No abstract available

[en] A gas-filled recoil separator for studies of heavy elements produced in heavy-ion-induced fission reaction has been constructed. New neutron-deficient isotopes with Z=85-90 have been identified through their alpha decay. (author). 40 refs, 3 figs, 2 tabs

[en] Detailed level schemes, decay schemes, and the reaction and decay data on which they are base are presented for the nuclei with A + 207. Data received by August 1977 are included

[en] Evaluated nuclear structure and decay data for all nuclei within the A=207 mass chain are presented. The experimental data are evaluated and best values for level and gamma-ray energies, quantum numbers, lifetimes, gamma-ray intensities, and other nuclear properties are recommended. Inconsistencies and discrepancies that exist in the literature are noted. This work supersedes the earlier evaluation by M.J. Martin (1993Ma73), published in Nuclear Data Sheets70, 315 (1993).

[en] Two new neutron-deficient isotopes ^207,208Ac have been produced in fusion reactions with 5.2-5.6 MeV/nucleon ⁴⁰Ar ions on ¹⁷⁵Lu and identified on the basis of genetic correlations. The fusion evaporation products were separated on-line using a gas-filled magnetic recoil separator. The alpha energy and half-life of ²⁰⁸Ac were determined to be (7572±15) keV and (95_-16⁺²⁴) ms, respectively. A nw alpha line with a half-life of (25_-5⁺⁹) ms and an energy of (7758±20) keV is assigned to the decay of an isomeric state in ²⁰⁸Ac. Another new activity with a half-life of (22_-9⁺⁴⁰) ms and an alpha energy of (7712±25) keV is assigned to ²⁰⁷Ac. (orig.)

[en] Neutron-deficient isotopes of radium have been produced in the reactions ³⁵Cl+¹⁷⁵Lu, ⁴⁰Ar+^170,171Yb, and ³⁶Ar+^170,171Yb and separated in-flight with a gas-filled recoil separator. The activities have been identified on the basis of correlated alpha decay chains. The alpha particle energy E_α and the half-life T_1/2 of an isomeric state of the new isotope, ^203mRa, have been determined to be (7615±20) keV and (33⁺²²_-10) ms, respectively. An assignment of another decay with E_α=(7577±20) keV and T_1/2=(1.1^+5.0_-0.5) ms to ^203gRa is made on the basis of one observed three-decay chain. Tentative evidence for the production of the new isotope ²⁰²Ra is also given. The values E_α=(7860±60) keV and T_1/2=(0.7^+3.3_-0.3) ms were measured. Improved decay data have been obtained for ²⁰⁴Ra. The results are E_α=(7484±10) keV and T_1/2=(59⁺¹²_-9) ms. Earlier findings concerning the decay of two states in ²⁰⁵Ra and an isomer in ²⁰⁷Ra have been confirmed. Approximate values for cross sections have been determined for ²⁰²Ra, produced using the ³⁶Ar+¹⁷⁰Yb reaction and for ²⁰³Ra, ²⁰⁴Ra, and ²⁰⁵Ra using the ³⁵Cl+¹⁷⁵Lu reaction. The results are 2 nb (²⁰²Ra), 4 nb (²⁰³Ra), 40 nb (²⁰⁴Ra), and 800 nb (²⁰⁵Ra). (orig.)

[en] The velocity distributions of evaporation residues produced in complete fusion reactions of ²⁰Ne+¹⁹⁷Au at bombarding energies of E/A=5.7, 8.6 and 11.4 MeV/u were measured with use of the velocity filter SHIP. It could be shown, that the production cross section for evaporation residues is influenced by emission of fast, light particles having an angular distribution, that is peaked in forward direction (preequilibrium particles). This contribution is, however too small to explain the enhancement of the evaporation residue production cross section by about two orders of magnitude compared to statistical model calculations. This latter effect is interpreted as mainly due to a delayed onset of compound fission. (orig.)