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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

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

$$alpha$$-decay properties of $$^{200,202}$$Fr

Ghys, L.*; Andreyev, A. N.; Huyse, M.*; Van Duppen, P.*; Antalic, S.*; Barzakh, A.*; Capponi, L.*; Cocolios, T. E.*; Cubiss, J.*; Derkx, X.*; et al.

Physical Review C, 100(5), p.054310_1 - 054310_13, 2019/11

 Times Cited Count:4 Percentile:22.15(Physics, Nuclear)

Journal Articles

Nuclear and chemical characterization of heavy actinides

Nagame, Yuichiro

Radiochimica Acta, 107(9-11), p.803 - 819, 2019/09

 Times Cited Count:0 Percentile:100(Chemistry, Inorganic & Nuclear)

Journal Articles

From SRAFAP to ARCA and AIDA; Developments and implementation of automated aqueous-phase rapid chemistry apparatuses for heavy actinides and transactinides

Sch$"a$del, M.*; Nagame, Yuichiro

Radiochimica Acta, 107(7), p.561 - 585, 2019/07

 Times Cited Count:1 Percentile:53.3(Chemistry, Inorganic & Nuclear)

Journal Articles

Optimization of an isothermal gas-chromatographic setup for the chemical exploration of dubnium (Db, Z = 105) oxychlorides

Chiera, N. M.; Sato, Tetsuya; Tomitsuka, Tomohiro; Asai, Masato; Ito, Yuta; Shirai, Kaori*; Suzuki, Hayato; Tokoi, Katsuyuki; Toyoshima, Atsushi; Tsukada, Kazuaki; et al.

Journal of Radioanalytical and Nuclear Chemistry, 320(3), p.633 - 642, 2019/06

 Times Cited Count:0 Percentile:100(Chemistry, Analytical)

An isothermal gas-chromatographic (IGC) device has been developed and tested for on-line gas phase studies of volatile oxychlorides of short-lived group-5 transition metals. Radioisotopes of niobium and tantalum, produced in nuclear fusion evaporation reactions, are directly flushed into the IGC setup by an inert gas-jet. Oxychloride compounds are formed by the addition of SOCl$$_2$$ and O$$_2$$. Parameters influencing the formation and transport of NbOCl$$_3$$ and TaOCl$$_3$$ are investigated. For nuclides with half-lives ($$t_{1/2}$$) of about 30 s, an overall efficiency of 7% is obtained, rendering the IGC setup suitable for the chemical exploration of $$^{262}$$Db($$t_{1/2}$$ = 34s).

Journal Articles

Inverse odd-even staggering in nuclear charge radii and possible octupole collectivity in $$^{217,218,219}$$At revealed by in-source laser spectroscopy

Barzakh, A. E.*; Cubiss, J. G.*; Andreyev, A. N.; Seliverstov, M. D.*; Andel, B.*; Antalic, S.*; Ascher, P.*; Atanasov, D.*; Beck, D.*; Biero$'n$, J.*; et al.

Physical Review C, 99(5), p.054317_1 - 054317_9, 2019/05

 Times Cited Count:3 Percentile:22.15(Physics, Nuclear)

Journal Articles

Formation and thermochemical properties of oxychlorides of niobium (Nb) and tantalum (Ta); Towards the gas-phase investigation of dubnium (Db) oxychloride

Chiera, N. M.; Sato, Tetsuya; Tomitsuka, Tomohiro; Asai, Masato; Suzuki, Hayato*; Tokoi, Katsuyuki; Toyoshima, Atsushi; Tsukada, Kazuaki; Nagame, Yuichiro

Inorganica Chimica Acta, 486, p.361 - 366, 2019/02

 Times Cited Count:1 Percentile:69.74(Chemistry, Inorganic & Nuclear)

