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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

https://doi.org/10.1051/epjconf/201613105001
 Times Cited Count：0 Percentile：0.9(Chemistry, Inorganic & Nuclear)

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

https://doi.org/10.1038/nature14342
 Times Cited Count：107 Percentile：97.49(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

https://doi.org/10.1007/s10967-014-3467-5
 Times Cited Count：8 Percentile：56.13(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

Production of $$^{256}$$Lr in the $$^{249,250,251}$$Cf + $$^{11}$$B, $$^{243}$$Am + $$^{18}$$O, and $$^{248}$$Cm + $$^{14}$$N reactions

Sato, Nozomi; Sato, Tetsuya; Asai, Masato; Toyoshima, Atsushi; Tsukada, Kazuaki; Li, Z.*; Nishio, Katsuhisa; Nagame, Yuichiro; Sch$"a$del, M.; Haba, Hiromitsu*; et al.

Radiochimica Acta, 102(3), p.211 - 219, 2014/03

https://doi.org/10.1515/ract-2014-2142
 Times Cited Count：9 Percentile：57.19(Chemistry, Inorganic & Nuclear)

Production cross-sections of the isotope $$^{256}$$Lr in the $$^{249,250,251}$$Cf + $$^{11}$$B, $$^{243}$$Am + $$^{18}$$O, and $$^{248}$$Cm + $$^{14}$$N reactions were measured using a He/KCl gas-jet transport system and a rotating wheel $$alpha$$-particle detection apparatus. The $$alpha$$-particle energy of $$^{256}$$Lr was distributed from 8.3 to 8.7 MeV and its half-life, $$T_{1/2}$$, was measured to be $$28 pm 1$$ s. The maximum cross sections in the $$^{249}$$Cf($$^{11}$$B, 4$$n$$)$$^{256}$$Lr and $$^{243}$$Am($$^{18}$$O, 5$$n$$)$$^{256}$$Lr reactions were determined to be $$122 pm 6$$ nb at the beam energy of 63 MeV and $$26 pm 3$$ nb at 96 MeV, respectively. In the $$^{248}$$Cm($$^{14}$$N, 6$$n$$)$$^{256}$$Lr reaction, the cross section was measured to be $$27 pm 1$$ nb at 91 MeV.

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

https://doi.org/10.1063/1.4789772
 Times Cited Count：16 Percentile：58.95(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.

Journal Articles

Production of $$^{256}$$Lr in the $$^{248}$$Cm + $$^{14}$$N reaction

Sato, Nozomi; Sato, Tetsuya; Asai, Masato; Toyoshima, Atsushi; Tsukada, Kazuaki; Li, Z.*; Nishio, Katsuhisa; Nagame, Yuichiro; Sch$"a$del, M.; Haba, Hiromitsu*; et al.

RIKEN Accelerator Progress Report, Vol.46, P. 237, 2013/00

http://www.rarf.riken.jp/researcher/APR/Document/ProgressReport_vol_46.pdf

Due to the strong relativistic effects, the weakly-bound outermost electron results in a significantly low first ionization potential (IP) of Lr as compared with its neighboring heavy actinides. The isotope $$^{256}$$Lr, with a relatively long half-life of 27 s, is the suitable candidates for the IP measurement of Lr through the surface ionization method. In the present study, we measured the cross section of the $$^{248}$$Cm($$^{14}$$N, 6$$n$$)$$^{256}$$Lr reaction to evaluate the production rate of $$^{256}$$Lr. A $$^{248}$$Cm target with 960 $$pm$$ 60 $$mu$$g/cm$$^{2}$$ thickness was bombarded with a $$^{14}$$N$$^{5+}$$ beam from the RIKEN AVF Cyclotron. The beam energy was 91 MeV in the middle of the target. The average beam intensity was 1.2 particle-$$mu$$A. Reaction products were transported to the rotating wheel $$alpha$$-particle detection system with a He/KCl gas-jet system. The $$^{256}$$Lr cross section of 27$$pm$$1 nb was calculated based on the $$alpha$$-particle events between 8.3 and 8.7 MeV.

