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Journal Articles

Investigation of the $$Delta$$$$n$$ = 0 selection rule in Gamow-Teller transitions; The $$beta$$-decay of $$^{207}$$Hg

Berry, T. A.*; Podoly$'a$k, Zs.*; Carroll, R. J.*; Lic$u{a}$, R.*; Grawe, H.*; Timofeyuk, N. K.*; Alexander, T.*; Andreyev, A. N.; Ansari, S.*; Borge, M. J. G.*; et al.

Physics Letters B, 793, p.271 - 275, 2019/06

 Times Cited Count:2 Percentile:48.28(Astronomy & Astrophysics)

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

 Times Cited Count:15 Percentile:23.53(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

First ionization potential of the heaviest actinide lawrencium, element 103

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Stora, T.*; Sato, Nozomi*; Kaneya, Yusuke; Tsukada, Kazuaki; D$"u$llmann, C. E.*; Eberhardt, K.*; Eliav, E.*; et al.

EPJ Web of Conferences, 131, p.05001_1 - 05001_6, 2016/12

 Times Cited Count:0 Percentile:100

Ionization efficiency in a surface ionization process depends on the first ionization potential of the atom. Based on the dependence, the ionization potential of the atom can be determined. We measured ionization efficiencies of fermium, einsteinium, mendelevium, and lawrencium by using a newly developed gas-jet coupled surface ion-source. The ionization potential of the elements have not been determined so far due to their low production rates and/or their short half-lives. Based on a relationship between the ionization efficiency and the ionization potential obtained via measurements of short-lived lanthanide isotopes, the ionization potentials of these actinide elements have been successfully determined.

Journal Articles

Measurement of the first ionization potential of lawrencium, element 103

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Stora, T.*; Sato, Nozomi; Kaneya, Yusuke; Tsukada, Kazuaki; D$"u$llmann, Ch. E.*; Eberhardt, K.*; Eliav, E.*; et al.

Nature, 520(7546), p.209 - 211, 2015/04

 Times Cited Count:86 Percentile:1.7(Multidisciplinary Sciences)

Ionization efficiency in a surface ionization process depends on the first ionization potential of the atom. Based on the dependence, the ionization potential of the atom can be determined. We successfully measured ionization efficiencies of lawrencium (Lr, $$Z$$=103) using a gas-jet coupled surface ion-source. The ionization potential of Lr has not been determined owing to its low production rate and its short half-life. Based on a relationship between the ionization efficiency and the ionization potential obtained via measurements of short-lived lanthanide isotopes, the ionization potential of Lr was determined.

Journal Articles

Development of a He/CdI$$_{2}$$ gas-jet system coupled to a surface-ionization type ion-source in JAEA-ISOL; towards determination of the first ionization potential of Lr (Z = 103)

Sato, Tetsuya; Asai, Masato; Sato, Nozomi; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro*; Miyashita, Sunao*; Kaneya, Yusuke; Osa, Akihiko; Sch$"a$del, M.; et al.

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1253 - 1257, 2015/02

 Times Cited Count:7 Percentile:35.04(Chemistry, Analytical)

We have developed a surface-ionization ion-source coupled to the He/CdI$$_2$$ gas-jet transport system for the Isotope Separator On-Line (ISOL) at the JAEA tandem accelerator for experimental determination of the first ionization potential of lawrencium (Lr, $$Z = 103$$). We performed to ionize a short-lived Lr isotope and various lanthanide isotopes. We successfully observed mass-separated ions of $$^{256}$$Lr by using our present system at the first time. The first ionization potential of Lr was evaluated based on a correlation between of effective ionization potential and ionization efficiency of short-lived lanthanide isotopes in our system.

Journal Articles

First successful ionization of Lr (Z=103) by a surface-ionization technique

Sato, Tetsuya; Sato, Nozomi; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro; Miyashita, Sunao; Sch$"a$del, M.; Kaneya, Yusuke*; Nagame, Yuichiro; et al.

