The Role of collision ionization of K-shell ions in nonequilibrium plasmas produced by the action of super strong, ultrashort PW-class laser pulses on micron-scale argon clusters with intensity up to 5 10 W/cm

Skobelev, I. Yu.*; Ryazantsev, S. N.*; Kulikov, R. K.*; Sedov, M. V.*; Filippov, E. D.*; Pikuz, S. A.*; Asai, Takafumi*; Kanasaki, Masato*; Yamauchi, Tomoya*; Jinno, Satoshi; et al.

Photonics (Internet), 10(11), p.1250_1 - 1250_11, 2023/11

https://doi.org/10.3390/photonics10111250

It is challenging to clearly distinguish the impacts of the optical field and collisional ionization in the evolution of the charge state of a plasma produced when matter interacts with high-intensity laser pulses. In this work, time-dependent calculations of plasma kinetics are used to show that it is possible only when low-density gaseous targets with sufficiently small clusters are used. In the case of Ar plasma, the upper limit of the cluster radius was estimated to be m.

Chemical characterization of a volatile dubnium compound, DbOCl

Chiera, N. M.*; Sato, Tetsuya; Eichler, R.*; Tomitsuka, Tomohiro; Asai, Masato; Adachi, Sadia*; Dressler, R.*; Hirose, Kentaro; Inoue, Hiroki*; Ito, Yuta; et al.

Angewandte Chemie; International Edition, 60(33), p.17871 - 17874, 2021/08

https://doi.org/10.1002/anie.202102808

The formation and the chemical characterization of single atoms of dubnium (Db, element 105), in the form of its volatile oxychloride, was investigated using the on-line gas phase chromatography technique, in the temperature range 350 - 600 C. Under the exact same chemical conditions, comparative studies with the lighter homologs of group-5 in the Periodic Table clearly indicate the volatility sequence being NbOCl TaOCl DbOCl. From the obtained experimental results, thermochemical data for DbOCl were derived. The present study delivers reliable experimental information for theoretical calculations on the chemical properties of transactinides.

Search for decay of Te with a novel recoil-decay scintillation detector

Xiao, Y.*; Go, S.*; Grzywacz, R.*; Orlandi, R.; Andreyev, A. N.; Asai, Masato; Bentley, M. A.*; de Angelis, G.*; Gross, C. J.*; Hausladen, P.*; et al.

Physical Review C, 100(3), p.034315_1 - 034315_8, 2019/09

https://doi.org/10.1103/PhysRevC.100.034315

Impregnation of a neutral extractant to hydrophobic/hydrophilic groups introduced into the polymer chain grafted onto a porous membrane

Sawaki, Kenta*; Asai, Shiho; Watanabe, Kazuo; Sugo, Takanobu*; Saito, Kyoichi*

Maku, 33(1), p.32 - 38, 2008/01

http://ci.nii.ac.jp/naid/10020130502

TOPO, tri-n-octylphosphine oxide, as a neutral extractant was impregnated to the hydrophobic group of the polymer chain grafted onto a porous hollow-fiber membrane for an efficient metal-ion collection. A diol group,i.e., adjacent hydroxyl group was introduced into poly-glycidyl methacrylate(GMA) chain grafted onto the porous hollow-fiber membrane via the epoxy-ring-opening reaction with water, followed by a reaction of the remaining epoxy group with octadecanethiol (CHSH) to form an octadecanethiol group. The diol group reduced the amount of TOPO coagulatedon the graft chain, whereas the interaction of the octadecanethiol group of the graft chain with the hydrophobic part of TOPO enabled the impregnation of TOPO to the graft chain. A 1 mmol-Bi/L bismuth chloride solution was forced to permeate through the pores of the TOPO-impregnated porous hollow-fiber membrane with a density of TOPO impregnated of 1.3 mol/kg of the GMA-grafted porous hollow-fiber membrane and the pure water flux of 0.7 m/h at 0.1 MPa and 298 K. The equilibrium binding capacity of the membrane for bismuth ions was 0.22 mol/kg of the TOPO-impregnated porous hollow-fiber membrane, which was equivalent to a binding ratio of bismuth ion to impregnated TOPO of 1.0.

Identification of Sm and Gd

Ichikawa, Shinichi; Tsukada, Kazuaki; Nishinaka, Ichiro; Iimura, Hideki; ; Nagame, Yuichiro; Asai, Masato*; Kojima, Yasuaki*; ; Shibata, M.*; et al.

Physical Review C, 58(2), p.1329 - 1332, 1998/08

https://doi.org/10.1103/PhysRevC.58.1329

no abstracts in English

Experimental study on fusion-fission, quasi-fission and multi-nulceon transfer reaction at JAEA

Hirose, Kentaro; Nishio, Katsuhisa; Nishinaka, Ichiro; Makii, Hiroyuki; Ikezoe, Hiroshi*; Orlandi, R.; Lguillon, R.; Tsukada, Kazuaki; Asai, Masato; Nagame, Yuichiro; et al.

no journal, , 

no abstracts in English

Adsorption behavior of lawrencium (Lr) on a tantalum surface

Sato, Tetsuya; Kaneya, Yusuke*; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Mitsukai, Akina*; Osa, Akihiko; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; et al.

no journal, , 

The ground state electronic configuration of lawrencium (Lr, Z =103) is predicted to be [Rn], which is different from that of the lanthanide homolog Lu [Xe] due to strong relativistic effects. According to semi-empirical considerations, volatility of Lr is expected to be higher than that of Lu. We have investigated adsorption behavior of Lr, which was produced in the reaction of Cf(B, 4n), on a tantalum (Ta) metal surface using a surface ion-source installed into the isotope separator on-line (ISOL) at the JAEA tandem accelerator facility. The observed adsorption behavior of Lr was similar to those of Tb and Lu which have relatively higher adsorption enthalpy on Ta surface. It implies that Lr would have low volatility like such as Lu and Tb.

Fission study of actinide nuclei using multi-nucleon transfer reactions

Lguillon, R.; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Makii, Hiroyuki; Nishinaka, Ichiro; Ishii, Tetsuro; Tsukada, Kazuaki; Asai, Masato; Chiba, Satoshi*; et al.

no journal, , 

Preparation of extractant impregnated porous membrane for separation of metal ions

Sawaki, Kenta*; Asai, Shiho; Domon, Sayaka*; Saito, Kyoichi*; Sugo, Takanobu*

no journal, , 

no abstracts in English

Measurement of mass-symmetric spontaneous fission of Lr

Asai, Masato; Kamada, Hiroki*; Shigekawa, Yudai*; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi; Mitsukai, Akina; Nagame, Yuichiro; Nishio, Katsuhisa; Hirose, Kentaro; et al.

no journal, , 

To clarify the fission mechanism of mass-symmetric spontaneous fissions observed around the neutron-rich Fm region, we have measured kinetic energies and mass distribution of spontaneous-fission fragments in this nuclear region precisely. The experiment was performed at the JAEA tandem accelerator facility using an on-line isotope separator (ISOL). The mass-separated Lr nuclei were implanted into thin foil, and two fragments of their spontaneous fission were coincidently measured with two Si detectors. The spontaneous fission of Lr was found to show a narrow symmetric mass distribution. On the other hand, their total kinetic energy TKE was found to be low, which is apparently different from the high-TKE symmetric fissions observed in the Fm isotopes. This indicates that the fission mechanisms of these two symmetric fissions are different.