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New level schemes of odd-Z99,101Y (Z = 39) and 101,105Nb (Z = 41) are established based on the measurement of prompt gamma rays from the fission of 252Cf at Gammasphere. Bands of π5/2+[422], π5/2−[303] and π3/2−[301] are observed and extended to provide spectroscopic information concerning nuclear shapes in this important odd-Z region. In combination with the level structure of the odd-Z Tc (Z = 43), Rh (Z = 45) and the neighbouring even-Z isotopes the level systematics, signature splittings and kinematic and dynamic moments of inertia of the bands in the Y and Nb isotopes are discussed in terms of shape transition and triaxiality. The pronounced difference observed in the signature splittings between Y and Tc, Rh isotopes is interpreted as evidence of the axially symmetric deformed shape in the Y isotopes, and, as previously reported, large and near maximum triaxiality in Tc–Rh isotopes. The likely lowering of crossing frequencies of the ground-state bands in Tc and Rh isotones in comparison with those in Y isotones also implies a shape transition from axially symmetric deformed shapes in Y nuclei to triaxiality in Tc and Rh isotones. Triaxial-rotor-plus-particle model calculations strongly support a pure axially symmetric shape with large quadrupole deformation in Y isotopes. The model calculations yielded γ values ranging from −19° to −13° for the 5/2+[422] ground-state bands of 101,103,105Nb and of −5° for the two negative-parity bands in 101Nb. The fact that Nb isotopes have intermediate values of signature splitting and band crossing frequencies between those of Y and Tc, Rh isotopes is interpreted as that the Nb isotopes are transitional nuclei with regard to triaxial deformation. A correlation of quadrupole deformations and of triaxiality is seen in the neutron-rich nuclei with Z = 39–45.

From multiparameter data obtained at Lawrence Berkeley National Laboratory, the integral characteristics of the prompt γ-ray emission were extracted for tripartition of ²⁵²Cf with He, Be and C being the third light charged particle. We used multifold γ-ray coincidence spectra for the determination of γ-ray multiplicities assuming a Gaussian distribution for γ-ray multiplicity. The multiplicity distribution characteristics, i.e. mean multiplicity and its dispersion were obtained by minimizing with respect to the calculated values of probabilities of multifold γ-ray coincidences using a combinatoric method. Comparison with the known experimental data from binary fission was made. Further, we investigated dependencies of the mean γ-ray multiplicity on the kinetic energy of the light charged particle. The mean γ-ray multiplicity for He ternary fission is found to increase rapidly with increasing kinetic energy of He in the region less than 11 MeV and then decrease slowly with increasing kinetic energy of He. The anomalous behaviour of γ-ray emission is discussed. The mean γ-ray multiplicity was determined for the first time for Be and C ternary fission. For Be, the γ-ray multiplicity as a function of kinetic energy was obtained as well.

New excited states built on the 11/2⁻ isomeric states are identified in neutron-rich ^121,123Cd, respectively, with gammasphere by measuring three-and higher-fold prompt coincidences following the spontaneous fission of ²⁵²Cf. The new data suggests that the 11/2⁻ isomers in the odd-A Cd isotopes with N ≥ 75 have spherical shape similar to those in Te. It is suggested that the backbending observed at ℏω ≈ 0.445 MeV in ¹²¹Cd is because of the alignment of the h_11/2 neutron pair.

We have carried out a series of experiments to test the recently claimed observations of cold fusion. In a first experiment, we used an electrochemical cell with a Pd wire cathode. Neutrons were detected by the1H(n,?) photons from surrounding water and paraffin. In a second experiment, two vacuum-cast Pd disks were the cathodes in “twin” cells, one with H2O, and the other with D2O. The two cells were shuttled every 24 hours between similar detector setups, equipped with neutron, ?- and x-ray detectors. A third experiment was designed to measure production of charged particles, using an Si surface barrier detector viewing the back of a 76-µm thick Pd foil cathode. No statistically-significant evidence of nuclear fusion has been obtained in any of these experiments, either in steady-state operation or in transient response to a variety of perturbations. Upper bounds on the rate of various postulated fusion processes were set including <2×10-23 neutrons (dd pair)-1 s-1 for the d(d,n)3He reaction and <6×10-25 protons (dd pair)-1 s-1 for the d(d,p)3H reaction (2s level). Chemical analysis of our electrolytes revealed no anomalous increase in3H concentrations. (PACS numbers: 82.45.+z,29.30.-h,29.70.-e,25.45.-z).

A model of239Pu with decoupled neutron is used for theoretical calculations of rotational population patterns in heavy ion inelastic scattering and one-neutron transfer reactions. The system treated is90Zr on239Pu at the near-barrier energy of 500 MeV and backscattering angles of 180° and 140°. The influence of the complex nuclear optical potential is seen to be very strong, and the Nilsson wave function of the odd neutron produces a distinctive pattern in the transfer reaction.

A model of energy gain induced by fast ignition of thermonuclear burn in compressed deuterium-tritium fuel, is used to show the potential for 300× gain with a driver energy of 1 MJ, if the National Ignition Facility (NIF) were to be adapted for fast ignition. The physics of fast ignition has been studied using a petawatt laser facility at the Lawrence Livermore National Laboratory. Laser plasma interaction in a preformed plasma on a solid target leads to relativistic self-focusing evidenced by x-ray images. Absorption of the laser radiation transfers energy to an intense source of relativistic electrons. Good conversion efficiency into a wide angular distribution is reported. Heating by the electrons in solid density CD2produces 0.5 to 1 keV temperature, inferred from the D-D thermo-nuclear neutron yield.

117Te has been studied via82Se(40Ar,5n)117Te, and a new, substantially extended level scheme is proposed to I˜53/2. Our TRS calculations suggest rotational bands, but with an experimental sensitivity of ˜2%, we see none. Our results differ from those of Sharma, et al, who report two isolated E2 bands. We find them less band-like, being joined at the top and changed in content and order. We suggest a noncollective oblate shape for a new 39/2- level.

This paper presents results of experiments aimed at producing long-lived superheavy elements located near the spherical shells at Z≥114 and N≥172 in the reactions of neutron-rich isotopes 242,244Pu, 243Am, 245,248Cm and 249Cf with 48Ca projectiles. The decay properties of the synthesized nuclei are consistent with the consecutive α-decays originating in the decays of parent nuclides 286,287,288,289114, 287,288115, 290,291,293116 and 294118 produced in the 2n- to 5n-evaporation channels. The present observations can be considered to be experimental evidence of the existence of the “island of stability” of superheavy elements.