Review of Scientific Instruments, 84(2), p.023304_1 - 023304_5, 2013/02

 Times Cited Count:14 Percentile:37.3(Instruments & Instrumentation)

We have developed the surface ion-source coupled to the He/CdI$$_2$$ gas-jet transport system to measure the ionization potential of Lr atatom-at-a-time conditions. We successfully ionized and mass-separated for the first time $$^{256}$$Lr ions by applying the present ion-source and the ISOL technique. The ionization efficiencies of Lr were estimated to be approximately 42% and 24% at 2600 K on Re and Ta surfaces, respectively. These values were higher than those of Lu in all of ionization condition. The results indicate that the ionization potential of Lr would be lower than that of Lu, 5.4 eV. Therefore, it is concluded that the surface ion-source is a promising apparatus tomeasure the first ionization potential of Lr. Using the present system, determination of the ionization potential of Lr is being performed.

Oral presentation

Ionization potential measurement of lawrencium (Lr, Z=103) by the surface ionization method

Sato, Tetsuya; Sato, Nozomi; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro; Miyashita, Sunao; Nagame, Yuichiro; Sch$"a$del, M.; Osa, Akihiko; et al.

no journal, , 

In order to determine the IP of lawrencium (Lr, Z = 103) by a surface ionization technique, we have developed a thermal ion source coupled to a gas-jet transport system for an Isotope Separator On-Line (ISOL) at the JAEA tandem accelerator facility. We measured ionization efficiencies of the short-lived Lr isotope, $$^{256}$$Lr ($$T_{1/2}$$ = 27 s), and the Lu isotope, $$^{164}$$Lu ($$T_{1/2}$$ = 3.1 min), using the ion source. The mass-separated $$^{256}$$Lr ions were successfully observed. Ionization efficiencies on the Re surface at 2600 K of Lr and Lu were evaluated to be 42% and 20%, respectively. Those experimental results suggests that the ionization potential of Lr could be lower than that of Lu as expected from theoretical calculation.

Oral presentation

Development of a gas-jet coupled surface ion source of ISOL for measurement of the first ionization potential of Lr, 2

Kaneya, Yusuke*; Sato, Tetsuya; Sonoda, Nozomi; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro; Miyashita, Sunao; Nagame, Yuichiro; Sch$"a$del, M.; et al.

no journal, , 

In order to determine the first ionization energy of lawrencium (Lr, ${it Z}$ = 103), we have developed a new surface ionization ion source coupled to a gas-jet transport system in ISOL (Isotopes Separator On-Line) at the JAEA tandem accelerator facility. On-line experiments with short-lived lanthanide isotopes using the new ion-source were performed. It would be confirmed that the ionization energy of lanthanide which boiling point is up to 3000$$^{circ}$$C can be determined.

Oral presentation

Development of a surface-ionization type ion-source at the JAEA-ISOL set-up for a measurement of the first ionization potential of Lr (Z=103)

Sato, Tetsuya; Sonoda, Nozomi; Kaneya, Yusuke*; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro; Miyashita, Sunao; Osa, Akihiko; Ichikawa, Shinichi; et al.

no journal, , 

In order to determine the first ionization potential of lawrencium (Lr, Z=103), we have developed an appropriate surface-ionization type ion source as a part of the JAEA-ISOL setup, which is coupled to a He/CdI$$_2$$ gas-jet transport system. The new ion source is an improved version based on our previously used ion source, which already had a good ionization efficiencies for lanthanide. To achieve higher ionization efficiencies of low volatility elements like Lr, an additional filament was newly installed. We report, here, on the development and performance of our new gas-jet coupled surface-ionization ion source, and on the first successful ionization and mass separation of 27-s $$^{256}$$Lr produced in the $$^{249}$$Cf + $$^{11}$$B reaction.

