Bromine-isotope selective ionization using field-free alignment of IBr isotopologues with a switched nanosecond laser pulse

Akagi, Hiroshi*; Kumada, Takayuki; Otobe, Tomohito*; Itakura, Ryuji*; Hasegawa, Hirokazu*; Oshima, Yasuhiro*

Chemistry Letters, 49(4), p.416 - 418, 2020/04

https://doi.org/10.1246/cl.200024

Isotope separation based on quantum walk

Yokoyama, Keiichi; Matsuoka, Leo*

Ryoshi Woku No Shin Tenkai; Suri Kozo No Shinka To Oyo, p.228 - 242, 2019/08

Quantum walk is the quantum mechanical counter part of the classical random walk, which is known as mathematical model of diffusion process. By applying this new concept to light-matter interaction, a new isotope separation scheme is shown to be emerged. In addition, its advancements and forthcoming challenges are introduced.

First ionization potentials of Fm, Md, No, and Lr; Verification of filling-up of 5f electrons and confirmation of the actinide series

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Beerwerth, R.*; Kaneya, Yusuke*; Makii, Hiroyuki; Mitsukai, Akina*; Nagame, Yuichiro; Osa, Akihiko; Toyoshima, Atsushi; et al.

Journal of the American Chemical Society, 140(44), p.14609 - 14613, 2018/11

https://doi.org/10.1021/jacs.8b09068

The first ionization potential (IP) yields information on valence electronic structure of an atom. IP values of heavy actinides beyond einsteinium (Es, Z = 99), however, have not been determined experimentally so far due to the difficulty in obtaining these elements on scales of more than one atom at a time. Recently, we successfully measured IP of lawrencium (Lr, Z = 103) using a surface ionization method. The result suggests that Lr has a loosely-bound electron in the outermost orbital. In contrast to Lr, nobelium (No, Z = 102) is expected to have the highest IP among the actinide elements owing to its full-filled 5f and the 7s orbitals. In the present study, we have successfully determined IP values of No as well as fermium (Fm, Z = 100) and mendelevium (Md, Z = 101) using the surface ionization method. The obtained results indicate that the IP value of heavy actinoids would increase monotonically with filling electrons up in the 5f orbital like heavy lanthanoids.

Isotope-selective ionization utilizing field-free alignment of isotopologues using a switched nanosecond laser pulse

Akagi, Hiroshi*; Kumada, Takayuki; Otobe, Tomohito*; Itakura, Ryuji*; Hasegawa, Hirokazu*; Oshima, Yasuhiro*

Applied Physics B, 124(1), p.14_1 - 14_8, 2018/01

https://doi.org/10.1007/s00340-017-6884-7

We propose and numerically simulate a method of laser isotope separation based on field-free alignment of isotopologues, utilizing an intense switched nanosecond (ns) laser field which is slowly turned on and rapidly turned off at the peak with the falling time of 200 fs. The femtosecond (fs) laser induced alignment of molecules including a heavy atom is severely disturbed by ionization because of their small ionization potential. Our simulations for IBr and IBr isotopologues demonstrate that the switched ns laser field can make isotopologues well-aligned with the reduced ionization probability at the laser intensity which is an order-of-magnitude lower than a typical intensity for field-free alignment induced by a fs laser field.

Measurement of the first ionization potential of lawrencium by surface ionization method

Sato, Tetsuya

Genshikaku Kenkyu, 61(1), p.96 - 106, 2016/09

We successfully determined the first ionization potential of lawrencium (Lr, Z=103). The result experimentally substantiated for the first time that Lr is the last member of the actinide series. Measured ionization potential suggested that Lr atom would have the electronic configuration which is different from the configuration expected based on the Periodic table. For the measurement, we have developed a novel method applied the surface ionization process. Public responses after the publication are also introduced.