Journal Articles

Production and decay properties of $$^{264}$$Hs and $$^{265}$$Hs

Sato, Nozomi; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Kaji, Daiya*; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozeki, Kazutaka*; Sumita, Takayuki*; Yoneda, Akira*; et al.

Journal of the Physical Society of Japan, 80(9), p.094201_1 - 094201_7, 2011/09

https://doi.org/10.1143/JPSJ.80.094201
 Times Cited Count：15 Percentile：65.33(Physics, Multidisciplinary)

Decay properties of $$^{264}$$Hs and $$^{265}$$Hs produced in the $$^{207,208}$$Pb($$^{58}$$Fe, $$xn$$) [$$x$$=1, 2] reactions were studied using a gas-filled recoil ion separator at the linear accelerator facility of RIKEN. A total of 6 decay chains were assigned to $$^{264}$$Hs. Cross sections for the $$^{264}$$Hs production in the $$^{208}$$Pb($$^{58}$$Fe,$$2n$$) and $$^{207}$$Pb($$^{58}$$Fe,$$n$$) reactions were measured to be $$2.8^{+6.5}_{-2.3}$$pb and $$6.9^{+4.4}_{-3.1}$$pb, respectively. The isotope $$^{264}$$Hs decayed with a half-life of $$0.751^{+0.518}_{-0.218}$$ms by $$alpha$$-particle emission and spontaneous fission. The $$alpha$$-particle energy of $$^{264}$$Hs was observed at 10.61$$pm$$0.04 and 10.80$$pm$$0.08 MeV. The spontaneous fission branch of $$^{264}$$Hs was found to be $$17^{+38}_{-14}%$$.

Journal Articles

Decay properties of $$^{266}$$Bh and $$^{262}$$Db produced in the $$^{248}$$Cm + $$^{23}$$Na reaction

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi*; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.

Journal of the Physical Society of Japan, 78(6), p.064201_1 - 064201_6, 2009/06

https://doi.org/10.1143/JPSJ.78.064201
 Times Cited Count：30 Percentile：78.34(Physics, Multidisciplinary)

Decay properties of an isotope $$^{266}$$Bh and its daughter nucleus $$^{262}$$Db produced by the $$^{248}$$Cm($$^{23}$$Na,5$$n$$) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. $$^{266}$$Bh was clearly identified from the correlation of the known nuclide, $$^{262}$$Db. The obtained decay properties of $$^{266}$$Bh and $$^{262}$$Db are consistent with those observed in the $$^{278}$$113 chain, which provided further confirmation of the discovery of $$^{278}$$113.

Journal Articles

Production of a new hassium isotope $$^{263}$$Hs

Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Ozeki, Kazutaka*; Haba, Hiromitsu*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; et al.

Journal of the Physical Society of Japan, 78(3), p.035003_1 - 035003_2, 2009/03

https://doi.org/10.1143/JPSJ.78.035003

A new hassium isotopes $$^{263}$$Hs is directly produced for the first time. The experiment was performed at the linear accelerator (RILAC) facility in RIKEN (the Institute of Physical and Chemical Research) from Jun. 19 to 25. In the 25-h irradiation of $$^{58}$$Fe on $$^{206}$$Pb and 46-h irradiation of $$^{56}$$Fe on $$^{208}$$Pb, 8 decay chains and 1 decay chain, respectively, were observed. All decay chains were assigned to subsequent decays from $$^{263}$$Hs. The half-life of $$^{263}$$Hs is 0.60$$^{+0.30}_{-0.15}$$ ms. In this experiment, the total beam dose was $$4.1times10^{17}$$ ions for $$^{58}$$Fe and $$6.2times10^{17}$$ ions for $$^{56}$$Fe. The production cross section corresponding to 8 decay events and 1 decay chain was deduced to be 21$$^{+10}_{-8}$$ pb and 1.6$$^{+3.7}_{-1.3}$$ pb by assuming that the transmission of the system is 80%.

