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Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo
Journal of Nuclear Engineering and Radiation Science, 7(4), p.042002_1 - 042002_7, 2021/10
For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station (FDNPS) buildings, we propose a novel one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding. The proposed method estimates the incident position of radiation to the fiber by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of light along the fiber depends on the wavelength. Because this method measures the integrated light intensity, this method can avoid the problem of counting loss and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field. Through basic experiments using the ultraviolet light source and Sr/Y radioactive point source, basic properties of source position detection were confirmed.
Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo
Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05
Idomura, Yasuhiro; Nakata, Motoki; Yamada, Susumu; Machida, Masahiko; Imamura, Toshiyuki*; Watanabe, Tomohiko*; Nunami, Masanori*; Inoue, Hikaru*; Tsutsumi, Shigenobu*; Miyoshi, Ikuo*; et al.
International Journal of High Performance Computing Applications, 28(1), p.73 - 86, 2014/02
Times Cited Count:17 Percentile:76.23(Computer Science, Hardware & Architecture)Idomura, Yasuhiro; Nakata, Motoki; Yamada, Susumu; Machida, Masahiko; Imamura, Toshiyuki*; Watanabe, Tomohiko*; Nunami, Masanori*; Inoue, Hikaru*; Tsutsumi, Shigenobu*; Miyoshi, Ikuo*; et al.
Proceedings of 31st JSST Annual Conference; International Conference on Simulation Technology (JSST 2012) (USB Flash Drive), p.234 - 242, 2012/09
Yuri, Yosuke; Ishizaka, Tomohisa; Yuyama, Takahiro; Okumura, Susumu; Ishibori, Ikuo; Yokota, Wataru; Watanabe, Shinichi*; Kubono, Shigeru*; Oshiro, Yukimitsu*
Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.3895 - 3897, 2009/05
Miyabe, Masabumi; Oba, Masaki; Iimura, Hideki; Akaoka, Katsuaki; Maruyama, Yoichiro; Wakaida, Ikuo; Watanabe, Kazuo
AIP Conference Proceedings 1104, p.30 - 35, 2009/03
no abstracts in English
Miyabe, Masabumi; Oba, Masaki; Iimura, Hideki; Akaoka, Katsuaki; Maruyama, Yoichiro; Wakaida, Ikuo; Watanabe, Kazuo
JAEA-Research 2008-056, 24 Pages, 2008/06
For remote isotope analysis of low-decontaminated TRU fuel, we are developing an analytical technique on the basis of the resonance absorption spectroscopy for the laser-ablation plume. To improve isotopic selectivity and detection sensitivity of this technique, we measured absorption spectra of Gd atom with various conditions. As a result, high resolution spectrum was obtained from the observation of slow component of the plume produced under low-pressure rare-gas ambient. The observed narrowest linewidth of about 0.85 GHz was found to be close to the Doppler width estimated for Gd atom of room temperature. Furthermore, relaxation rate of higher meta-stable state was found to be faster than that of ground state, suggesting that use of the transition arising from ground state or lower meta-stable state is preferable for highly sensitive isotope analysis.
Yoshikawa, Hiroshi; Sakaki, Hironao; Sako, Hiroyuki; Takahashi, Hiroki; Shen, G.; Kato, Yuko; Ito, Yuichi; Ikeda, Hiroshi*; Ishiyama, Tatsuya*; Tsuchiya, Hitoshi*; et al.
Proceedings of International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS '07) (CD-ROM), p.62 - 64, 2007/10
J-PARC is a large scale facility of the proton accelerators for the multi-purpose of scientific researches in Japan. This facility consists of three accelerators and three experimental stations. Now, J-PARC is under construction, and LINAC is operated for one year, 3GeV synchrotron has just started the commissioning in this October the 1st. The completion of this facility will be next summer. The control system of accelerators established fundamental performance for the initial commissioning. The most important requirement to the control system of this facility is to minimize the activation of accelerator devices. In this paper, we show that the performances of each layer of this control system have been achieved in the initial stage.
