[en] Beyond Fe, there is a class of 35 proton-rich nuclides, between ⁷⁴Se and ¹⁹⁶Hg, called p-nuclei. They are by passed by the s and r neutron capture processes and are typically 10–1000 times less abundant than the s- and/or r-isotopes in the solar system. There is a typical abundance of ~ 1% for lighter nuclei with 34 ≤ Z ≤ 50 and 0.01-0.3% for medium and heavier nuclei with an atomic number >50. Generally, the abundance of p-nuclei decreases with an increase in atomic number, but for neutron magic p-nuclei ⁹²Mo and ¹⁴⁴Sm, it is 14.52% and 3.08%, respectively. So, the study of these nuclei is important to understand why they are more abundant. For this reason, more detailed and precise information about the reaction cross-section in the astrophysical energy region is extremely important. In this article, the first step of any reaction, which is target preparation, is discussed. Many isotopically enriched targets are more easily available in oxide powder form. Those target materials are not suitable for target preparation with an e-beam, thermal processing, or sputtering. Apart from that, target material waste in these techniques is one of the major disadvantages for expensive materials. For all of these reasons, samarium targets made from Sm₂O₃ powder were created using the molecular deposition technique. To prepare targets with the least amount of material loss, a simple, low cost setup was used. Natural and 144-enriched samarium targets with thicknesses ranging from 100 to 400 μg/cm₂ have been successfully prepared using this method. (author)

[en] Angular distributions of gamma rays from the reaction ⁹²Mo(n,n'γ) with respect to the axis of the fast-reactor-neutron beam were measured. The known scheme of levels and gamma transitions in ⁹²Mo was supplemented. The multipole-mixture parameters δ were found for gamma transitions between levels. The relationship between the parameters δ and the structure of excited states of ⁹²Mo is discussed.

[en] With an improved Boltzmann-Uehling-Uhlenbeck model, the deformation energy surfaces in reactions leading to the formation of toroidal and bubble nuclei are examined for central ⁹²Mo+⁹²Mo collisions. We found that the potential maximum, or the fragmentation barrier, occurs at times close to the times when these exotic shapes are formed. However, due to the dynamics of large amplitude compression and expansion, the fragmentation barriers are significantly higher than those estimated from the liquid-drop models

[en] The heavy odd-odd N=Z nuclei ⁷⁴Rb, ⁷⁸Y, ⁸²Nb, ⁸⁶Tc have been produced at GANIL by fragmentation of a 60 MeV/u ⁹²Mo beam on a natural nickel target. The species of interest were selected and identified by their energy loss in a silicon detector and their time of flight through the LISE spectrometer. The ions were implanted in a silicon strip detector in which their β-decay was observed. The measured half-lives for ⁷⁸Y, ⁸²Nb, ⁸⁶Tc correspond to superallowed transitions and may sign Fermi transitions on the basis of log ft values. Our experimental results pave the way for further and more precise measurements of these nuclei. (author)

[en] The structural properties of nuclei at or close to the proton drip line around A∼80 have been studied following a series of experiments using the fragmentation of ⁹²Mo at a beam energy of 60 MeV per nucleon on a selection of natural nickel targets. The fragments were identified using the LISE3 spectrometer, with additional information on gamma-ray decays from isomeric states determined using a high-efficiency array of hyper-pure germanium detectors at the final focus of the spectrometer. This body of work has enabled the study of a number of pertinent structural phenomena in this region, the highlights of which include the determination of the proton drip-line around A∼80, examples of prolate-oblate shape-coexistence, the observation of an isomeric decay in the heaviest N=Z system yet where gamma-decays have been observed (⁸⁶Tc) and β+ decay studies in the heaviest nuclei where Fermi Superallowed β+ -decays have been deduced. (author)

No abstract available

[en] Multifragmentation, following the formation of toroidal and bubble nuclei, is observed with an improved Boltzmann-Uehling-Uhlenbeck (BUU) model for central ⁹²Mo + ⁹²Mo collisions. Guided by our BUU model, we propose two signatures: (1) because of the geometries of bubbles and toroids and because of the cold breakup at low temperatures, we predict enhanced cross sections for fragments with nearly-equal masses at small center-of-mass energies. (2) the coplanarity of these nearly-equal fragments could carry important information concerning the geometry of the sources. This in turn, could provide information about the stiffness of the equation of state

[en] With the use of a fragment mass analyzer, the α decay of ¹⁸⁰Tl was identified in ⁹²Mo bombardments of ⁹⁰Zr. At least three α transitions were observed but on the basis of the data obtained it was not possible to conclude if they originate from one or more levels in ¹⁸⁰Tl. In the same irradiations a new α group was also identified in ¹⁷⁹Tl^m decay. Based on energy and half-life systematics, it appears that ¹⁷⁹Tl^m, in contrast to the isomers in heavier odd-A Tl nuclei, is not the h_9/2 intruder level but rather the h_11/2 proton state. copyright 1998 The American Physical Society

[en] Fragmentation products from a ⁹²Mo beam on a natural nickel target have been used to study structural properties of the very neutron deficient nuclei around N∼Z∼40. We present the first observation of isomeric decays in the T_Z=1 systems ⁷⁴Kr, ⁸⁰Y and ⁸⁴Nb. The isomer in ⁷⁴Kr is interpreted as the hindered decay from an excited 0⁺ state, confirming the prediction of prolate/oblate shape coexistence in this nucleus. Transitions from states below an isomer in the N=Z nucleus ⁸⁶Tc have also been tentatively identified, making this the heaviest N=Z system for which decays from excited states have been observed. In addition, we have obtained the first conclusive evidence for the existence of the T_Z=1/2 isotopes ⁷⁷Y, ⁷⁹Zr and ⁸³Mo. The data for ⁷⁷Y is of particular interest in light of the reported instability in the lighter odd-Z, T_Z =-1/2 systems ⁶⁹Br and ⁷³Rb. (author)

No abstract available