeam scanning, with functional outline of these apparatus and equipments/parts.

Journal Articles

Ultrasensitive resonance ionization mass spectrometer for evaluating krypton contamination in xenon dark matter detectors

Iwata, Yoshihiro; Sekiya, Hiroyuki*; Ito, Chikara

Nuclear Instruments and Methods in Physics Research A, 797, p.64 - 69, 2015/10

 Times Cited Count:3 Percentile:26.04(Instruments & Instrumentation)

An ultrasensitive resonance ionization mass spectrometer that can be applied to evaluate krypton (Kr) contamination in xenon (Xe) dark matter detectors has been developed for measuring Kr at the parts-per-trillion (ppt) or sub-ppt level in Xe. The gas sample is introduced without any condensation into a time-of-flight mass spectrometer through a pulsed supersonic valve. Using a nanosecond pulsed laser at 212.6 nm, $$^{84}$$Kr atoms in the sample are resonantly ionized along with other Kr isotopes. $$^{84}$$Kr ions are then mass separated and detected by the mass spectrometer in order to measure the Kr impurity concentration. With our current setup, approximately 0.4 ppt of Kr impurities contained in pure argon (Ar) gas are detectable with a measurement time of 1,000 s. Although Kr detection sensitivity in Xe is expected to be approximately half of that in Ar, our spectrometer can evaluate Kr contamination in Xe to the sub-ppt level.

Journal Articles

Performance evaluation of a resonance ionization mass spectrometer developed for the FFDL system of fast reactors

Iwata, Yoshihiro; Ito, Chikara; Harano, Hideki*; Iguchi, Tetsuo*

Journal of Nuclear Science and Technology, 51(4), p.465 - 475, 2014/04

 Times Cited Count:5 Percentile:37.17(Nuclear Science & Technology)

To prevent a fuel failure event from becoming a serious radiation accident, sodium-cooled fast reactors are equipped with a system for failed fuel detection and location (FFDL). The FFDL instrument employed in the prototype fast breeder reactor Monju is based on the gas tagging method, in which precise and accurate measurements of krypton and xenon isotope ratios ($$^{78}$$Kr/$$^{80}$$Kr, $$^{82}$$Kr/$$^{80}$$Kr and $$^{126}$$Xe/$$^{129}$$Xe) must be performed in a short time. Burnup measurements also contribute to accurate determination of $$^{82}$$Kr/$$^{80}$$Kr. We have developed a highly sensitive resonance ionization mass spectrometer for the isotopic analyses, which uses resonance ionization of Kr and Xe atoms by a pulsed laser at wavelengths of 216.7 nm and 249.6 nm, respectively. In evaluating the performance of our spectrometer, we find that systematic errors caused by isotope shifts can be reduced to negligible levels, and that statistical errors of 3% at a nuclide concentration of 7 ppt can be achieved with a single measurement time of about 40 minutes for each Kr and Xe isotope ratio. This means that, within one hour, about 200 fuel assemblies can be individually identified with a probability of 99%, verifying the applicability of our spectrometer to the FFDL system of fast reactors.

Journal Articles

High sensitive and reliable FFDL technique for Monju using laser resonance ionization mass spectrometry

Aoyama, Takafumi; Ishikawa, Takashi; Ito, Chikara; Iwata, Yoshihiro; Harano, Hideki*

Transactions of the American Nuclear Society, 106(1), p.611 - 613, 2012/06

We studied the failed fuel detection and location (FFDL) system by means of laser resonance ionization mass spectrometry (RIMS). The applicability of the RIMS system for Monju and its installation were investigated in this study. It was found that the RIMS is able to identify the neighboring tag gas which is used for Monju with the 68% reliability. The newly designed RIMS system can be accommodated in the present facility and can be connected to primary cover gas lines without affects to the current FFDL function of the conventional system.

Journal Articles

Elemental mapping and estimation of elemental abundances of lichen by TIARA micro beam PIXE

Iwata, Yoshihiro*; Ishii, Keizo*; Kamiya, Tomihiro; Sato, Takahiro

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 90, 2012/01

Journal Articles

Development of high sensitive and reliable FFD and sodium leak detection technique for fast reactor using RIMS

Ito, Chikara; Araki, Yoshio; Naito, Hiroyuki; Iwata, Yoshihiro; Aoyama, Takafumi

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 12 Pages, 2012/00

no abstracts in English

Journal Articles

High sensitive and reliable FFDL technique for SFR using laser resonance ionization mass spectrometry

Ito, Chikara; Iwata, Yoshihiro; Harano, Hideki*; Iguchi, Tetsuo*; Aoyama, Takafumi

Transactions of the American Nuclear Society, 102(1), p.416 - 417, 2010/06

no abstracts in English

Journal Articles

Reduction of argon background in resonance ionization mass spectrometry for failed fuel detection and location of fast reactors

