[en] The collective properties for the Z approximately greater than 50 transition region were studied via heavy-ion induced γ-ray experiments using ⁶⁷Li, ¹⁰B, ¹²¹³C, ¹⁴N, and ¹⁶O beams. The high-spin systematics for odd-mass ^113-125Sb (Z = 51), ^115-127I (Z = 53), ^119-133Cs (Z = 55), and ^125-127La (Z = 57) nuclei were obtained. Two collective features were observed, the first being systematic ΔJ = 1 bands built on low-lying 1g/sub 9/2/ proton-hole states, and the second systematic ΔJ = 2 bands built on 2d/sub 5/2/, 1g/sub 7/2/, and 1h/sub 11/2/ quasi-proton states. Unexpected properties were observed. 27 references

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[en] The high-spin structure of ¹¹¹In has been investigated with γ-ray spectroscopic methods using the ⁹⁶Zr(¹⁹F,4n) reaction. A thin target experiment using an 85 MeV beam provided by the Chalk River TASCC facility yielded 50 million γ - γ coincidence events from the 8π spectrometer, whereas a backed target experiment using a 72 MeV beam provided by the SUNY Stony Brook LINAC facility yielded 150 million events from the Stony Brook BGO-suppressed Ge spectrometer. As initial report on these ¹¹¹In data presented the discovery of the first πh_11/2 intruder band found below the Z=50 shell gap. A complete level scheme has now been established utilizing the full data set in the form of symmetrized and angular correlation (DCO) matrices. Decoupled and strongly coupled bands have been observed with possible interpretations involving, respectively, the πg_7/2 circle-times πg^-2_9/2 configuration and the πg^-1_9/2 orbital coupled to the deformed 2p2h core state of ¹¹²Sn

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[en] The nucleus ¹¹⁶Te has been studied using the reaction ⁶⁴Ni(⁵⁶Fe,2p2n) at a beam energy of 236 MeV. Both self-supporting and backed target experiments were performed at the (EI) GAMMASPHERE array equipped with 36 suppressed Ge detectors. A total of 2 G and 0.1G three- or higher fold events were collected respectively, with a yield of ∼15% in the 2p2n channel. This experiment endeavored to search in ¹¹⁶Te for novel intruder rotational bands involving proton particle-hole excitations across the Z = 50 closed shell gap. These intruder bands have the unique characteristic of gradually decreasing dynamic moments of inertia with increasing spin to unusually low values, a behavior that has been interpreted as evidence for open-quotes softclose quotes band termination in which the nuclear shape gradually evolves from collective prolate to noncollective oblate. Two such intruder bands, reaching spins of 26ℎ and 40ℎ, have been extracted from these data, both of which are connected to known low-lying states in ¹¹⁶Te

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[en] An experiment was performed with GAMMASPHERE at the LBL, to populate high-spin states in the Z=51 isotope ¹⁰⁹Sb. The reaction ⁵⁴Fe(⁵⁸Ni,3p) at 243 MeV with multiple thin targets was used. Previous work at Chalk River had identified three ΔI=2 rotational bands, which extend to rotational frequencies up to 1.4 MeV. The forward-backward detector configuration at CAMMASPHERE provided 400 x 10⁶ events of high resolution data which were sorted into a γ-γ-γ cube. The known bands were extended to even higher rotational frequencies, and a new decoupled band was identified. The dynamic moments of inertia of these bands decrease to very low values at high rotational frequencies. The analysis of these data is currently in progress

[en] Lifetime measurements are discussed, concentrating on the electronic technique, the recoil distance method (RDM), and the Doppler shift attenuation method (DSAM). A brief review of several indirect timing techniques is given, and their specific advantages and applicability are considered. The relationship between lifetimes of nuclear states and the nuclear structure information obtained from them is examined. A short discussion of channeling and microwave methods of lifetime measurement is presented. (23 figures, 171 references) (U.S.)