Research Group for Nuclear Chemistry of Superheavy Elements

Studies of chemical and nuclear properties of the elements at the uppermost end of the periodic table are 
being performed. The elements heavier than fermium with atomic number 100 must be produced at accelerators 
using reactions of heavy ions with heavy target materials. Both the half-lives and production rates of the 
nuclides of the still heavier elements are rapidly decreasing. Consequently, they are usually available in 
very small quantities, only an atom at a time. We are devising rapid and very efficient chemical separation 
apparatus based on chromatographic and electrochemical methods, and are investigating chemical properties 
of the heaviest elements with single atoms using the developed apparatus. Nuclear properties of the heaviest 
elements are also being studied to explore nuclear shell structure in the region of the heaviest nuclei and 
to clarify mass division mechanism in nuclear fission of heavy nuclei.

   Yuichiro Nagame       Group Leader
   Kazuaki Tsukada       Assistant Principal Researcher
   Masato Asai           Assistant Principal Researcher
   Tetsuya Sato          Assistant Principal Researcher
   Atsushi Toyoshima     Senior Post-Doctoral Fellow
   Nozomi Sato           Post-Doctoral Fellow
   Li Zijie              Post-Doctoral Fellow
   Takahiro Kikuchi      Fellow of Advanced Science  
   Liang Xiaohu

Member of Nuclear chemistry of superheavy elements group

 Selected publications

  1.  "Oxidation of element 102, nobelium, with flow electrolytic column chromatography on 
     an atom-at-a-time scale" 
   A. Toyoshima, Y. Kasamatsu, K. Tsukada, M. Asai, Y. Kitatsuji, Y. Ishii, H. Toume, I. Nishinaka, 
     H. Haba, K. Ooe, W. Sato, A. Shinohara, K. Akiyama, and Y. Nagame, 
     J. Am. Chem. Soc. 131, 9180-9181 (2009).

 2. "Spectroscopy of 257Rf"
   J. Qian, A. Heinz, T.L. Khoo, R.V.F. Janssens, D. Peterson, D. Seweryniak, I. Ahmad, M. Asai, 
     B.B. Back, M.P. Carpenter, A.B. Garnsworthy, J.P. Greene, A.A. Hecht, C.L. Liang, F.G. Kondev, 
     T. Lauritsen, C.J. Lister, A.P. Robinson, G. Savard, R.Scott, R. Vondrasek, X. Wang, R. Winkler, 
     and S. Zhu, 
     Phys. Rev. C 79, 064319-1-13 (2009).

  3.  "Chloride complexation of Zr and Hf in HCl investigated by extended x-ray absorption fine structure 
     spectroscopy: Toward characterization of chloride complexation of element 104, rutherfordium (Rf)" 
     H. Haba, K. Akiyama, K. Tsukada, M. Asai, A. Toyoshima, T. Yaita, M. Hirata, and Y. Nagame, 
   Bull. Chem. Soc. Jpn. 82, 698-703 (2009).

  4.  "Decay properties of 266Bh and 262Db produced in the 248Cm + 23Na reaction" 
   K. Morita, K. Morimoto, D. Kaji, H. Haba, K. Ozeki, Y. Kudou, N. Sato, T. Sumita, A. Yoneda, 
     T. Ichikawa,, Y. Fujimori, S. Goto, E. Ideguchi, Y. Kasamatsu, K. Katori, Y. Komori, H. Koura, 
     H. Kudo, K. Ooe, A. Ozawa, F. Tokanai, K. Tsukada, T. Yamaguchi, and A. Yoshida, 
     J. Phys. Soc. Jpn. 78, 064201-1-6 (2009).

  5. "Cross section limits for the 248Cm(26Mg, 4-5n)268,269Hs reactions" 
   J. Dovrak, W. Bruchle, Ch. E. Dullmann, Z. Dvorakova, K. Eberhardt, R. Eichler, E. Jager, Y. Nagame, 
     Z. Qin, M. Schadel, B. Schausten, E. Schimpf, R. Schuber, A. Semchenkov, P. Thorler, A. Turler, 
     M. Wegrzecki, and A. Yakushev, 
     Phys. Rev. C 79, 037602-1-4 (2009).