Journal Articles

Production and decay properties of $$^{263}$$Hs

Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Ozeki, Kazutaka*; Haba, Hiromitsu*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; et al.

Journal of the Physical Society of Japan, 78(3), p.035003_1 - 035003_2, 2009/03

https://doi.org/10.1143/JPSJ.78.035003
 Times Cited Count：3 Percentile：26.3(Physics, Multidisciplinary)

A new neutron deficient hassium ($$Z$$=108) isotope of $$^{263}$$Hs was identified via two different reactions of $$^{206}$$Pb($$^{58}$$Fe,n) and $$^{208}$$Pb($$^{56}$$Fe,n) by using a gas-filled recoil separator GARIS at June 2008. During the 25-h irradiation of $$^{206}$$Pb with the $$^{58}$$Fe beam and 46-h irradiation of $$^{208}$$Pb with the $$^{56}$$Fe beam, 8 decay chains and 1 decay chain, respectively, have been observed. The half-life of $$^{263}$$Hs is 0.60$$^{+0.30}_{0.15}$$ ms. In this experiment, the total beam doses of the Fe and $$^{56}$$Fe was 4.1$$times$$10$$^{17}$$ ions and 6.2$$times$$10$$^{17}$$ ions, respectively. The production cross sections corresponding to the 8 decay chains and 1 decay chain have been deduced to be 21$$^{+10}_{-8}$$ pb and 1.6$$^{+3.7}_{-1.3}$$ pb by assuming the transmission of the system to be 80%.

Journal Articles

New decay properties of $$^{264}$$Hs, $$^{260}$$Sg, and $$^{256}$$Rf

Sato, Nozomi*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Kaji, Daiya*; Koura, Hiroyuki; Kudo, Yuki*; Morimoto, Koji*; Morita, Kosuke*; Ozawa, Akira*; et al.

RIKEN Accelerator Progress Report, Vol.42, P. 16, 2009/00

http://www.rarf.riken.jp/researcher/APR/Document/2008.pdf

New Decay Properties of $$^{264}$$Hs and its $$alpha$$-decay daughter nuclei were studied by using reactions of $$^{208}$$Pb($$^{58}$$Fe,2n) and $$^{207}$$Pb($$^{58}$$Fe,n) by using a gas-filled recoil ion separator, GARIS at RIKEN. We observed three correlated events in irradiation of $$^{58}$$Fe on $$^{208}$$Pb, and eight events in irradiation of $$^{58}$$Fe on $$^{207}$$Pb. A half-life was deduced to be 0.90$$^{+0.40}_{-0.20}$$. We assigned these eleven events to be the decays of $$^{264}$$Hs. We found different decay-chain events of $$^{264}$$Hs from a previous report. One is a long-lived $$alpha$$-decay of $$^{260}$$Sg with 180$$^{150}_{-60}$$ms of half-life. Another is a long-lived $$alpha$$-decay of $$^{256}$$Rf with 10.4$$^{8.4}_{-3.2}$$s of half-life. For $$^{260}$$Sg and $$^{256}$$Rf, the decay of such a long-lived state have not been reported. These are the first observations of isomerism in $$^{260}$$Sg and $$^{256}$$Rf.