The formation of NbOCl$$_3$$ and TaOCl$$_3$$ and their adsorption behavior on quartz surfaces was explored by applying an isothermal gas-chromatographic method. Trace amounts of short-lived Nb and Ta isotopes were used. Adsorption enthalpy values ($$Delta H_{rm ads}$$) at zero surface coverage of -$$Delta H_{rm ads}$$(NbOCl$$_3$$) = 102 $$pm$$ 4 kJ/mol and -$$Delta H_{rm ads}$$(TaOCl$$_3$$) = 128 $$pm$$ 5 kJ/mol were determined by analyzing the chromatographic behavior of the Nb andTa complexes with a Monte-Carlo simulation method based on an adsorption-desorption kinetic model.By applying an empirical correlation, the experimental $$Delta H_{rm ads}$$ values were successively related to the macroscopic standard sublimation enthalpy, $$Delta H^circ _{rm subl}$$, as a measure of the volatility of each substance. The inferred sublimation enthalpies are in agreement with tabulated thermochemical values. Thus, the linear empirical correlation between $$Delta H_{rm ads}$$ and $$Delta H^circ _{rm subl}$$ for metal-oxychlorides was updated with the inclusion of the present data. According to the predicted $$Delta H^circ _{rm subl}$$(DbOCl$$_3$$), a $$Delta H_{rm ads}$$(DbOCl$$_3$$) value of 135 $$pm$$ 2 kJ/mol was extrapolated. The future accomplishment of comparative studies with DbOCl$$_3$$ under the same experimental conditions will provide valuable information on the volatility trend in Group-5 elements, together with an indication on the magnitude of relativistic effects on the electronic structure of dubnium.

Journal Articles

Online chemical adsorption studies of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Lens, L.*; Yakushev, A.*; D$"u$llmann, Ch. E.*; Asai, Masato; Ballof, J.*; Block, M.*; David, H. M.*; Despotopulos, J.*; Di Nitto, A.*; Eberhardt, K.*; et al.

Radiochimica Acta, 106(12), p.949 - 962, 2018/12

 Times Cited Count:1 Percentile:73.25(Chemistry, Inorganic & Nuclear)

Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO$$_{2}$$ or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO$$_{2}$$ surface at room temperature. On the other hand, the Hg did not adsorb on the SiO$$_{2}$$ surface, but adsorbed on the Au surface. The results demonstrated that the adsorption properties of short-lived Hg, Tl, and Pb could be studied with this setup, and that this method is applicable to the experiment for Cn, Nh, and Fl.

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:12 Percentile:26.03(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

Liquid-phase chemistry of rutherfordium (Rf), dubnium (Db) and seaborgium (Sg)

Nagame, Yuichiro

Radioisotopes, 67(10), p.507 - 526, 2018/10

Recent studies of the chemical separation and characterization experiments of the first three transactinide elements, rutherfordium (Rf), dubnium (Db) and seaborgium (Sg), conducted atom-at-a-time in liquid phases, are reviewed. A short description on experimental techniques based on partition methods, specifically automated rapid chemical separation systems, as well as on assessment of role of relativistic effects is also given. Perspectives for liquid phase chemistry experiments on heavier elements are briefly discussed.

Journal Articles

Charge radii and electromagnetic moments of $$^{195-211}$$At

Cubiss, J.*; Andreyev, A. N.; Mitsuoka, Shinichi*; Nagame, Yuichiro; Nishio, Katsuhisa; Ota, Shuya*; Wakabayashi, Yasuo*; 60 of others*

Physical Review C, 97(5), p.054327_1 - 054327_19, 2018/05

 Times Cited Count:18 Percentile:4.13(Physics, Nuclear)

Journal Articles

Study of fission using multi-nucleon transfer reactions

Nishio, Katsuhisa; Hirose, Kentaro; Vermeulen, M. J.; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Sato, Tetsuya; Nagame, Yuichiro; et al.