  6. "Adsorption of Db and its homologues Nb and Ta, and the pseudo-homologue Pa on anion-exchange 
     resin in HF solution" 
     Tsukada, K., Haba, H., Asai, M., Toyoshima, A., Akiyama, K., Kasamatsu,Y., Nishinaka, I., 
     Ichikawa, S., Yasuda, K., Miyamoto, Y., Hashimoto, K., Nagame, Y., Goto, S., Kudo, H., 
     Sato, W., Shinohara, A., Oura, Y., Sueki, K., Kikunaga, H., Kinoshita, N., Yokoyama, A., 
     Schadel, M., Bruchle, W. and Kratz, J. V., 
     Radiochim. Acta 97, 83-89 (2009).

  7. "Adsorption of Nb, Ta and Pa on anion-exchanger in HF and HF/HNO3 solution - Model 
     experiments for the chemical study of Db -" 
   Kasamatsu, Y., Toyoshima, A., Haba, H., Toume, H., Tsukada,K., Akiyama, K., Yoshimura, T., 
     and Nagame, Y., 
     J. Radioanal. Nucl. Chem. 279, 371-376 (2009).

  8. "Kπ= 8- isomers and Kπ= 2- octupole vibrations in N = 150 shell-stabilized isotones" 
   A. P. Robinson, T. L. Khoo, I. Ahmad, S. K. Tandel, F. G. Kondev, T. Nakatsukasa, D. Seweryniak, 
     M. Asai, B. B. Back, M. P. Carpenter, P. Chowdhury, C. N. Davids, S. Eeckhaudt, J. P. Greene, 
     P. T. Greeless, S. Gros, A. Heinz, R.-D. Herzberg, R. V. F. Janssen, G. D. Jones, T. Lauritsen, 
     C. J. Lister, D. Peterson, J. Qian, U. S. Tandel, X. Wang, and S. Zhu, 
     Phys. Rev. C 78, 034308-1-6 (2008).

  9.  "Observation of high-j quasiparticle states in 249Cm by in-beam γ-ray spectroscopy 
     using heavy-ion transfer reactions" 
   T. Ishii, H. Makii, M. Asai, K. Tsukada, A. Toyoshima, M. Matsuda, A. Makishima, S. Shigematsu, 
     J. Kaneko, T. Shizuma, H. Toume, I. Hossain, T. Kohno, and M. Ogawa, 
     Phys. Rev. C 78, 054309-1-11 (2008).

  10. "Development of an electrochemistry apparatus for the heaviest elements" 
    Toyoshima, A., Kasamatsu, Y., Kitatsuji, Y., Tsukada, K., Haba, H., Shinohara, A., and Nagame, 
     Y., Radiochim. Acta 96, 323-326 (2008).

  11. "Hexafluoro complex of rutherfordium in mixed HF/HNO3 solutions" 
   Toyoshima, A., Haba, H., Tsukada, K., Asai, A., Akiyama, K., Goto, S., Ishii, Y., Nishinaka, I., 
     Sato, T. k., Nagame, Y., Sato, W., Tani, Y., Hasegawa, H., Matsuo, K., Saika, D., Kitamoto, Y., 
     Shinohara, A., Ito, M., Saito, J., Kudo, H., Yokoyama, A., Sakama, M., Sueki, K., Oura, Y., 
     Nakahara, H., Schadel, M., Bruchle, W., and Kratz, J. V., 
     Radiochim. Acta 96, 125-132 (2008).

  12.  "Fluoride complexation of element 104, rutherfordium (Rf), investigated by cation-exchange 
   Ishii, Y., Toyoshima, A., Tsukada, K., Asai, M., Toume, H., Nishinaka, I., Nagame,Y., 
      Miyashita, S., Mori, T., Suganuma, H., Haba, H., Sakamaki, M., Goto, S., Kudo, H., Akiyama, K., 
      Oura, Y., Nakahara, H., Tashiro, Y., Shinohara, A., Schadel, M., Bruchle, W.,Pershina, V., 
      and Kratz, J. V., 
   Chem. Lett. 37, 288-289 (2008).

 13.  "Effects of nuclear orientation on the mass distribution of fission fragments in the reaction 
      of 36S + 238U" 
   Nishio, K., Ikezoe, H., Mitsuoka, S., Nishinaka, I., Nagame, Y., Watanabe, Y., Ohtsuki, T., 
      Hirose, K., and Hofmann, S., 
      Phys. Rev. C 77, 064607-1-5 (2008).

