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Eichler, R.*; 浅井 雅人; Brand, H.*; Chiera, N. M.*; Di Nitto, A.*; Dressler, R.*; Dllmann, Ch. E.*; Even, J.*; Fangli, F.*; Goetz, M.*; et al.
EPJ Web of Conferences, 131, p.07005_1 - 07005_7, 2016/12
被引用回数:2 パーセンタイル:73.04近年、物理的な前段分離装置を活用することにより、超重元素の比較的不安定な単一分子の合成と研究が気相化学研究によって可能になった。非常に揮発性の高い106番元素のヘキサカルボニル錯体Sg(CO)の合成は最近の大きな成果である。この成功を受けて、中心金属原子と周囲の配位子間の第一乖離エネルギーの測定を第2世代の実験として実施した。管状の分解反応装置を用いた手法を開発し、短寿命のMo(CO), W(CO), Sg(CO)錯体に適用することに成功した。
Ross, T. J.*; Hughes, R. O.*; Allmond, J. M.*; Beausang, C. W.*; Angell, C.; Basunia, M. S.*; Bleuel, D. L.*; Hurke, J. T.*; Casperson, R. J.*; Escher, J. E.*; et al.
Physical Review C, 90(4), p.044323_1 - 044323_12, 2014/10
被引用回数:7 パーセンタイル:47.25(Physics, Nuclear)Low-spin single quasi neutron levels in Gd and Gd have been studied following the Gd () Gd and Gd () Gd reactions. A combined Si telescope and high-purity germanium array was utilized, allowing - and -- coincidence measurements. Almost all of the established low-excitation-energy, low-spin structures were confirmed in both Gd and Gd. Several new levels and numerous new rays are observed in both nuclei, particularly for 1 MeV. Residual effects of a neutron sub shell closure at = 64 are observed in the form of a large excitation energy gap in the single quasi neutron level schemes.
Ross, T. J.*; Hughes, R. O.*; Beausang, C. W.*; Allmond, J. M.*; Angell, C.; Basunia, M. S.*; Bleuel, D. L.*; Burke, J. T.*; Casperson, R. J.*; Escher, J. E.*; et al.
Physical Review C, 88(3), p.031301_1 - 031301_4, 2013/09
被引用回数:7 パーセンタイル:48.17(Physics, Nuclear)Odd-mass gadolinium isotopes around = 90 were populated by the () reaction, utilizing 25-MeV protons, resulting in population of low-spin quasi-neutron states at energies near and below the Fermi surface. Systematics of the single quasi-neutron levels populated are presented. A large excitation energy gap is observed between levels originating from the , and spherical parents (above the = 64 gap), and the (below the gap) indicating that the spherical shell model level spacing is maintained at least to moderate deformations.
Iyengar, A.*; Norman, E. B.*; Howard, C.*; Angell, C.; Kaplan, A.*; Ressler, J. J.*; Chodash, P.*; Swanberg, E.*; Czeszumska, A.*; Wang, B.*; et al.
Nuclear Instruments and Methods in Physics Research B, 304, p.11 - 15, 2013/06
被引用回数:8 パーセンタイル:53.67(Instruments & Instrumentation)Measurements of beta-delayed -ray spectra following 14-MeV neutron-induced fissions of Th, U, and Np were conducted at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. Spectra were collected for times ranging from 1 minute to 14 hours after irradiation. Intensity ratios of -ray lines were extracted from the data that allow identification of the fissioning isotope.
Czeszumska, A.*; Angell, C.; Burke, J. T.*; Scielzo, N. D.*; Norman, E. B.*; Austin, R. A. E.*; Boutoux, G.*; Casperson, R. J.*; Chodash, P.*; Hughes, R. O.*; et al.
Physical Review C, 87(3), p.034613_1 - 034613_6, 2013/03
被引用回数:12 パーセンタイル:64.7(Physics, Nuclear)Neutron-induced fission cross section data are needed in various fields of applied and basic nuclear science. However, cross sections of short-lived nuclei are difficult to measure directly due to experimental constraints. The first experimental determination of the neutron-induced fission cross section of Np at non-thermal energies was performed. The Surrogate Ratio Method (SRM) was employed to indirectly deduce the Np(,) cross section. The surrogate reactions used were U and U with the reference cross section given by the well-known Np(,) cross section. The ratio of observed fission reactions resulting from the two formed compound nuclei, Np and Np, was multiplied by the directly-measured Np(,) cross section to determine theNp(,) cross section. The Np(,) cross section was determined with an uncertainty ranging between 3 - 30% over the energy range of 0.2 - 20 MeV.
Andreyev, A. N.*; Antalic, S.*; Ackermann, D.*; Bianco, L.*; Franchoo, S.*; Heinz, S.*; Heberger, F. P.*; Hofmann, S.*; Huyse, M.*; Kalaninov, Z.*; et al.
Physical Review C, 87(1), p.014317_1 - 014317_8, 2013/01
被引用回数:24 パーセンタイル:80.42(Physics, Nuclear)By using the recoil-fission correlation technique, the exotic process of beta-delayed fission (DF) was unambiguously identified in the very neutron-deficient nuclei At in experiments at the velocity filter SHIP at Gesellschaft fr Schwerionenforschung (GSI). The upper limits for the total kinetic energy release in fission of Po, being the daughter of At after decay, were estimated. The possibility of an unusually high DF probability At is discussed.