Where is an appropriate place for element 103 on the periodic table?; Measurement of the first ionization potential of lawrencium

Sato, Tetsuya

Nihon Genshiryoku Gakkai-Shi ATOMO, 57(11), p.741 - 744, 2015/11

We have experimentally confirmed that Lr would be the last member of actinides series for the first time by a measurement of the first ionization potential of lawrencium (Lr, element 103). The electronic orbital of Lr atom which is estimated by the result suggests that Lr could have the outermost electronic orbital similar with group-13 elements. This work triggered a discussion concerning positions of Lr and lutetium, lanthanide homologue of Lr.

Discrepancy in the periodic table appears at element 103; Successful measurement of the first ionization potential of lawrencium, element 103

Sato, Tetsuya; Nagame, Yuichiro; Tsukada, Kazuaki

Kagaku To Kogyo, 68(9), p.824 - 826, 2015/09

We successfully confirmed that lawrencium (Lr, element 103) is the last member of actinide series by a measurement of its first ionization potential. Obtained experimental result suggested that the outermost electronic orbital of Lr atom would have p-orbital similar to elements of group-13. Our result triggered again the discussion of the position of Lr and lutetium, the lanthanide homologue of Lr, on the Periodic Table.

Successful development of a new catalyst for efficiently collecting tritium; A Breakthrough toward realization of fusion reactors

Iwai, Yasunori; Kubo, Hitoshi*; Oshima, Yusuke*

Kagaku, 70(5), p.35 - 40, 2015/05

We have successfully developed a new hydrophobic platinum catalyst for collecting tritium at nuclear fusion reactors. Catalysts used to collect tritium are called hydrophobic precious metal catalysts. In Japan, hydrophobic precious metal catalysts manufactured from polymers have been used for heavy water refinement. However, this catalyst has issues related to embrittlement to radiation and thermal stability. These technological issues needed to be solved to allow for its application to nuclear fusion reactors requiring further enrichment from highly-concentrated tritiated water. We developed a new method of manufacturing catalysts involving hydrophobic processing with an inorganic substance base. As a result, previous technological issues were able to be solved with the development of a catalyst that exhibited no performance degradation in response to radiation application of 530 kGy, a standard for radiation resistance, and maintenance of thermal stability at over 600C, which is much higher than the 70C temperature that is normally used. The catalyst created with this method was also confirmed to have achieved the world's highest exchange efficiency, equivalent to 1.3 times the previously most powerful efficiency. The application of this catalyst to the liquid phase catalytic exchange process is expected to overcome significant technological hurdles with regards to improving the reliability and efficiency of systems for collecting tritium from tritiated water.

Production of endohedral Xe-higher fullerenes by ion implantation

Watanabe, Satoshi; Katabuchi, Tatsuya*; Ishioka, Noriko; Matsuhashi, Shimpei; Muramatsu, Hisakazu*

Journal of Radioanalytical and Nuclear Chemistry, 272(3), p.467 - 469, 2007/06

https://doi.org/10.1007/s10967-007-0605-3

no abstracts in English

Application of pressure swing adsorption to water detritiation process

Iwai, Yasunori; Yamanishi, Toshihiko; Nishi, Masataka; Suzuki, Yutaka*; Kurita, Koichi*; Shimazaki, Masanori*

Journal of Nuclear Science and Technology, 42(6), p.566 - 572, 2005/06

https://doi.org/10.3327/jnst.42.566

Pressure swing adsorption has been studied as a new water processing method for a future fusion power plant which will have a large amount of tritiated water to be processed. A series of adsorption and dehydration experiments was carried out for a typical adsorbent of NaX zeolite and it was clearly observed that break through time differs in HO and HTO, that is, it is certain that NaX zeolite can separate into the tritium concentrated water and the tritium reduced water. The quick dehydration is attained by decompression and purge gas flowing. It was observed that a part of the water released by decompression was transferred by the purge gas, and the rest water was adsorbed on the adsorbent again and was gradually released by the diffusion. It is demonstrated that enlargement of pressure difference between adsorption and dehydration is effective to obtain high dehydration ratio. Furthermore, it was also verified that enough vapor removal capacity of purge gas is quite necessary to obtain high dehydration ratio.