[en] The alpha decay half lives for the isotopes of Cm nuclei in the range 238≤A≤250 and Cf nuclei in the range 240≤A≤256 have been studied using CYEM model by including deformation effects. The computed half-lives are compared with available data and are found in good agreement. The calculated hindrance factor is found to be closer to unity. (author)

[en] Alpha decays of ²³⁷Cm and ²³⁸Cm have been studied using a gas-jet coupled on-line isotope separator. The new isotope ²³⁷Cm has been identified through the detection of 6656±10 keV α particles. The α energy of ²³⁸Cm has been revised more precisely than the previous one. The α transition to the first excited 2⁺ state in ²³⁴Pu has also been observed. It was found that the 2⁺ energy in ²³⁴Pu is much higher than those in heavier Pu isotopes

[en] The ratios of cumulative yields of the ¹³⁵I isotope and the independent yield of ¹³⁵Xe at photofission of ²³²Th, ²³⁸U, ²³⁷Np, ²⁴³Am, and ²³⁸Cm by bremsstrahlung radiation with a boundary energy of 25 MeV are measured. The selective gas transportation of fission fragments and a measurement of the spectra of their γ radiation were used. A large difference in the ratios of the yields for these targets was discovered: from 34 for ²³⁸U to 1.3 for ²⁴³Am. This difference is discussed based on the known ideas of the formation mechanism of fission fragments.

No abstract available

[en] A search for the α-decay of ²³⁹Cm was carried out via the fusion reaction ²³²Th(¹²C, 5n)²³⁹Cm at GSI, applying nuclear chemistry techniques. The ²³⁹Cm α-decay would provide a link between known nuclear masses and α-decay energies measured in the region of the superheavy elements. Three different ¹²C beam energies were chosen in the present experiments. The α peaks of ^238,240Cm were observed clearly at a ¹²C energy of 74 MeV, while ²³⁸Cm disappeared at 70 MeV to provide an undisturbed α-spectrum for a sensitive search of ²³⁹Cm decay. No α-events between 6.34 and 6.50 MeV, which could be assigned to ²³⁹Cm with confidence, were observed in this experiment. The upper limit of the α-branch of ²³⁹Cm was less than 1.0 x 10^-5. (orig.)

[en] The available nuclear structure information for all nuclei with mass number A=238 is presented. Various decay and reaction data are evaluated and compared. Adopted data, levels, spin, parity and configuration assignments are given

[en] Heavy element nuclear chemistry research in JAERI is reviewed. Recent experimental results on decay studies of neutron deficient actinide nuclei using the gas-jet coupled JAERI-ISOL are presented. Successful production of the transactinide nuclei, ²⁶¹Rf and ²⁶²Db, and the present status of studies of chemical properties on the transactinide elements are introduced. (author)

[en] Measurements of EC and weak α decays of neutron-deficient americium and curium isotopes have been performed using a gas-jet coupled on-line isotope separator. Decay schemes of ^{235, 236}Am have been established for the first time, and proton-neutron configurations in ^{235, 236}Am and their EC-decay daughters ^{235, 236}Pu have been evaluated. Qa values were derived from measured α-particle energies for ^{235, 236}Am and ²³⁸Cm as well as for the new isotopes ²³³Am and ²³⁷Cm. (author)

[en] Nuclear decay properties of the neutron-deficient actinide isotopes ^{233,234,235,236}Am and ^237,238Cm have been investigated using a gas-jet coupled on-line isotope separator at the JAERI tandem accelerator facility. Alpha-decays of ^233,235,236Am and ^237,238Cm produced in the ⁶Li-induced reactions on ^233,235U and ²³⁷Np targets have been observed with unambiguous mass identification, and the new isotopes ²³³Am and ²³⁷Cm have been identified for the first time. Alpha-particle energies, Q_α values, half-lives and α-branching intensities were determined and the observed α decays of ²³³Am and ²³⁵Am are regarded as the favored transition. (author)

[en] The EC and α decays of neutron-deficient Am and Cm nuclei have been studied using a gas-jet coupled on-line isotope separator. Decay schemes of the EC decay of ^235,236Am have been constructed, and weak α decays of ^233,235,236Am and ^237,238Cm have been observed. The efficiency of the on-line mass separation of Bk nuclei was measured to be ∼1%. The Q_α values, α-decay partial half-lives, and proton-neutron configurations are discussed. (author)