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Journal Articles

Isotope-selective dissociation of diatomic molecules by terahertz optical pulses

Ichihara, Akira; Matsuoka, Leo*; Segawa, Etsuo*; Yokoyama, Keiichi

Physical Review A, 91(4), p.043404_1 - 043404_7, 2015/04

 Times Cited Count:10 Percentile:53.72(Optics)

We propose a new method for isotope-selective dissociation of diatomic molecules in the gas phase by using two kinds of terahertz-pulse fields. The first field consists of a train of pulses, which composes a frequency comb, excites the selected isotope into highly-rotationally excited state. The second intense pulse field dissociates the excited molecule by further rotational excitations. We performed wave-packet computations using the lithium chlorides $$^{7}$$Li$$^{35}$$CL and $$^{7}$$Li$$^{37}$$Cl to demonstrate the applicability of our method. Nearly 20% of $$^{7}$$Li$$^{37}$$Cl in the lowest rovibrational state is dissociated in the designed pulse fields, while the dissociation probability is negligible in $$^{7}$$Li$$^{35}$$Cl. This method is expected to be applicable to other diatomic molecules, and to molecular ensembles whose rotational states spread in energy.

Journal Articles

Optical frequency comb opens up highly efficient isotope separation of long-lived fission products; The Quantum walk to reduce radioactive waste

Yokoyama, Keiichi; Matsuoka, Leo*

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 56(8), p.525 - 528, 2014/08

With respect to the isotope separation of cesium, one of the long-lived fission products, the background, principle, feasibility, and research activity in Kansai Photon Science Institute are described.

Journal Articles

High thermo-separation efficiency of $$^{99m}$$Tc from molten $$^{100}$$MoO$$_{3}$$ samples by repeated milking tests

Nagai, Yasuki; Kawabata, Masako; Sato, Nozomi; Hashimoto, Kazuyuki; Saeki, Hideya; Motoishi, Shoji*

Journal of the Physical Society of Japan, 83(8), p.083201_1 - 083201_4, 2014/07

 Times Cited Count:10 Percentile:60.3(Physics, Multidisciplinary)

Journal Articles

Numerical analysis of fractional distillation characteristics for radioactive metallic waste vaporized in the shape of atomic beam

Akaoka, Katsuaki; Maruyama, Yoichiro

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(2), p.127 - 134, 2005/06

The fractional distillation characteristics of the materials used for the reactor pressure vessel made of ASTM A302B and the structures in reactor made of SUS304 which are the radioactive metallic waste of Japan Power Demonstration Reactor (JPDR) were analyzed numerically. In the simulation, the vaporization rates of the components of the waste were calculated by using the Langmuir's equation and Henry's law. As the result of simulation, it was calculated that $$^{152}$$Eu, $$^{154}$$Eu, $$^{14}$$C and $$^{94}$$Nb can be reduced to less than clearance level by the fractional distillation. On the ASTM A302B case, it was pointed out that the other radioactive nuclei which are $$^{54}$$Mn, $$^{55}$$Fe, $$^{60}$$Co, $$^{59}$$Ni and $$^{63}$$Ni satisfy clearance level after 77 years cooling down. On the SUS304 case, it was pointed out that $$^{59}$$Ni and $$^{63}$$Ni must be separated to satisfy clearance level using isotope separation.

Journal Articles

Silicon isotope separation utilizing infrared multiphoton dissociation of Si$$_{2}$$F$$_{6}$$ irradiated with two-frequency CO$$_{2}$$ laser lights

Yokoyama, Atsushi; Oba, Hironori; Hashimoto, Masashi; Katsumata, Keiichi; Akagi, Hiroshi; Ishii, Takeshi*; Oya, Akio*; Arai, Shigeyoshi*

Applied Physics B, 79(7), p.883 - 889, 2004/11

 Times Cited Count:9 Percentile:42.79(Optics)

Silicon isotope separation has been done utilizing the Infrared Multiphoton Dissociation of Si$$_{2}$$F$$_{6}$$ irradiated with two-frequency CO$$_{2}$$ laser lights. The two-frequency excitation method improved the separation efficiency with keeping the high enrichment factors. For example, Si$$_{2}$$F$$_{6}$$ with the $$^{28}$$Si fraction of 99.4 % was obtained at 40.0 % dissociation of Si$$_{2}$$F$$_{6}$$ after the simultaneous irradiation of 100 pulses with 966.23 cm$$^{-1}$$ photons (0.089 J/cm$$^{2}$$) and 954.55 cm$$^{-1}$$ photons (0.92 J/cm$$^{2}$$), while 1000 pulses were needed to obtain 99.0 % of $$^{28}$$Si at 27.2 % dissociation in the case of single frequency irradiation at 954.55 cm$$^{-1}$$ (0.92 J/cm$$^{2}$$). The single-step enrichment factors of $$^{29}$$Si and $$^{30}$$Si increased with increasing Si$$_{2}$$F$$_{6}$$ pressure. The reason for this enhancement has been discussed in terms of the rotational and vibrational relaxations by collisions with ambient gases.