Oral presentation

Productions and decay properties of $$^{264,265}$$Hs

Sato, Nozomi; Kaji, Daiya*; Morimoto, Koji*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.

no journal, , 

In this work, the production and decay properties of $$^{264,265}$$Hs produced in the $$^{208}$$Pb($$^{58}$$Fe, $$xn$$) [$$x = 1,2$$] and $$^{207}$$Pb($$^{58}$$Fe, $$n$$) reactions were investigated. The experiment was performed at the RILAC facility in RIKEN. The evaporation residues (ERs) were separated from the primary beam with the gas-filled recoil ion separator, GARIS. In the focal plane of GARIS the products were implanted into a position-sensitive Si detector for measuring the arrival of ERs and subsequent $$alpha$$-decays or spontaneous fission from ERs. We have measured production cross-sections of $$^{264,265}$$Hs in the $$^{58}$$Fe + $$^{208}$$Pb reaction at several bombarding energies. For the $$^{208}$$Pb($$^{58}$$Fe, $$n$$)$$^{265}$$Hs reaction, the cross-section maximum of ($$51^{+46}_{-29}$$) pb was obtained at the bombarding energy of 220.5 MeV at the middle of the target. For even-even nucleus $$^{264}$$Hs, we have also observed accurate decay data with good statistics.

Oral presentation

Productions and decay properties of a new isotope of $$^{263}$$Hs

Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.

no journal, , 

A new neutron deficient hassium ($$Z=108$$) isotope of $$^{263}$$Hs was identified via two different reactions of $$^{206}$$Pb($$^{58}$$Fe,$$n$$) and $$^{208}$$Pb($$^{56}$$Fe,$$n$$) by using the gas-filled recoil separator GARIS. During irradiation of $$^{206}$$Pb with the $$^{58}$$Fe beam and irradiation of $$^{208}$$Pb with the $$^{56}$$Fe beam, 8 decay chains and 1 decay chain, respectively, were observed. The properties of decay events obtained by irradiation of $$^{58}$$Fe on $$^{206}$$Pb match well with those by irradiation of $$^{56}$$Fe on $$^{208}$$Pb. The mean $$alpha$$-decay energies for the 3 groups are 10.82, 10.55, and 10.37 MeV, respectively. The half-life of $$^{263}$$Hs is determined to be 0.60 ms.

Oral presentation

Production and decay properties of $$^{266}$$Bh and its daughter nuclei

Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.

no journal, , 

A nuclide, $$^{266}$$Bh, is the great-grand-daughter of $$^{278}$$113 that is produced in the $$^{209}$$Bi + $$^{70}$$Zn reaction. The identification was based on a genetic link to the known daughter nucleus $$^{262}$$Db by alpha-decays. The main purpose of this work is to provide further confirmation of the production and identification of the isotope $$^{278}$$113. As a present result, a state in $$^{266}$$Bh, which decays by an alpha emission with the energies ranging from 9.05 to 9.23 MeV, feeds a state in $$^{262}$$Db, which decays by alpha emission and by SF with a previously known half-life. The result provided a further confirmation of the production and identification of the isotope of the 113th element, $$^{278}$$113, studied by a research group at RIKEN.

Oral presentation

Production and decay properties of $$^{266}$$Bh and its daughter nuclei

Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Productions and decay properties of a new isotope of $$^{263}$$Hs

Kaji, Daiya*; Morimoto, Koji*; Sato, Nozomi; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.

no journal, , 

no abstracts in English

Oral presentation

Production and decay properties of $$^{263,264,265}$$Hs

Sato, Nozomi; Kaji, Daiya*; Morimoto, Koji*; Haba, Hiromitsu*; Ichikawa, Takatoshi*; Ideguchi, Eiji*; Koura, Hiroyuki; Kudo, Yuki*; Ozawa, Akira*; Ozeki, Kazutaka*; et al.