Miyabe, Masabumi; Kato, Masaaki; Oba, Masaki; Wakaida, Ikuo; Watanabe, Kazuo; Wendt, K.*
Japanese Journal of Applied Physics, Part 1, 45(5A), p.4120 - 4122, 2006/05
Times Cited Count:2 Percentile:8.72(Physics, Applied)We developed a frequency-stabilized diode laser using magnetically induced circular dichroism. From a spectroscopic study on Rb- line, the most stable Doppler-broadened and Doppler-free lines were determined to be the transition from g=2 ground state of Rb and the crossover resonance from g=3 ground state to e=3 and 4 excited states of Rb respectively. Furthermore, we measured the fluctuation of the laser locked to the Doppler-free line to be 50kHz/8hour and thus revealed the applicability to a several-hours stabilization. The developed laser can be used as a reference laser for frequency stabilization system for multiple tunable lasers for RIMS analysis.
Miyabe, Masabumi; Oba, Masaki; Kato, Masaaki; Wakaida, Ikuo; Watanabe, Kazuo
Journal of Nuclear Science and Technology, 43(4), p.305 - 310, 2006/04
Times Cited Count:13 Percentile:65.83(Nuclear Science & Technology)We are developing an resonance ionization spectrometric apparatus aiming at an analysis of a radioactive isotope of calcium (Ca) in nuclear waste materials. The developed system consists of the reference laser whose frequency was locked on a Doppler-free absorption line of 85Rb and the computer-controlled fringe offset lock system which transfer frequency stability of the reference laser to slave lasers for Ca excitation. With heterodyne spectroscopy and laser induced fluorescence spectroscopy of Ca, it was confirmed that the developed apparatus was suitable for resonance ionization spectrometric analysis.
Miyabe, Masabumi; Geppert, C.*; Kato, Masaaki; Oba, Masaki; Wakaida, Ikuo; Watanabe, Kazuo; Wendt, K. D. A.*
Journal of the Physical Society of Japan, 75(3), p.034302_1 - 034302_10, 2006/03
Times Cited Count:18 Percentile:65.97(Physics, Multidisciplinary)High-resolution resonance ionization spectroscopy has been utilized to determine a precise ionization potential of Ca. Three-step resonance excitation with single-mode extended cavity diode lasers populates long and unperturbed Rydberg series of 4snp (1P1) and 4snf (1F3) states in the rage of n=20-150. By using an extended Ritz formula for quantum defect, the series convergence limit has been determined to be 49305.9240 (20) cm with the accuracy improved one order of magnitude higher than previously reported ones.
Miyabe, Masabumi; Oba, Masaki; Kato, Masaaki; Wakaida, Ikuo; Watanabe, Kazuo
JAERI-Tech 2005-043, 27 Pages, 2005/08
Multi-step resonance ionization spectrometry for long-lived nuclei in nuclear waste materials requires laser sources having high frequency stability and tunability. In this study we have developed a novel frequency control system consisting of digital circuitry and computer to improve the frequency tunability of the developed laser stabilization system using dichroic atomic vapor laser lock (DAVLL) and fringe offset lock (FOL) techniques. Based on the heterodyne experiment and multi-step laser induced fluorescence spectroscopy of atomic Ca, the frequency stability and tunability of the developed system were evaluated.
Miyabe, Masabumi; Oba, Masaki; Kato, Masaaki; Wakaida, Ikuo; Watanabe, Kazuo
JAERI-Research 2004-023, 17 Pages, 2004/11
High precision resonance ionization spectroscopy has been applied to determination of an accurate ionization potential of Ca. Three-step resonant excitation with single-mode extended cavity diode lasers populates a series of (P) and (F) Rydberg states in the rage of =20-150. By using an extended Ritz formula for quantum defect, the series convergence limit has been determined to be 49305.9240 (20) cm with the accuracy improved one order of magnitude higher than previously reported ones.
Miyabe, Masabumi; Kato, Masaaki; Oba, Masaki; Wakaida, Ikuo; Watanabe, Kazuo
JAERI-Tech 2004-065, 19 Pages, 2004/10
In nuclear waste materials there are various radionuclides to which standard analytical techniques are difficult to be applied. We are developing an analytical technique where such nuclides are ionized and mass-analyzed using diode laser based multi-step RIMS technique. The diode laser, however, has one drawback, i.e. its oscillation wavelength is readily drifted by acoustic, electric and optical noise, and thus the laser without frequency stabilization is not suitable for the analysis. In this study, we have developed (1) the diode laser whose frequency is stabilized to an intense absorption line of Rb by Zeeman effect and (2) the stabilization system where diode lasers for 3-step ionization of Ca are locked to the Rb-stabilized laser using a Fabry-perot interferometer. Additionally, to evaluate overall frequency stability of the stabilization system, fluctuations in the photoion and fluorescence signals arising from 3-step RIMS of Ca were simultaneously observed.
