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Journal Articles

First online operation of TRIGA-TRAP

Grund, J.*; Asai, Masato; Blaum, K.*; Block, M.*; Chenmarev, S.*; D$"u$llmann, Ch. E.*; Eberhardt, K.*; Lohse, S.*; Nagame, Yuichiro*; Nagy, Sz.*; et al.

Nuclear Instruments and Methods in Physics Research A, 972, p.164013_1 - 164013_8, 2020/08

https://doi.org/10.1016/j.nima.2020.164013
 Times Cited Count：6 Percentile：60.71(Instruments & Instrumentation)

We report on the successful coupling of the Penning-trap mass spectrometry setup TRIGA-TRAP to the research reactor TRIGA Mainz. This offers the possibility to perform direct high-precision mass measurements of short-lived nuclei produced in neutron-induced fission of a $$^{235}$$U target located near the reactor core. An aerosol-based gas-jet system is used for efficient transport of short-lived neutron-rich nuclei from the target chamber to a surface ion source. In conjunction with new ion optics and extended beam monitoring capabilities, the experimental setup has been fully commissioned. The design of the surface ion source, efficiency studies and first results are presented.

Journal Articles

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
 Times Cited Count：27 Percentile：69.46(Chemistry, Multidisciplinary)

The first ionization potential (IP$$_1$$) yields information on valence electronic structure of an atom. IP$$_1$$ 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$$_1$$ 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$$_1$$ among the actinide elements owing to its full-filled 5f and the 7s orbitals. In the present study, we have successfully determined IP$$_1$$ 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$$_1$$ value of heavy actinoids would increase monotonically with filling electrons up in the 5f orbital like heavy lanthanoids.

Journal Articles

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.

Journal Articles

The First ionization potential of element 103 successfully measured for the first time substantiated that lawrencium is the last member of actinide series

Sato, Tetsuya

Isotope News, (740), p.16 - 19, 2015/12

http://www.jrias.or.jp/books/pdf/201512_TRACER_SATO.pdf

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.

Journal Articles

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$$Sigma$$, 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.

Journal Articles

Measurement of the first ionization energy of lawrencium (Z = 103) by surface ionization technique

Sato, Tetsuya

Hosha Kagaku, (32), p.34 - 41, 2015/09

In the surface ionization process, an ionization efficiency depends on the first ionization potential of the atom of the element. The ionization potential can be estimated by using the relationship. This method has been developed in order to determine the first ionization potential of lawrencium (Lr, element 103). The value of the ionization potential of Lr have not been measured experimentally due to its low production rate and short half-life. The surface-ionization method is described in detail in this paper.

Journal Articles

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.

Journal Articles

Production of endohedral $$^{133}$$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
 Times Cited Count：1 Percentile：11.32(Chemistry, Analytical)

no abstracts in English

Journal Articles

$$alpha$$-decays of neutron-deficient americium isotopes

Sakama, Minoru*; Asai, Masato; Tsukada, Kazuaki; Ichikawa, Shinichi; Nishinaka, Ichiro; Nagame, Yuichiro; Haba, Hiromitsu*; Goto, Shinichi*; Shibata, Michihiro*; Kawade, Kiyoshi*; et al.

Physical Review C, 69(1), p.014308_1 - 014308_11, 2004/01

https://doi.org/10.1103/PhysRevC.69.014308
 Times Cited Count：21 Percentile：73.68(Physics, Nuclear)

no abstracts in English

Journal Articles

Ion source development for the JAERI on-line isotope separator

Ichikawa, Shinichi; Osa, Akihiko; Matsuda, Makoto; Tsukada, Kazuaki; Asai, Masato; Nagame, Yuichiro; Jeong, S.-C.*; Katayama, Ichiro*

Nuclear Instruments and Methods in Physics Research B, 204, p.372 - 376, 2003/05

https://doi.org/10.1016/S0168-583X(02)01976-6
 Times Cited Count：17 Percentile：72.74(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Production of endohedral $$^{133}$$Xe-fullerene by ion implantation

Watanabe, Satoshi; Ishioka, Noriko; Sekine, Toshiaki; Osa, Akihiko; Koizumi, Mitsuo; Shimomura, Haruhiko*; Yoshikawa, K.*; Muramatsu, Hisakazu*

Journal of Radioanalytical and Nuclear Chemistry, 255(3), p.495 - 498, 2003/03

https://doi.org/10.1023/A:1022524214082
 Times Cited Count：11 Percentile：59.38(Chemistry, Analytical)

no abstracts in English

Journal Articles

Production of a radioactive endovascular stents by implantation of $$^{133}$$Xe ions

Watanabe, Satoshi; Osa, Akihiko; Sekine, Toshiaki; Ishioka, Noriko; Koizumi, Mitsuo; Kojima, Takuji; Hasegawa, A.*; Yoshii, M.*; Okamoto, E.*; Aoyagi, K.*; et al.