no journal, , 

In the superheavy nuclei region, the deformed proton shell at $$Z=108$$ and neutron shells at $$N=152$$ and 162 have been found. $$^{260}$$Hs with $$Z=108$$ and $$N=152$$ is expected to be the doubly deformed magic nuclei, however, decay properties of $$^{260}$$Hs and its neighboring nuclei is not well known. In order to approach $$^{260}$$Hs, we synthesized $$^{263,264,265}$$Hs by $$^{208}$$Pb($$^{58}$$Fe,xn) [$$x=1, 2$$], $$^{207}$$Pb($$^{58}$$Fe,n), $$^{206}$$Pb($$^{58}$$Fe,n), $$^{208}$$Pb($$^{56}$$Fe,n) reactions. The experiment was performed with the gas-filled recoil ion separator GARIS at the linear accelerator facility in RIKEN. In this work, 9 $$alpha$$-decay events of $$^{263}$$Hs were observed with half-life $$T_{1/2}=0.60^{+0.30}_{-0.15}$$ ms and $$alpha$$-decay energy $$Q_{alpha}=10.99$$ MeV. For $$^{264}$$Hs, we have also observed new $$alpha$$-particle energy, 10.65 MeV. $$Q_{alpha}$$ values of $$^{263,264,265}$$Hs isotopes increase with decreasing neutron number.

Oral presentation

Measurement of the first ionization potential of Lr

Sato, Nozomi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi; Li, Z.; Nagame, Yuichiro; Sch$"a$del, M.; Ichikawa, Shinichi

no journal, , 

First ionization potentials (IPs) of heavy elements with atomic numbers Z $$>$$ 100 have not been determined up to now. Recently we have been developing a surface ionization type ion source to measure the IP of the heaviest actinide, lawrencium (Lr, Z = 103). The surface ionization comparison technique is a promising approach to measure the IP of Lr on an atom-at-a-time scale. We will present the status of our development for an apparatus for this measurement.

Oral presentation

Development of a surface ionizer coupled to a gas-jet transport system for the measurement of the first ionization potential of Lr

Sato, Nozomi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi; Li, Z.; Kikuchi, Takahiro; Kaneya, Yusuke*; Ichikawa, Shinichi; Nagame, Yuichiro; et al.

no journal, , 

It is important to determine the first ionization potentials (IPs) of the heaviest elements with atomic number Z $$>$$ 100 to understand their valence electronic structure affected by relativistic effects. Due to low production rates and short half-lives of the heaviest nuclides, IPs of these elements have not been so far determined. We are developing a surface-ionization-type ion source coupled to a gas-jet transport system in the Isotope Separator On-Line (ISOL) at the JAEA tandem accelerator facility to measure the IP of the heaviest actinide, lawrencium (Lr, Z = 103). In the symposium, we report the present status of the development of the apparatus. Production yield measurements of $$^{256}$$Lr (half-life 27 s), that is suitable for this study, will be also presented.

Oral presentation

Confirmations of the synthesis of $$^{278}$$113 produced by the $$^{209}$$Bi($$^{70}$$Zn,n)$$^{278}$$113 reaction

Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sato, Nozomi; Sumita, Takayuki*; Yoneda, Akira*; Ichikawa, Takatoshi*; et al.

no journal, , 

We performed the experiment to synthesize an isotope of the element 113 produced by a $$^{209}$$Bi($$^{70}$$Zn,n)$$^{278}$$113 reaction using a gas-filled recoil ion separator (GARIS) at RIKEN. Two decay chains were observed, and assigned to those originating from an isotope $$^{278}$$113. Both chains were connected into the previously known decays of $$^{266}$$Bh and $$^{262}$$Db via previously unknown decays of $$^{278}$$113, $$^{274}$$Rg, and $$^{270}$$Mt. Although the $$^{266}$$Bh was known nuclide, a number of atoms reported so far was limited. In order to study more precise decay property of the $$^{266}$$Bh, we performed the direct production of $$^{266}$$Bh by the $$^{248}$$Cm($$^{23}$$Na,5n)$$^{266}$$Bh reaction. In this experiment, the $$^{266}$$Bh was clearly identified from the correlation of the nuclide, $$^{262}$$Db. The obtained decay properties of $$^{266}$$Bh and $$^{262}$$Db are consistent with those observed in the $$^{278}$$113 chain, which provided further confirmation of the discovery of $$^{278}$$113.

39 (Records 1-20 displayed on this page)