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Journal Articles

High spectral resolution of diode laser absorption spectroscopy for isotope analysis using a supersonic plasma jet

Kuwahara, Akira; Aiba, Yasuaki*; Yamasaki, Shinya*; Nankawa, Takuya; Matsui, Makoto*

Journal of Analytical Atomic Spectrometry, 33(7), p.1150 - 1153, 2018/07

 Percentile:100(Chemistry, Analytical)

Although high-temperature plasma sources have been used for direct isotope analysis of solid samples, the spectral resolution of diode laser absorption spectroscopy in high-temperature plasma is limited by the Doppler broadening of atomic absorption lines. Thus, a decrease in translational temperature is necessary to enhance the spectral resolution and distinguish isotope shifts due to mass number. In this study, a supersonic plasma wind tunnel, also called an arc-jet plasma wind tunnel, was used to enhance spectral resolution drastically, and a demonstration was carried out using natural stable xenon isotopes. As a result, the temperature was found to be about 180 K and the spectral resolution was about one order of magnitude higher than that of the conventional high-temperature source. Additionally, the method proposed herein was verified by using two xenon isotopes.

Journal Articles

Development of an isotope analysis method based on diode laser absorption spectroscopy using an arc-jet plasma wind tunnel

Kuwahara, Akira; Aiba, Yasuaki*; Nankawa, Takuya; Matsui, Makoto*

Journal of Analytical Atomic Spectrometry, 33(5), p.893 - 896, 2018/05

 Times Cited Count:1 Percentile:47.42(Chemistry, Analytical)

no abstracts in English

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Oral presentation

Transport properties of Cs to refractory on melting volume reduction process

Osugi, Takeshi; Hanawa, Ritsu; Ito, Keisuke; Kuwahara, Akira; Nakashio, Nobuyuki; Kozawa, Kazushige; Nakashima, Kunihiko*; Saito, Noritaka*; Okoshi, Minoru

no journal, , 

Oral presentation

Application of high enthalpy wind tunnel to isotope ratio measurement by enhancement of wavelength resolution

Kuwahara, Akira; Nankawa, Takuya; Matsui, Makoto*

no journal, , 

In this research, we propose a novel laser absorption spectroscopy (LAS) system combined with high enthalpy wind tunnel to measure the isotope ratio of radioactive elements in nuclear fuel and radioactive waste. In detecting the isotope ratio of radioactive elements, spectroscopic technique with high wavelength selectivity would be effective, but no established method is available due to the small differences in energy levels of isotopes. We use the supersonic nozzle in high enthalpy wind tunnel and applied LAS to the downstream flow to enhance the wavelength resolution by decreasing the spectral width attribute to the flow temperature. In this paper, first the measurable range of atomic species was discussed. Next, we demonstrated measurements of the isotope ratio by using xenon gas. As a result, isotope shifts of xenon atoms were detected and the spectral width was evaluated for a variation of the gas temperature.

Oral presentation

Chemical form analysis of moved Cs into refractory

Kuwahara, Akira; Osugi, Takeshi; Hanawa, Ritsu; Ito, Keisuke; Nakashio, Nobuyuki; Kozawa, Kazushige; Meguro, Yoshihiro; Akabori, Mitsuo; Okamoto, Yoshihiro; Nakashima, Kunihiko*; et al.

no journal, , 

In order to obtain the knowledge about cesium accumulations into the refractory in ash melting of decontamination waste, the immersion test was worked by immersing the refractory into melting slug including cesium, and cesium chemical forms in the refractory were analyzed.

Oral presentation

Separation and recovery of radioactive cesium and strontium by metal-organic-frameworks

Nankawa, Takuya; Ogoshi, Yurie; Kuwahara, Akira; Yamada, Teppei*; Zanella, M.*; Jansat, S.*; Manning, T.*; Rosseinsky, M.*