Applied Radiation and Isotopes, 51(2), p.197 - 202, 1999/08

https://doi.org/10.1016/S0969-8043(98)00180-8
 Times Cited Count：7 Percentile：49.7(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Q$$_{EC}$$ measurements of $$^{124,125,127-130}$$La

Kojima, Yasuaki*; Asai, Masato*; Osa, Akihiko; Koizumi, Mitsuo; Sekine, Toshiaki; Shibata, M.*; *; Kawade, Kiyoshi*; Tachibana, Takahiro*

Journal of the Physical Society of Japan, 67(10), p.3405 - 3413, 1998/10

https://doi.org/10.1143/JPSJ.67.3405
 Times Cited Count：10 Percentile：58.6(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Status report of the TIARA-ISOL

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

"Fuanteikaku No Rikogaku Oyobi Kaku Keisokuho(II)" Ni Kansuru Semmon Kenkyukai Hokokusho, 0, p.28 - 30, 1997/00

no abstracts in English

Oral presentation

Measurement of the first ionization energy of nobelium (No, $$Z$$ = 102)

Sato, Tetsuya; Asai, Masato; Kaneya, Yusuke; Tsukada, Kazuaki; Toyoshima, Atsushi; Takeda, Shinsaku; Mitsukai, Akina*; Nagame, Yuichiro; Ichikawa, Shinichi; Makii, Hiroyuki; et al.

no journal, , 

We successfully determined the first ionization energy (IE) of nobelium (No, $$Z$$ = 102) using a short-lived No isotope, $$^{257}$$No produced in the$$^{248}$$Cm($$^{13}$$C, 4n) reaction, based on the IE dependence of the ionization efficiency in a surface ionization process. The IE value of No was evaluated to be 6.6 eV. This value is in a good agreement with the value which has been estimated by an extrapolation from those of the lighter actinide elements, 6.65 eV.

Oral presentation

First ionization potential measurements of heavy actinides, lawrencium and nobelium

Sato, Tetsuya

no journal, , 

The experimental determination of the first ionization potential (IP) yields information on the electronic structure of the element. We successfully ionized and mass-separated $$^{257}$$No and $$^{256}$$Lr with efficiencies ($$I_{rm eff}$$) of (0.5 $$pm$$ 0.1)% and (36 $$pm$$ 7)% at 2800 K, respectively. From these $$I_{rm eff}$$ values, IP values of No and Lr were determined based on the relationship between $$I_{rm eff}$$ and IP. Our values are in good agreement with the predicted ones by theoretical calculations.

Oral presentation

First ionization energy measurements of heaviest actinides, lawrencium and nobelium

Sato, Tetsuya

no journal, , 

We measured the first ionization energy (IE$$_1$$) of nobelium (No, Z = 102) and lawrencium (Lr, Z =103) by exploiting the dependence of the ionization efficiency ($$I_{rm eff}$$) on the IE$$_1$$ in a surface ionization process. The isotopes $$^{257}$$No ($$T_{1/2}$$ = 24.5s) and $$^{256}$$Lr ($$T_{1/2}$$ = 27 s), produced in the reaction $$^{248}$$Cm ($$^{13}$$C, 4n) and $$^{249}$$Cf ($$^{11}$$B, 4n), respectively, were used for studying their ionization. The reaction products recoiling from the targets were transported to a surface ion-source by a He/CdI$$_2$$ gas-jet transport system. The products ionized in the ion-source were mass-separated with JAEA-ISOL. The number of ions collected at the end of the ISOL was determined by $$alpha$$-particle measurements and was used to evaluate $$I_{rm eff}$$ values. With the present system, we successfully ionized and mass-separated $$^{257}$$No and $$^{256}$$Lr with efficiencies of (0.5 $$pm$$ 0.1)% and (36 $$pm$$ 7)% at 2800 K, respectively. From these $$I_{rm eff}$$ values, IE$$_1$$ values of No and Lr were determined based on the relationship between $$I_{rm eff}$$ and IE$$_1$$. Our values are in good agreement with the predicted ones by theoretical calculations.

Oral presentation

First ionization potentials of heavy actinides

Sato, Tetsuya; Asai, Masato; Kaneya, Yusuke*; Tsukada, Kazuaki; Toyoshima, Atsushi; Mitsukai, Akina*; Takeda, Shinsaku*; Vascon, A.*; Sakama, Minoru*; Sato, Daisuke*; et al.

no journal, , 

The first ionization potential (IP$$_1$$) yields information on valence electronic structure of an atom. IP$$_1$$ 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$$_1$$ 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$$_1$$ among the actinide elements owing to its full-filled 5f and the 7s orbitals. In the present study, we have successfully determined IP$$_1$$ 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$$_1$$ value of heavy actinoids would increase monotonically with filling electrons up in the 5f orbital like heavy lanthanoids.

Oral presentation

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]$$5f^{14}7s^27p_{1/2}$$, which is different from that of the lanthanide homolog Lu [Xe]$$4f^{14}6s^25d$$ 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 $$^{256}$$Lr, which was produced in the reaction of $$^{249}$$Cf($$^{11}$$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 $$^{256}$$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.

Oral presentation

Discrepancy in the periodic table appears at element 103; The Periodic table of elements might be restructured

Sato, Tetsuya

no journal, , 

The first ionization potential (IP$$_1$$) of element 103, lawrencium (Lr), has been successfully determined for the first time by using a newly developed method based on a surface ionization process. The measured IP$$_1$$ value is 4.96 $$pm$$ 0.08 eV. This value is the smallest among those of actinide elements and is in excellent agreement with the value of 4.963(15) eV predicted by state-of-the-art relativistic calculations also performed in this work. Our results strongly support that the Lr atom has an electronic configuration of [Rn]$$7s^25f^{14}7p_{1/2}$$, which is influenced by strong relativistic effects. The present work opens the way for studies on atomic properties of heavy elements with atomic number $$Z > 100$$. Moreover, the present achievement has triggered a controversy on the position of lutetium (Lu) and Lr in the Periodic Table of Elements.

24 (Records 1-20 displayed on this page)