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Miyomoto, Yoshiki*; Majima, Tetsuro*; Arai, Shigeyoshi*; Katsumata, Keiichi*; Akagi, Hiroshi; Maeda, Akihiko*; Hata, Hiroo*; Kuramochi, Koji*; Kato, Yoshiyasu*; Tsukiyama, Koichi*
Nuclear Instruments and Methods in Physics Research B, 269(2), p.180 - 184, 2011/01
Times Cited Count:12 Percentile:66.62(Instruments & Instrumentation)Oba, Hironori; Akagi, Hiroshi; Katsumata, Keiichi*; Hashimoto, Masashi; Yokoyama, Atsushi
Japanese Journal of Applied Physics, 47(11), p.8379 - 8381, 2008/11
Times Cited Count:4 Percentile:18.70(Physics, Applied)This paper presents a practical method for producing highly enriched silicon isotopes utilizing laser irradiation. One- or two-frequency CO laser irradiation has been employed to separate the desired isotope of silicon by means of infrared multi-photon dissociation (IRMPD) of the hexafluorodisilane (SiF) molecules using a flow reaction system. The production of SiF with Si fraction of 99.1% at a rate of 0.67 g(Si)/h was successfully accomplished with a high yield by the two-frequency laser irradiation. The enriched SiF gas with Si exceeding 31% was also continuously obtained at the production rate of 0.12 g/h by the one-frequency laser irradiation.
Yokoyama, Atsushi; Katsumata, Keiichi*; Oba, Hironori; Akagi, Hiroshi; Saeki, Morihisa; Yokoyama, Keiichi
Journal of Physical Chemistry A, 112(29), p.6571 - 6577, 2008/07
Times Cited Count:5 Percentile:15.70(Chemistry, Physical)Oxygen isotope separation has been examined by using an infrared multiphoton dissociation of 2,3-dihydropyran. Enrichment factor has been measured by the CO laser irradiation of the samples as a function of laser frequency, laser fluence, and sample pressure. Maximum enrichment factor of 751 has been obtained, and O, natural abundance of which is 0.205 %, was enriched to 60 %. Moreover, it was found that the enrichment factor increases with increasing the sample pressure, which was different from the infrared multiphoton dissociation of usual molecules. This phenomenon was discussed on the basis of a simulation by a rate equation model including a collisional vibrational relaxation.
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:10 Percentile:44.79(Optics)Silicon isotope separation has been done utilizing the Infrared Multiphoton Dissociation of SiF irradiated with two-frequency CO laser lights. The two-frequency excitation method improved the separation efficiency with keeping the high enrichment factors. For example, SiF with the Si fraction of 99.4 % was obtained at 40.0 % dissociation of SiF after the simultaneous irradiation of 100 pulses with 966.23 cm photons (0.089 J/cm) and 954.55 cm photons (0.92 J/cm), while 1000 pulses were needed to obtain 99.0 % of Si at 27.2 % dissociation in the case of single frequency irradiation at 954.55 cm (0.92 J/cm). The single-step enrichment factors of Si and Si increased with increasing SiF pressure. The reason for this enhancement has been discussed in terms of the rotational and vibrational relaxations by collisions with ambient gases.
Yokoyama, Atsushi; Oba, Hironori; Akagi, Hiroshi; Yokoyama, Keiichi; Saeki, Morihisa; Katsumata, Keiichi*
no journal, ,
no abstracts in English
Yokoyama, Atsushi; Oba, Hironori; Akagi, Hiroshi; Yokoyama, Keiichi; Saeki, Morihisa; Katsumata, Keiichi*
no journal, ,
no abstracts in English
Yokoyama, Atsushi; Oba, Hironori; Akagi, Hiroshi; Yokoyama, Keiichi; Saeki, Morihisa; Katsumata, Keiichi*
no journal, ,
no abstracts in English