Oral presentation

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

Sato, Tetsuya; Kaneya, Yusuke*; Sonoda, Nozomi; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro; Miyashita, Sunao; Nagame, Yuichiro; Sch$"a$del, M.; et al.

no journal, , 

In order to determine the first ionization potential (IP) of lawrencium (Lr, Z=103), we have developed a surface ionization type ion-source coupled to a He/CdI$$_2$$ gas-jet transport system for the JAEA-ISOL. We measured ionization efficiencies of $$^{256}$$Lr and various short-lived lanthanide isotopes by applying the ion-source. We successfully ionized and mass-separated for the first time $$^{256}$$Lr ions. From a correlation between the IPs and ionization efficiencies of the short-lived lanthanide isotopes, we estimated the IP of Lr in this work.

Oral presentation

Development of surface ionization method for determination of the first ionization potentials of heavy actinides

Kaneya, Yusuke*; Sato, Tetsuya; Sonoda, Nozomi; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro; Miyashita, Sunao; Nagame, Yuichiro; Sch$"a$del, M.; et al.

no journal, , 

We have developed a surface ionization ion-source as part of the JAEA-ISOL that is coupled to a He/CdI$$_{2}$$ gas-jet transport system to determine the first ionization potential (IP) of heavy actinides. Ionization efficiencies of various short-lived lanthanide isotopes produced in the nuclear reactions were measured with the present system. Obtained results demonstrate that the developed ion-source could be applicable to the measurement of the IP of heavy actinides.

Oral presentation

The First successful ionization of Lr ($$Z$$=103) by a surface ionization technique

Sato, Tetsuya; Asai, Masato; Sato, Nozomi; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro*; Miyashita, Sunao*; Sch$"a$del, M.; Kaneya, Yusuke; Nagame, Yuichiro; et al.

no journal, , 

We have newly developed a surface ionization ion-source coupled to a He/CdI$$_2$$ gas-jet transport system for JAEA-ISOL in order to determine the first ionization potential of the heaviest actinide element, lawrencium ($$Lr$$, $$Z$$=103). In this work, we successfully ionized $$^{256}$$Lr produced in the reaction of $$^{249}$$Cf and $$^{11}$$B with the ionization efficiency of about 37% with the present apparatus. And we evaluated the first ionization potential of Lr from a correlation between effective ionization potentials and ionization efficiencies of short-lived lanthanide isotopes for the first time.

Oral presentation

Development of surface ionization ion-source for determination of the first ionization potential of heavy actinides

Kaneya, Yusuke; Sato, Tetsuya; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Miyashita, Sunao*; Nagame, Yuichiro; Sch$"a$del, M.; Sato, Nozomi; Oe, Kazuhiro*; et al.

no journal, , 

We have developed a surface ionization ion-source as part of the JAEA-ISOL that is coupled to a He/CdI$$_{2}$$ gas-jet transport system to determine the first ionization potential (IP) of heavy actinides. Separation efficiencies of various short-lived lanthanide isotopes as homologs of actinides that were produced in nuclear reactions were measured with the present system. Obtained results demonstrate that the developed ion-source would be applicable to a measurement of the IP of heavy actinides.

Oral presentation

Ionization behavior of lawrencium (Lr, $$Z = 103$$) on surface ionization process

Sato, Tetsuya; Asai, Masato; Sato, Nozomi; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro*; Miyashita, Sunao; Sch$"a$del, M.; Kaneya, Yusuke; Nagame, Yuichiro; et al.

no journal, , 

In order to determine the first ionization potential of lawrencium (Lr, $$Z = 103$$), we have developed a surface ionization type ion-source coupled to a He/CdI$$_2$$ gas-jet transport system for an Isotope Separator On-Line (ISOL) of the JAEA tandem accelerator experimental facility. We measured ionization efficiencies of short-lived Lr isotope and various short-lived lanthanide isotopes with our present system. We successfully ionized and mass-separated $$^{256}$$Lr ions for the first time and evaluated the first ionization potential of Lr based on a correlation between an effective ionization potential and ionization efficiencies of the lanthanide isotopes.