JAEA Reports

Numerical analysis of fractional distillation characteristics for radioactive metallic waste

Akaoka, Katsuaki; Maruyama, Yoichiro

JAERI-Research 2004-012, 12 Pages, 2004/08

JAERI-Research-2004-012.pdf:3.52MB

The fractional distillation characteristics at between 0 $$^{circ}$$C and 2500 $$^{circ}$$C(the rate is 200 $$^{circ}$$C/h) of radioactive metallic waste for JPDR which mainly consists of stainless steel were analyzed numerically. In the simulation, the vaporization rates of the components of JPDR waste were calculated by using the Langmuir's equation and Henry's law. As the results, it was calculated that $$^{152,154}$$Eu, $$^{14}$$C and $$^{94}$$Nb can be removed by the fractional distillation. On the other hand, $$^{54}$$Mn and $$^{55}$$Fe can be reduced by cooling them for about 30 years. Therefore, by removing $$^{59,63}$$Ni and $$^{60}$$Co using laser separation method, it will be possible to reduce the radioactive metallic waste by less than one one-hundredth.

JAEA Reports

Research of vacuum distillation for metals; Elemental separation of duralumin

Akaoka, Katsuaki; Maruyama, Yoichiro

JAERI-Research 2003-022, 16 Pages, 2003/10

JAERI-Research-2003-022.pdf:1.56MB

We measured and simulated the characteristics of vacuum distillation for duralumin (Aluminum alloy 7075: Al-5.6Zn-2.5Mg-1.6Cu-0.25Cr). In the experiment, the duralumin (378.7 mg) was heated to 1500$$^{circ}$$C (the rate is 200$$^{circ}$$C/hour) and vaporized. The ion current of components within the vapor using mass spectrometer was measured. In the simulation, the vaporization rate of components within vapor was calculated by using the formula of Langmuir and the law of Raoult. The simulation agreed well with the experiment, and it was found that the group of Al, Cu and Cr, and the group of Mg and Zn could be separated by the vacuum distillation.These results show that the radioactive wastes can be reduced using the vacuum distillation.

Journal Articles

$$gamma$$-ray spectroscopy for neutron-rich A$$approx$$160-170 nuclei; The $$beta^{-}$$ decay of $$^{159}$$Pm, $$^{160-162}$$Sm, $$^{162}$$Eu, $$^{164-166}$$Gd, and $$^{166-168}$$Tb

Asai, Masato; Ichikawa, Shinichi; Tsukada, Kazuaki; Osa, Akihiko; Nishinaka, Ichiro; Nagame, Yuichiro; Kojima, Yasuaki*; Shibata, Michihiro*

Fission and Properties of Neutron-Rich Nuclei; Proceedings of 3rd International Conference, p.227 - 232, 2003/10

Structure of neutron-rich A$$approx$$160-170 nuclei produced in the proton-induced fission has been studied through $$gamma$$-ray spectroscopy using an on-line isotope separator. $$beta^{-}$$ decays of $$^{159}$$Pm, $$^{161,162}$$Sm, and $$^{165,166}$$Gd have been observed for the first time, and their half-lives were determined. Excited states of their daughter nuclei were revealed. $$gamma$$ rays following the $$beta^{-}$$ decay of $$^{162}$$Eu and $$^{164}$$Gd have been also observed. The results suggest that the ground state of $$^{162}$$Eu would have a spin 5 or 6.

JAEA Reports

Carbon-14 in neutron-irradiated graphite for graphite-moderated reactors (Joint research)

Fujii, Kimio; Matsuo, Hideto*

JAERI-Review 2002-034, 44 Pages, 2002/12

JAERI-Review-2002-034.pdf:3.34MB

Graphite material is used as a moderator and reflector of graphite-moderated gas-cooled reactors such as the Tokai Nuclear Power Station of Japan Atomic Power Company. For the decommissioning of those reactors, it is very important to obtain the density of carbon-14 in the graphite of which half-time is very long, and the development of the reduction technique for density of carbon-14 is one of the main technical issues as well. The reactor ceased the commercial operation on March 1998, and is in the process of the decommissioning. Technical developement on nuclear graphite disposal is one of the main issues, and it is pointed out that carbon-14 density is an impotant factor for the treatment on the disposal of the nuclear graphite. In order to resolve the problem, literatures survey was carried out for describing the status of technical development on resolving the problem. This report describes the outline of the literatures surveyed and the list of the related literatures is attached as well.

JAEA Reports

Proceedings of the Workshop on Applications of IRFEL and Nuclear Isomers; Septemper 28, 2001, JAERI, Tokai, Japan

Yamauchi, Toshihiko; Hayakawa, Takehito; Shizuma, Toshiyuki

JAERI-Conf 2002-007, 54 Pages, 2002/08

JAERI-Conf-2002-007.pdf:5.32MB

The workshop on application of free-electron laser (FEL) and nuclear isomer study was held at Tokai Research Establishment of JAERI on September 28. The workshop was devoted to the discussions and the presentations of two thema as follows: Six papers associated with the laser compton gamma-ray, the photonuclear physics and the nuclear astrophysics using the gannma-ray produced by the T3 laser were presented in the morning session. Seven papers including an invited talk on the behavior of molecules in intense laser light fields and associated with the chemical decomposition of dioxin, the silicon isotope separetion, the infrared photoexcitation spectroscopy, the laser-tissue interaction and the single-wall carbon nanotube and nanohorn by FEL etc. were also presented in the afternoon session. The intensive discussion was exchanged among approximately 50 participants. Each performance during the first workshop was fully telecomunicated by a video conference system between Tokai and Kizu (Kansai Research Establishment) sites.