no journal, , 

Radioactive Cesium(Cs) and Strontium(Sr) in liquid waste can be separated by porous materials such as zeolite. The pore sizes of these materials seems to identify metal ion radius or hydrated ion radius of Cs or Sr. But since it is very difficult to change the pore sizes of these materials, we cannot investigate the relationship between the pore sizes and Cs or Sr uptake behavior of these materials. And since the frameworks of these materials are rigid, it is very hard to recover Cs or Sr absorbed in the materials and we have to dispose Cs or Sr containing material as nuclear waste. But if Cs and Sr can be recovered from the materials, we can make use of these radioactive nuclides as radiation or heat source. On the other hand, metal-organic-frameworks (MOF) have attracted much interest in this two decades because of its fascinating characters such as gas absorption, catalytic or optical properties. The advantages of MOF over zeolites or other porous materials are a highly-ordered structure composed of metal ions and organic ligands, and highly controllable pore sizes that can be controlled by the length of ligand and ionic radii of metal ions. Moreover, structures of MOF can easily be influenced by solution phase. So, it becomes easy to recover guest ions from MOF. In this study, we synthesized a novel series of MOF, (NH$$_{4}$$)[Ln(C$$_{2}$$O$$_{4}$$)$$_{2}$$(H$$_{2}$$O)]. The structure is shown in Fig.1. All the structures the MOF are isostructural. The cell lengths and pore sizes tend to be decreased with the increase of atomic number in response to the decrease of ionic radius known as lanthanide contraction. And we investigated the behavior of Cs or Sr uptake by changing lanthanide ions in the MOF. Moreover, we found that Cs can be recovered from the MOF and we can reuse the MOF again. According to these results, we found a new material to recover Cs from radioactive liquid waste to decrease the amount of waste and make use of Cs as radiation source.

Oral presentation

Evaluation of spectral profile for saturated absorption spectroscopy

Kuwahara, Akira; Asami, Daichi*; Nishimoto, Koji*; Nankawa, Takuya; Matsui, Makoto*

no journal, , 

no abstracts in English

Oral presentation

The Effect of the pressure broadening for isotopic analysis using diode laser

Kuwahara, Akira; Aiba, Yasuaki*; Matsui, Makoto*; Nankawa, Takuya

no journal, , 

no abstracts in English

Oral presentation

Characteristic evaluation for laser spectrochemistry using arcjet plasma

Kuwahara, Akira; Aiba, Yasuaki*; Nankawa, Takuya; Matsui, Makoto*

no journal, , 

no abstracts in English

Oral presentation

Separation and recovery of radioactive ions by metal-organic-frameworks

Nankawa, Takuya; Yamada, Teppei*; Ogoshi, Yurie; Kuwahara, Akira; Alexandros, K.*; David, S.*; Marco, Z.*; Jansat, S.*; Troy, D. M.*; Matthew, J. R.*

no journal, , 

Oral presentation

Development of isotope analytical method based on diode laser absorption spectroscopy using arc-jet plasma wind tunnel

Kuwahara, Akira; Aiba, Yasuaki*; Nankawa, Takuya; Matsui, Makoto*

no journal, , 

Oral presentation

Development of high sensitive laser absorption spectroscopy system using optical cavities for isotope analysis

Kuwahara, Akira; Nankawa, Takuya; Matsui, Makoto*

no journal, , 

no abstracts in English

Oral presentation

New approach for isotope analysis using supersonic plasma jet combined with laser absorption spectroscopy

Kuwahara, Akira; Nankawa, Takuya; Matsui, Makoto*

no journal, , 

no abstracts in English

Patent

同位体分析装置及び同位体分析方法

桑原 彬; 藤平 俊夫; 南川 卓也

松井 信*

JP, 2017-064440  Patent licensing information

【課題】低濃度試料による分析でも高い精度で同位体の分析を行うことが可能な同位体分析装置を提供する。 【解決手段】本発明に係る同位体分析装置1は、入射側高反射ミラー151と、前記入射側高反射ミラー151とで対を成し、光キャビティー155を形成する出射側高反射ミラー152と、前記入射側高反射ミラー151にレーザー光を入射するレーザー光入射部(光学系45)と、前記出射側ポート140から出射する光を受光する光検出部(光電子増倍管50)と、前記光検出部(光電子増倍管50)の出力をスペクトル信号に変換するスペクトル信号変換部(オシロスコープ70、コンピューター80)と、からなり、前記光キャビティー155内でドップラーフリースペクトルを発現させると共に、前記スペクトル信号変換部(オシロスコープ70、コンピューター80)で得られる、特定元素の各同位体のドップラーフリースペクトル信号強度の比に基づいて同位体の分析を行うことを特徴とする。

15 (Records 1-15 displayed on this page)
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