EPJ Web of Conferences, 163, p.00041_1 - 00041_6, 2017/11

 Times Cited Count:1 Percentile:100

Journal Articles

Chemical properties of rutherfordium (Rf) and dubnium (Db) in the aqueous phase

Nagame, Yuichiro; Kratz, J. V.*; Sch$"a$del, M.*

EPJ Web of Conferences, 131, p.07007_1 - 07007_8, 2016/12


 Times Cited Count:3 Percentile:17.71

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

Complex chemistry with complex compounds

Eichler, R.*; Asai, Masato; Brand, H.*; Chiera, N. M.*; Di Nitto, A.*; Dressler, R.*; D$"u$llmann, Ch. E.*; Even, J.*; Fangli, F.*; Goetz, M.*; et al.

EPJ Web of Conferences, 131, p.07005_1 - 07005_7, 2016/12

 Times Cited Count:1 Percentile:47.11

In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the productions and investigations of fragile single molecular species of superheavy elements. The latest highlight is the formation of very volatile hexacarbonyl compound of element 106, Sg(CO)$$_{6}$$. Following this success, second-generation experiments were performed to measure the first bond dissociation energy between the central metal atom and the surrounding ligand. The method using a tubular decomposition reactor was developed and successfully applied to short-lived Mo(CO)$$_{6}$$, W(CO)$$_{6}$$, and Sg(CO)$$_{6}$$.

Journal Articles

$$beta$$-delayed fission and $$alpha$$ decay of $$^{196}$$At

Truesdale, V. L.*; Andreyev, A.; Ghys, L.*; Huyse, M.*; Van Duppen, P.*; Sels, S.*; Andel, B.*; Antalic, S.*; Barzakh, A.*; Capponi, L.*; et al.

Physical Review C, 94(3), p.034308_1 - 034308_11, 2016/09

 Times Cited Count:7 Percentile:36.29(Physics, Nuclear)

Journal Articles

Vacuum chromatography of Tl on SiO$$_{2}$$ at the single-atom level

Steinegger, P.*; Asai, Masato; Dressler, R.*; Eichler, R.*; Kaneya, Yusuke*; Mitsukai, Akina*; Nagame, Yuichiro; Piguet, D.*; Sato, Tetsuya; Sch$"a$del, M.; et al.

Journal of Physical Chemistry C, 120(13), p.7122 - 7132, 2016/04

 Times Cited Count:12 Percentile:48.17(Chemistry, Physical)

A new experimental method "vacuum chromatography" has been developed to measure adsorption enthalpy of superheavy elements, and its feasibility has been examined using short-lived thallium isotopes. The short-lived thallium isotopes were produced at the JAEA tandem accelerator. The thallium ion beam prepared with an on-line isotope separator which ionized and mass-separated the thallium isotopes was injected into an isothermal vacuum chromatography apparatus. A temperature-dependent adsorption property of thallium atom on SiO$$_{2}$$ surface were measured. The adsorption enthalpy of thallium was determined to be 158 kJ/mol. The thallium is a homolog of element 113. Thus, the vacuum chromatography developed in this study enables us to perform chemical experiments for short-lived superheavy elements with half-lives of a order of one second.

JAEA Reports

Reports on JAEA's Reimei Research Program; April 1, 2013 - March 31, 2015

Nagame, Yuichiro

JAEA-Review 2015-039, 50 Pages, 2016/03


Advanced Science Research Center set out "Reimei (Dawn) Research Program" with the aim to cultivate forefront and frontier researches. This report compiles the summaries of the research subjects carried out in the fiscal year of 2013 and 2014.

Journal Articles

Lawrencium's place at the table

Nagame, Yuichiro

Nature Chemistry, 8(3), P. 282, 2016/03

We summarize the studies of element 103, lawrencium: discovery or synthesis in nuclear reactions, historical argument for recognition as a new element, nuclear and chemical studies of lawrencium isotopes, and recently measured ionization energy. Based on the studies so far performed, we introduce a debate that has emerged over the place in the periodic table.

Journal Articles

Lawrencium's ionization potential, atom by atom (original title)

Nagame, Yuichiro

Pariti, 31(3), p.40 - 41, 2016/03

no abstracts in English

422 (Records 1-20 displayed on this page)