Journal Articles

Numerical estimation method of the hydrogen isotope inventory in the hydrogen isotope separation system for fusion reactor

Iwai, Yasunori; Yamanishi, Toshihiko; Nakamura, Hirofumi; Isobe, Kanetsugu; Nishi, Masataka; Willms, R. S.*

Journal of Nuclear Science and Technology, 39(6), p.661 - 669, 2002/06

 Times Cited Count:10 Percentile:56.08(Nuclear Science & Technology)

no abstracts in English

Journal Articles

High enrichment of $$^{28}$$Si by infrared multiple photon decomposition of Si$$_{2}$$F$$_{6}$$

Yokoyama, Atsushi; Oba, Hironori; Shibata, Takemasa; Kawanishi, Shunichi*; Sugimoto, Shunichi*; Ishii, Takeshi*; Oya, Akio*; Miyamoto, Yoshiki*; Isomura, Shohei*; Arai, Shigeyoshi*

Journal of Nuclear Science and Technology, 39(4), p.457 - 462, 2002/04

 Times Cited Count:2 Percentile:17.54(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

A Design stufy of hydrogen isotope separation system for ITER-FEAT

Iwai, Yasunori; Yamanishi, Toshihiko; Nishi, Masataka

JAERI-Tech 2001-027, 29 Pages, 2001/03

JAERI-Tech-2001-027.pdf:1.11MB

no abstracts in English

Journal Articles

Production of polarized beam of unstable nuclei via ion surface interaction at grazing incidence

Otsubo, Takashi*; Oya, Susumu*; Goto, Jun*; *; Muto, Suguru*; Osa, Akihiko; Koizumi, Mitsuo; Sekine, Toshiaki

JAERI-Review 99-025, TIARA Annual Report 1998, p.206 - 207, 1999/10

no abstracts in English

Journal Articles

Polarized beam of unstable nuclei via ion beam surface interaction at grazing incidence

*; *; *; *; *; *; *; Muto, Suguru*; Osa, Akihiko; Koizumi, Mitsuo; et al.

Hyperfine Interactions, 120-121(1-4), p.695 - 699, 1999/00

no abstracts in English

Journal Articles

Recent studies of unstable nuclei far from stability with the on-line isotope separators of JAERI

Sekine, Toshiaki; Ichikawa, Shinichi; Osa, Akihiko; Koizumi, Mitsuo; Iimura, Hideki; Tsukada, Kazuaki; Nishinaka, Ichiro; Hatsukawa, Yuichi; Nagame, Yuichiro; Asai, Masato*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 239(1), p.127 - 131, 1999/00

 Times Cited Count:2 Percentile:21.59(Chemistry, Analytical)

no abstracts in English

JAEA Reports

Proceedings of Symposium on Nuclear Fusion and Fission of Heavy Elements, March 24$$sim$$25, 1997, JAERI, Tokai, Japan

Mitsuoka, Shinichi; Ikezoe, Hiroshi; Iwamoto, Akira; Nagame, Yuichiro

JAERI-Conf 97-009, 106 Pages, 1997/07

JAERI-Conf-97-009.pdf:4.02MB

no abstracts in English

Journal Articles

Low-lying O$$^{+}$$ states in $$^{124-130}$$Ba

Asai, Masato*; *; Osa, Akihiko; Koizumi, Mitsuo; Sekine, Toshiaki; *; Yamamoto, Hiroshi*; Kawade, Kiyoshi*

"Fuanteikaku No Rikogaku Oyobi Kaku Keisokuho(II)" Ni Kansuru Semmon Kenkyukai Hokokusho, 0, p.97 - 100, 1997/00

no abstracts in English

Journal Articles

A Five-HPGe detector system for $$gamma$$-$$gamma$$ angular correlation measurements for mass-separated short-lived nuclei

Asai, Masato*; Kawade, Kiyoshi*; *; Osa, Akihiko; Koizumi, Mitsuo; Sekine, Toshiaki

Nuclear Instruments and Methods in Physics Research A, 398, p.265 - 275, 1997/00

 Times Cited Count:6 Percentile:50.77(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Development of a laser ion source with pulsed ion extraction

Koizumi, Mitsuo; Osa, Akihiko; Sekine, Toshiaki; *

Nuclear Instruments and Methods in Physics Research B, 126(1-4), p.100 - 104, 1997/00

 Times Cited Count:8 Percentile:57.04(Instruments & Instrumentation)

no abstracts in English

59 (Records 1-20 displayed on this page)