[en] Experiments using the Daresbury Recoil Mass Separator have identified microsecond isomers in the exotic N = 82, 83 nuclei ¹⁵³Yb, ¹⁵³Lu, ¹⁵⁴Hf, and have established their decay schemes. The results for ¹⁵³Lu and ¹⁵⁴Hf, together with those for lighter N = 82 isotones, provide an outstanding illustration of the dependence of E2 transition rates between Jⁿ states on the subshell occupation, and demonstrate that half-filling of the πh_11/2 subshell in the N = 82 series occurs just below Z = 71 ¹⁵³Lu. The result of the isomer in the even-odd N = 83 nucleus ¹⁵³Yb shows that the isomerism is due to a low-energy E2 transition rather than an E3 transition as in lighter N = 83 even-odd isotones, which is another consequence of the πh_11/2 subshell being about half-filled. Furthermore, the long-lived isomer observed in the odd-odd N = 83 nucleus ¹⁵⁴Lu also reflects that the πh_11/2 subshell is close to being half-filled. 23 refs., 12 figs., 4 tabs

[en] Using mass-separated sources, the β-decay properties of /sup 154/Lu and /sup 154/Yb were investigated. Limits of /sup 154/Lu decay to the first 8⁺ and 6⁺ levels in /sup 154/Yb suggest a 7⁺ spin for the odd-odd parent; also delayed proton emission and an indication of delayed α-particle emission were observed to follow /sup 154/Lu β decay. The β-decay branch of the α-emitting nucleus /sup 154/Yb was identified for the first time by the observation of one intense 133.2-keV γ ray. This transition deexcites a 1⁺ 133.2-keV level in /sup 154/Tm which is fed by an allowed 0⁺→1⁺β transition with a logft value of 3.6 +- 0.3

[en] Microsecond isomers in the very proton-rich N=82 nuclei ¹⁵³Lu and ¹⁵⁴Hf have been identified by γ-ray spectroscopy following mass analysis of ¹⁰²Pd +245 MeV ⁵⁴Fe reaction products using the Daresbury Recoil Separator. The decays of the isomers, interpreted as (πh_11/2)ⁿ states, are characterized. Examination of reduced E2 transition rates between (πh_11/2)ⁿ states in the N=82 isotones indicates that the half-filling of the πh_11/2 subshell occurs just below Z=71

[en] The experimental results from the various reaction and decay studies leading to nuclides in the A = 154 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties

[en] The experimental results from the various reaction and decay studies leading to nuclides in the A = 154 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties, for the nuclides from Ce(Z = 58) through Hf(Z = 72). This evaluation replaces that of 1998Re22, which appeared in Nuclear Data Sheets 85, 171 (1998).

[en] The experimental results from the various reaction and decay studies leading to nuclides in the A = 154 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties. Data available prior to July 1998 have been evaluated

[en] We have studied β decays, Q values and nuclear masses of very proton rich nuclei with neutron numbers around the shell closure 82 because of the following aspects: very fast Gamow-Teller β transitions are observed in these nuclei and the dependence of the corresponding transition probabilities on the number of the envolved nucleons is beautifully described in the shell model, an effect of the proton subshell closure 64 to the nuclear masses can be studied with the derived masses, the investigated nuclei are endpoints of α-decay chains. By this way, many nuclear masses can be obtained and mass formulae can be tested far away from the valley of stability and many of the considered β transitions have simple decay schemes and via the k/β ratio measurement there is favourable method to determine nuclear Q values. (orig.)

[en] Measurements of γ-rays from mass analyzed nuclear recoils produced in the ¹⁰²Pd+⁵⁴Fe reaction at 245 MeV have allowed us to characterize the decay of a 35 μs isomer in ¹⁵⁴Lu. The rates of E2 transitions de-exciting isomeric levels in proton-rich N=82, 83 isotones are discussed. (orig.)

No abstract available

[en] Microsecond isomers in the exotic proton-rich N=82, 83 nuclei ¹⁵³Yb, ¹⁵³Lu, ¹⁵⁴Lu and ¹⁵⁴Hf have been identified by γ-ray spectroscopy following mass analysis of ¹⁰²Pd+245 MeV ⁵⁴Fe reaction products using the Daresbury Recoil Separator. The decays of the isomers, interpreted as πhⁿ_11/2 and πhⁿ_11/2νf_7/2 states, are characterized. The reduced E2 transition rates indicate that half-filling of the πh_11/2 subshell occurs just below Z=71, and results for the N=83 odd-odd isotones are also consistent with this finding. (orig.)