Miyabe, Masabumi; Oda, Koichi*; Oba, Masaki; Kato, Masaaki; Wakaida, Ikuo; Watanabe, Kazuo
JAERI-Tech 2004-064, 33 Pages, 2004/10
In nuclear waste materials there are various radionuclides to which standard analytical techniques are difficult to be applied. We are developing an analytical technique where such nuclides are analyzed using multi-step resonance ionization mass spectrometry. In this study, we have developed an external cavity diode laser applicable to the analysis. The wavelength and output power dependence on injection current and temperature were investigated for various types of laser diodes. Based on the data, we have obtained a suitable condition to operate the ECDL in stable single-mode oscillation, so that a continuous scanning range of about 100 GHz was realized. Additionaly, to evaluate the bandwidth of the developed ECDL, we have performed Doppler-free spectroscopy. The reasonable agreement of the measured isotope shift and HFS splitting with the reported values demonstrated that the developed ECDL is applicable to a precise laser spectroscopy as well as a laser trace analysis.
Suzuki, Junichi; Oku, Takayuki*; Adachi, Tomohiro*; Shimizu, Hirohiko*; Hirumachi, Tamiko*; Tsuchihashi, Takahiro*; Watanabe, Ikuo*
Journal of Applied Crystallography, 36(Part3, 1), p.795 - 799, 2003/01
no abstracts in English
Mori, Masahiro; Shoji, Teruaki; Araki, Masanori; Saito, Keiji*; Senda, Ikuo; Omori, Junji*; Sato, Shinichi*; Inoue, Takashi; Ono, Isamu*; Kataoka, Takahiro*; et al.
Nihon Genshiryoku Gakkai-Shi, 44(1), p.16 - 89, 2002/01
no abstracts in English
Takahashi, Yoshikazu; Ando, Toshinari; Hiyama, Tadao; Nakajima, Hideo; Kato, Takashi; Sugimoto, Makoto; Isono, Takaaki; Oshikiri, Masayuki*; Kawano, Katsumi; Koizumi, Norikiyo; et al.
Fusion Engineering and Design, 41(1-4), p.271 - 275, 1998/09
Times Cited Count:4 Percentile:38.68(Nuclear Science & Technology)no abstracts in English
Miyabe, Masabumi; Wakaida, Ikuo; Oba, Masaki; Kato, Masaaki; Watanabe, Kazuo
no journal, ,
We have developed a frequency stabilized laser system for RIMS analysis of a long-lived radionuclide of calcium (41Ca) in concrete waste materials. A stable reference laser has been developed using magnetically induced circular dichroism of atomic rubidium. The frequency stability was estimated to be 50kHz over 8 hour period from beat frequency measurement. To transfer the high frequency stability to the other lasers for 3-step excitation of atomic calcium, a computer-controlled fringe offset lock system has been developed as well. By using the system precise frequency tuning of 1MHz error over 1GHz scan was realized. The overall frequency tuning precision was also confirmed by a multistep fluorescence and resonance ionization spectroscopy of calcium.
Miyabe, Masabumi; Oba, Masaki; Kato, Masaaki; Wakaida, Ikuo; Watanabe, Kazuo
no journal, ,
We have been developing a continuous-wave resonance ionization mass spectrometry (cw-RIMS) apparatus aiming at an analysis of Ca radioisotope in nuclear waste materials. The optimum three-step ionization schemes of Ca were investigated and the 4snf (1F3) series members of around n=35 were found to have high isotope-selectivity and efficiency under our experimental conditions. The background noise arising from the thermal ions were negligible at a furnace current of 1500K. On the basis of these results the abundance sensitivity of 810 was demonstrated for Ca. Also we extended data on isotope shift and hyperfine structure of 4snf (1F3) series up to n=80.