Oral presentation

Measurement of the first ionization potential of Lr by surface ionization technique

Sato, Tetsuya; Asai, Masato; Sato, Nozomi; Kaneya, Yusuke; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro*; Miyashita, Sunao*; Nagame, Yuichiro; Sch$"a$del, M.; et al.

no journal, , 

The first ionization potential of the heaviest actinide elements have not been measured until today owing to short half-lives and low production rates of the isotopes. Based on the surface ionization technique, we performed a measurement of the ionization potential of the heaviest actinide element, lawrencium (Lr, $$Z=103$$), by using a newly developed surface ion-source installed to the JAEA-ISOL(Isotope Separator On-Line) at the JAEA tandem accelerator facility. We report on an evaluation of the IP value of Lr based on comparison of ionization behavior of short-lived lanthanide isotopes and $$^{256}$$Lr on Ta surface at several temperature in the ion-source.

Oral presentation

Measurement of the first ionization potentials of short-lived lanthanides using a surface ionization method

Kaneya, Yusuke; Sato, Tetsuya; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Nagame, Yuichiro; Sch$"a$del, M.; Sato, Nozomi; Oe, Kazuhiro*; Miyashita, Sunao*; et al.

no journal, , 

Oral presentation

The First successful determination of the first ionization potential of lawrencium (Lr, $$Z = 103$$)

Sato, Tetsuya; Asai, Masato; Sato, Nozomi; Kaneya, Yusuke; Toyoshima, Atsushi; Miyashita, Sunao*; Oe, Kazuhiro*; Osa, Akihiko; Ichikawa, Shinichi; Nagame, Yuichiro; et al.

no journal, , 

The first ionization potential of the heaviest actinide elements have not been measured until today owing to short half-lives and low production rate of the isotopes. Based on the surface ionization technique, we performed a measurement of the ionization potential of the heaviest actinide element, lawrencium (Lr, $$Z = 103$$), by using a newly developed surface ion-source installed to the JAEA-ISOL (Isotope Separator On-Line) at the JAEA tandem accelerator facility. We report on an evaluation of the IP value of Lr based on comparison of ionization behavior of short-lived lanthanide isotopes and $$^{256}$$Lr on Ta surface at several temperature in the ion-source.

Oral presentation

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

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

no journal, , 

In order to determine the IP of the heavy elements, we have developed a novel measurement method based on a surface ionization technique by using a surface ionization ion source coupled to a He/CdI$$_2$$ gas-jet transport system for an Isotope Separator On-Line (ISOL) at the JAEA tandem accelerator facility. In this work, we have determined IP value of No by using the method. In a surface ionization process, an ionization efficiency of an atom depends on its IP. To obtain a relationship between IP and ionization efficiency in present system, we measured ionization efficiencies of various short-lived isotopes. Ionization efficiency of $$^{257}$$No produced in the $$^{248}$$Cm($$^{13}$$C, 4n) reaction was also measured. Measured ionization efficiency of $$^{257}$$No was 0.8%, which yields IP value of No to be 6.6 eV. This value is in a good agreement with the value which has been evaluated by extrapolation from those of the lighter actinide elements, 6.65 eV.

Oral presentation

The First ionization potential measurement of lawrencium (Lr, $$Z$$ = 103)

Sato, Tetsuya; Asai, Masato; Kaneya, Yusuke; Tsukada, Kazuaki; Toyoshima, Atsushi; Miyashita, Sunao*; Oe, Kazuhiro*; Osa, Akihiko; Ichikawa, Shinichi; Nagame, Yuichiro; et al.

no journal, , 

The first ionization potentials of the heaviest actinide elements have not been measured until today owing to short half-lives and low production rates of the isotopes. Based on the surface ionization technique, we performed a measurement of the ionization potential of the heaviest actinide element, lawrencium (Lr, $$Z$$ = 103), by using a newly developed surface ion-source installed to the JAEA-ISOL (Isotope Separator On-Line) at the JAEA tandem accelerator facility. We report on an evaluation of the IP value of Lr based on comparison of ionization behavior of $$^{256}$$Lr with that of short-lived lanthanide isotopes on Ta surface at several temperature.

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.

26 (Records 1-20 displayed on this page)