 14.  "Observation of the 3n evaporation channel in the complete hot-fusion reaction 26Mg + 248Cm 
      leading to the new superheavy nuclide 271Hs" 
      Dovrak, J., Bruchle, W., Chelnokov, M., Dullmann, Ch. E., Dvorakova, Z., Eberhardt, K., Jager, E., 
      Krucken, R., Kuznetsov, A., Nagame, Y., Nebel, F., Nishio, K., Perego, R., Qin, Z., Schadel, M., 
      Schausten, B., Schimpf, E., Schuber, R., Semchenkov, A., Thorler, P., Turler, A., Wegrzecki, M., 
      Wierczinski, B., Yakushev, A., and Yeremin, A., 
      Phys. Rev. Lett. 100, 132503-1-4 (2008).

  15.  "Production and Chemsitry of Transactinide Elements" 
      Nagame, Y. and Haba, H., 
      in Radiochemistry and Nuclear Chemistry, Ed. Sandor Nagy, in Encyclopedia of Life Support Systems 
      (EOLSS), Developed under the Auspices of the UNESCO, Eolss Publishers, Oxford , 
      UK, 2007, [].

  16.  "Anion-exchange behavior of Nb, Ta, and Pa as homologues of Db in HF/HNO3 solutions" 
      Kasamatsu, Y., Toyoshima, A., Toume, H., Tsukada, K., Haba, H., and Nagame, Y., 
      J. Nucl. Radiochem. Sci. 8, 69-72 (2007).

  17.  "Extraction behavior of rutherfordium into tributylphosphate from hydrochloric acid" 
      Haba, H., Tsukada, K., Asai, M., Toyoshima, A., Ishii, Y., Toume, H., Sato, T., Nishinaka, I., 
      Ichikawa, T., Ichikawa, S., Nagame, Y., Sato, W., Matsuo, K., Kitamoto, Y., Tashiro, Y., 
      Shinohara, A., Saito, J., Ito, M., Ikezawa, M., Sakamaki, M., Goto, S., Kudo, H., Kikunaga, H., 
      Arai, M., Kamataki, S., Yokoyama, A., Akiyama, K., Sueki, K., Oura, Y., Schadel, M., Bruchle, W. 
      and Kratz, J. V., 
      Radiochim. Acta 95, 1-6 (2007).

  18.  "Z dependence of the N = 152 deformed shell gap: In beam γ-ray spectroscopy of neutron-rich 
      Makii, H., Ishii, T., Asai, M., Tsukada, K., Toyoshima, A., Matsuda, M., Makishima, A., Kaneko, J., 
      Toume, H., Ichikawa, S., Shigematsu, S., Kohno, T., and Ogawa, M., 
      Phys. Rev. C 76, 061301(R)-1-5 (2007).

  19.  "Doubly magic 270108Hs162"
      Dovrak, J., Bruchle, W., Chelnokov, M., Dressler, R., Dullmann, Ch. E., Eberhardt, K., Gorshokov, V., 
      Jager, E., Krucken, R., Kuznetsov, A., Nagame, Y., Nebel, F., Novackova, Z., Qin, Z., Schadel, M., 
      Schausten, B., Schimpf, E., Semchenkov, A., Thorle, P., Turler, A., Wegrzecki, M., Wierczinski, B., 
      Yakushev, A. and Yeremin, A., 
      Phys. Rev. Lett. 97, 242501-1-4 (2006).

  20.  "Measurement of evaporation residue cross-sections of the reaction 30Si + 238U at subbarrier 
     Nishio, K., Hofmann, S., Hessberger, F. P., Ackermann, D., Antalic, S., Comas, V. F., Gan, Z., 
     Heinz, S., Heredia, J. A., Ikezoe, H., Khuyagbaatar, J., Kindler, B., Kojouharov, I., Kuusiniemi, P., 
     Lommel, B., Mann, R., Mazzocco, M., Mitsuoka, S., Nagame, Y., Ohtsuki, T., Popeko, A. G., Saro, S., 
     Schott, H. J., Sulignano, B., Svirikhin, A., Tsukada, K., Tsuruta, K. and Yeremin, 
     A. V., Eur. Phys. J. A 29, 281-287 (2006).