146Gd and 144Sm excited by the (p,t) reaction on radioactive targets

The (p,t) reaction has been used to study the closed-shell nuclei 146Gd and 144Sm, the former exhibiting some characteristics of a doubly closed shell. Exotic radioactive targets of 148Gd (t1/2 = 75 yr) and 146Sm (t1/2 = 7×10^7 yr) obtained from chemical and isotope separation of irradiated beam-stop material were employed. The ground-state mass excess of 146Gd was measured as being Δu = -76.083(15) MeV and the first excited state is confirmed as being a 3- state at 1.580-MeV excitation energy. Thirteen states were observed in 146Gd and 23 in 144Sm. The pairing-monopole and pairing-quadrupole states in both nuclei are observed for the first time. These levels are higher than systematics would predict, confirming a proton-subshell closure in 146Gd, and are split in 144Sm, indicating a strong interaction between nuclear modes

From elementary school science to graduate school textbooks

The Nuclear Chemistry Division (NCD) at the Lawrence Livermore National Laboratory (LLNL) has a long history of using its resources to enhance the scientific literacy of students at virtually all educational levels, as well as providing for the continued scholarly development of its own staff. The Division has shown a particularly deep concern for motivating young scientific talent, and has a strong record of commitment toward educating and increasing the scientific skills of minorities and women. These activities are carried out by individual, group, or Division initiative and range from simple community involvement and classroom teaching to highly structured and specialized technical training. This report collects and describes the official and unofficial educational activities that have been conducted in the Nuclear Chemistry Division at LLNL during the recent past. These activities serve as a model of what a few dedicated individuals and an enlightened management can contribute to the education of a new generation of scientists and engineers

Special targets for nuclear reaction and spectroscopic studies

Strongly focused and monoenergetic charged-particle beams from modern accelerators and targets fabricated from quantities of isotopically enriched and stable materials are the essential components from many current nuclear physics experiments. Although a large body of this kind of experimental work requires substantial amounts of target material, an important subset of such experiments can be done with as little as a few ..mu..g of material. Experiments where charged particles or electrons can be focused on or transported to a detector are examples of accelerator-based studies which can be made with targets that contain relatively small amounts of material. For these kinds of studies, it then becomes possible to extend the domain of potential target materials to species which are very rare or which are unstable and undergo radioactive decay. At our laboratory during the last ten years, we have made targets for nuclear spectroscopy studies of /sup 152/Eu (13.4y), /sup 154/Eu (8.5y), /sup 249/Bk (320d), /sup 151/Sm (90y), and /sup 148/Gd (75y). We will report our experience with fabricating these and other kinds of stable targets and discuss our plans for preparing additional targets which offer interesting and exciting prospects for future nuclear research studies. 12 refs., 1 fig., 2 tabs

Report to the DOE Nuclear Data Committee, 1985

Progress is reported on the following measurements: the leakage multiplication from hollow beryllium spheres; /sup 6/Li and /sup 7/Li neutron-induced tritium production cross sections at 15 MeV; fast neutron fission yields; /sup 238/U(t,X) cross sections; neutron capture cross sections for /sup 86/ /sup 87/Sr at stellar temperatures; influence of realistic single particle spacings on precompound decay spectra; spontaneous fissions from a source of /sup 260/Md; and excitation functions from proton and deutron bombardment of natural Ti. Progress on the following calculations are reported: using modeled discrete levels; modeling level structures of odd-odd deformed nuclei; test of a phenomenological model of odd-odd deformed nuclei (an ARC study of /sup 176/Lu); absolute dipole gamma-ray strength functions for /sup 176/Lu; Gamow-Teller matrix elements for the /sup 11/B(p,n)/sup 11/C reaction at Ep = 26 MeV; K-distribution for neutron fission of /sup 232/Th; shell model study of the /sup 71/Ga(nu, anti e)/sup 71/Ge neutrino detector; and extension of microscopic models for neutron and proton scattering to inelastic scattering and charge-exchange reactions. Also, the status of the re-evaluation of the /sup 9/Be(n, 2n) reaction is given. (WHK