Iwata, Yoshihiro; Ito, Chikara; Aoyama, Takafumi*

KEK Proceedings 2010-10, p.52 - 62, 2010/02

For the fast reactors, rapid and accurate detection of fuel failures as well as subsequent identification of failed fuel location, if occurred, are essential to protect workers from radiation exposure and to reduce radiation contamination. A new type of failed fuel detection and location (FFDL) technique focused on the gas tagging method has been proposed by using resonance ionization mass spectrometry (RIMS) for the isotope analysis of the cover gas. Precise isotope analysis of ppt level Kr and Xe in Ar needed involves the two problems, which are the saturation of the output voltage by Ar$$^{+}$$ ions and the Ar$$_{2}$$ interference mainly with $$^{80}$$Kr. We proposed two methods, Brewster window and electrode with a slit-type hole, to decrease the adverse effect of Ar$$^{+}$$ and Ar$$_{2}$$$$^{+}$$ ions without any loss of Kr$$^{+}$$ and Xe$$^{+}$$ ion signals. The obtained measurement results using 100 ppt of Kr containing Ar standard gas show that we could successfully decrease the Ar$$^{+}$$ ion yield by one to two orders of magnitude or more and that the mass peak of $$^{80}$$Kr corresponding to its nuclide concentration of $$sim$$2 ppt was clearly observed without any obvious Ar$$_{2}$$$$^{+}$$ peak. The precision of the isotope analysis seems to be about 10% for ppt level detection of Kr and slightly better for Xe, and is dominated by statistical errors. The next step is to increase the detection efficiency of our RIMS system to reduce statistical errors for further reliability improvement of RIMS in the FFDL system.

Journal Articles

Comparative effect of $$^{12}$$C$$^{6+}$$ beam and $$gamma$$-ray irradiation on callus growth and shoot formation from lavandin isolated cells

Tsuro, Masato*; Iwata, Chizuru*; Kataoka, Rie*; Yoshihara, Ryohei; Hase, Yoshihiro

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 72, 2008/11

no abstracts in English

JAEA Reports

Editing of the environmental report; Environmental concerning activity at JAERI and JNC in the first half fiscal year of 2005

Narita, Osamu; Iwata, Noboru; Isobe, Yoshihiro; Seki, Masakazu; Kadosaka, Hidetake; Ninomiya, Kazushige; Sato, Osamu

JAEA-Technology 2006-037, 102 Pages, 2006/06

JAEA-Technology-2006-037.pdf:7.67MB

We edited and published the Environmental Report according to the law on Promotion of the Environmental Concerning Activity by means of the Publish of Environmental Concerning Data. The report included the environmental concerning activity at the Japan Atomic Energy Research Institute (JAERI) and the Japan Nuclear Fuel Cycle Development Institute (JNC) in the first half year of 2005. This report is the first one which is regulated and obligated by the law. We have made much effort for gathering the data and gained a lot of experience on editing the report. We hope this paper is useful not only for the back data of our environmental report, but also for the organization which is planning to publish the similar environmental report.

Journal Articles

Beam-palarization asymmetries for the $$p$$($$overrightarrow{gamma}$$,$$K$$$$^{+}$$)$$Lambda$$ and $$p$$($$overrightarrow{gamma}$$,$$K$$$$^{+}$$)$$Sigma$$$$^{0}$$ reactions for $$E$$$$_{gamma}$$=1.5-2.4 GeV

Zegers, R. G. T.*; Sumihama, Mizuki*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Dat$'e$, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; et al.

Physical Review Letters, 91(9), p.092001_1 - 092001_4, 2003/08

 Times Cited Count:128 Percentile:94.91(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Evidence for a narrow $$S$$ = +1 Baryon resonance in photoproduction from the neutron

Nakano, Takashi*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Date, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; Fujiwara, Mamoru; et al.

Physical Review Letters, 91(1), p.012002_1 - 012002_4, 2003/07

 Times Cited Count:1003 Percentile:99.86(Physics, Multidisciplinary)

no abstracts in English

Oral presentation

Creation of lavender volatile oil mutants using ion beam irradiation, 2; Comparative effect of $$^{12}$$C$$^{6+}$$ beam and $$gamma$$-ray irradiation on callus growth and indefinite bud formation

Tsuro, Masato*; Iwata, Chizuru*; Kataoka, Rie*; Yoshihara, Ryohei; Hase, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Measurement of sensitivity of microbeam system to zinc and platinum using standard sample made of ion exchange resin

Iwata, Yoshihiro*; Ishii, Keizo*; Yokota, Wataru; Kamiya, Tomihiro; Sato, Takahiro; Oikawa, Masakazu*

no journal, , 

no abstracts in English

Oral presentation

Reduction of argon background in the tag gas analysis for failed fuel detection and location of the fast reactor

Iwata, Yoshihiro; Ito, Chikara; Harano, Hideki*; Aoyama, Takafumi

no journal, , 

no abstracts in English

Oral presentation

The Study of highly sensitivity technique for sodium leak detection using laser resonance ionization mass spectrometry to improve fast reactor plant safety

Aoyama, Takafumi; Ito, Chikara; Araki, Yoshio; Naito, Hiroyuki; Iwata, Yoshihiro; Okazaki, Koki*; Harano, Hideki*; Watanabe, Kenichi*; Iguchi, Tetsuo*; Takegawa, Nobuyuki*; et al.

no journal, , 

no abstracts in English

90 (Records 1-20 displayed on this page)