Emission characteristics of gadolinium ions in a water Cherenkov detector

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

Progress of Theoretical and Experimental Physics (Internet), 2022(12), p.123H01_1 - 123H01_12, 2022/12

https://doi.org/10.1093/ptep/ptac157

In this work, we constructed an experimental setup based on time-resolved laser-induced luminescence spectroscopy to investigate the emission characteristics of Gd ions in water. The excitation laser wavelength was tuned in the range of 245-255 nm, and large resonant peaks were observed at 246.2 nm and 252.3 nm with measured emission lifetimes of around 3 ms. Good linearity was observed between Gd concentration and emission intensity for these two wavelengths, indicating that our setup is useful for remote monitoring of Gd concentration.

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

https://doi.org/10.1016/j.jqsrt.2021.107882

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 to , which are sufficient for analysis of real samples.

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

http://pfwww.kek.jp/acr/2017pdf/u_reports/pf17b0263.pdf

no abstracts in English

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

https://doi.org/10.1016/j.nima.2015.06.037

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, Kr atoms in the sample are resonantly ionized along with other Kr isotopes. 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.

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.

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

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

http://www-lib.kek.jp/cgi-bin/kiss_prepri.v8?KN=201025010exit=8.

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 interference mainly with Kr. We proposed two methods, Brewster window and electrode with a slit-type hole, to decrease the adverse effect of Ar and Ar 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 Kr corresponding to its nuclide concentration of 2 ppt was clearly observed without any obvious Ar 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.

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.

Evidence for a narrow = +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

https://doi.org/10.1103/PhysRevLett.91.012002

no abstracts in English

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