Ross, T. J.*; Beausang, C. W.*; Hughes, R. O.*; Scielzo, N. D.*; Burke, J. T.*; Allmond, J. M.*; Angell, C.; Basunia, M. S.*; Bleuel, D. L.*; Casperson, R. J.*; et al.
Physical Review C, 86(6), p.067301_1 - 067301_5, 2012/12
被引用回数:3 パーセンタイル:22.8(Physics, Nuclear)Low-spin, high-excitation energy states in Y have been studied using the Y() reaction. For this experiment a 25 MeV proton beam was incident upon a mono-isotopic Y target. A silicon telescope array was used to detect deuterons and coincident rays were detected using a germanium clover array. Most of the known low-excitation energy low-spin states populated strongly via the () reaction mechanism are confirmed. Two states are seen for the first time and seven new transitions, including one which by-passes the two low-lying isomeric states, are observed.
Ross, T. J.*; Beausang, C. W.*; Hughes, R. O.*; Allmond, J. M.*; Angell, C.; Basunia, M. S.*; Bleuel, D. L.*; Burke, J. T.*; Casperson, R. J.*; Escher, J. E.*; et al.
Physical Review C, 85(5), p.051304_1 - 051304_5, 2012/05
被引用回数:11 パーセンタイル:53.91(Physics, Nuclear)代理反応法は、20%の精度でアクチニド核の中性子捕獲断面積を評価することができるが、希土類核に対しては、直接測定した中性子捕獲断面積と23倍の不一致がある。これは、スピン/パリティの生成分布の違いによるものであると考えられる。このことを確かめるために、代理反応におけるガドリニウム核の角運動量移行の測定を行った。
Hofmann, S.*; Ackermann, D.*; Antalic, S.*; Burkhard, H. G.*; Comas, V. F.*; Dressler, R.*; Gan, Z.*; Heinz, S.*; Heredia, J. A.*; Heberger, F. P.*; et al.
European Physical Journal A, 32(3), p.251 - 260, 2007/06
被引用回数:253 パーセンタイル:99.7(Physics, Nuclear)The fusion reaction of Ca projectiles withU target nuclei was studied at the velocity filter SHIP of GSI. Two decay chains were measured, which fully confirm data that were previously assigned to the isotope 112 in experiments at the Flerov Laboratory in Dubna. Two other events are consistent with a 50% spontaneous fission (SF) branch of this isotope. The mean value obtained for the half-life of 112 is (6.9) s, the energy is (9.5200.015) MeV, and the total kinetic energy (TKE) of SF is (23814) MeV. The half-life of the decay daughter nucleus Ds is (0.18) s, and the TKE of SF is (210) MeV. The cross-section deduced from all four events is (0.72) pb, measured at an excitation energy of 34.6 MeV of the compound nucleus 112.
Dvorak, J.*; Brchle, W.*; Chelnokov, M.*; Dressler, R.*; Dllmann, Ch. E.*; Eberhardt, K.*; Gorshkov, V.*; Jger, E.*; Krcken, R.*; Kuznetsov, A.*; et al.
Physical Review Letters, 97(24), p.242501_1 - 242501_4, 2006/12
被引用回数:151 パーセンタイル:96.05(Physics, Multidisciplinary)超重核領域で理論的に予想されていた変形した二重魔法核Hsを初めて実験的に確認した。実験はドイツ重イオン研究所(GSI)で行った。Cm+Mg反応で合成されたHs同位体を、迅速気相化学分離法で選択に分離し、壊変エネルギーとそれに伴う15事象の壊変連鎖からHsを同定した。また壊変エネルギーから値をと決定した。Hsの生成断面積は約3pbであった。
Andreyev, A. N.*; Antalic, S.*; Ackermann, D.*; Franchoo, S.*; Heberger, F. P.*; Hofmann, S.*; Huyse, M.*; Kojouharov, I.*; Kindler, B.*; Kuusiniemi, P.*; et al.
Physical Review C, 73(4), p.044324_1 - 044324_8, 2006/04
被引用回数:36 パーセンタイル:87.06(Physics, Nuclear)The new neutron-deficient isotope Po has been identified in the complete fusion reaction Ti+Sm Po+3n at the velocity filter SHIP of GSI. Striking features of the Po decay are the strongly-hindered decay to the spherical ground state and unhindered decay to a surprisingly low-lying deformed excited state at 286 keV in the daughter nucleus Pb. Based on the potential energy surface calculations, the Po ground state and the 286 keV excited state in Pb were interpreted as being of prolate origin.
Andreyev, A. N.*; Antalic, S.*; Ackermann, D.*; Franchoo, S.*; Heberger, F. P.*; Hofmann, S.*; Huyse, M.*; Kojouharov, I.*; Kindler, B.*; Kuusiniemi, P.*; et al.
Physical Review C, 73(2), p.024317_1 - 024317_11, 2006/02
被引用回数:26 パーセンタイル:81.37(Physics, Nuclear)Decay properties of the new neutron-deficient nuclide At have been studied in the complete fusion reaction Sm(V,3n)At at the velocity filter SHIP of GSI. Two isomeric states with half-lives of 88(6) ms and 11.5(6) ms, respectively, and with complex -decay schemes were identified in At. The decay pattern of one of the isomers suggests that it is based on the oblate-deformed 2f7/2 1i13/2 configuration, which confirms the expected onset of deformation in the At isotopes by approaching the neutron midshell at N=104.