[en] An international team has solved an essential part of a long-standing discrepancy in the electromagnetic decay heat that occurs after fission of the nuclear fuel component plutonium.

[en] The discovery potential for new proton-emitting isotopes of elements with atomic numbers 35 < Z < 47 in a classical implantation-decay experiment is analyzed. In particular, proton separation energies and half-lives as well as the production and detection methods are discussed for nuclei below 100Sn. Fusion-evaporation reactions studied by means of the Recoil Mass Separator at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory are compared to heavy-ion fragmentation based studies at the National Superconducting Cyclotron Laboratory using the A1900 separator. The I=4 proton emitters 93Ag and 89Rh are identified as primary candidates to be discovered

[en] The decay of extremely neutron-deficient isotope ⁴⁵Fe has been studied by using a new type of gaseous detector in which a technique of optical imaging is used to record tracks of charged particles. The two-proton radioactivity and the beta-decay channels accompanied by proton(s) emission were clearly identified. For the first time, the angular and energy correlations between two protons emitted from the ⁴⁵Fe ground-state were measured. The obtained distributions were confronted with predictions of a three-body model. Studies of beta-decay channels of ⁴⁵Fe provided first unambiguous evidence for the beta-delayed three proton emission

[en] The properties of beta-gamma and beta-delayed neutron emission from ^76-79Cu and ^83-85Ga were measured at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. Selected results on the decay properties of copper isotopes are briefly presented and discussed

[en] An island of isomers have recently been observed on both sides of the N=40 shell below the Ni isotopes. Isomeric states in the 65Fe and 67Fe allow the knowledge of the single particle structure around the g9/2 shell. Moreover, the excitation energy of the first 2+ and 4+ states in the 68Fe have been established by β-γ correlation. The evolution of the structure of the Fe isotopes going far away from the valley of stability is, for the first time, given for N>40

[en] The discovery of the new isotopes 109Xe and 105Te was enabled by the application of a new experimental method using selective pulse shape storage from silicon detectors with digital signal processing electronics. Essential data processing algorithms were developed, which are able to find unique nuclear decay signatures, such as overlapping alpha decay induced signals. An experiment using this method led to the simultaneous detection of isotopes with dramatically different half lives T1/2(109Xe)=13(2) ms and T1/2(105Te)=620(70) ns. The ground state decay energies have been measured to be E (109Xe)=4062(7) keV and E (105Te)=4703(5) keV via observation of correlated events in the decay chain 109Xe 105Te 101Sn

[en] The Nab collaboration will perform a precise measurement of a, the electron-neutrino correlation parameter, and b, the Fierz interference term in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS, using a novel electric/magnetic field spectrometer and detector design. The experiment is aiming at the 10^-3 accuracy level in Δa/a, and will provide an independent measurement of λ = G_A/G_V, the ratio of axial-vector to vector coupling constants of the nucleon. Nab also plans to perform the first ever measurement of b in neutron decay, which will provide an independent limit on the tensor weak coupling.

[en] Production of nuclei above 100Sn in fusion-evaporation reactions between the 58Ni and 54Fe ions was studied by means of Recoil Mass Spectrometer and charge particle detection. The beam energy was varied to optimize the yields for the 2n, 3n and p3n evaporation channels. The experimental results verified the predictions of statistical model code HIVAP. The optimum energy for the 58Ni(4n,108Xe)54Fe reaction channel allowing to reach 108Xe -104Te -100Sn alpha decay chain is deduced as 240 MeV

[en] Proton emitter studies enable precise probing of the composition of the wave function of nuclei beyond the proton dripline. In a decay of proton radioactive odd-odd nuclei excited levels in the (even-Z,odd-N) daughters can be populated allowing us to deduce the properties of single particle neutron states. So far, fine structure in proton emission was observed for only one odd-odd emitter, ¹⁴⁶Tm. The neighboring odd-odd isotope ¹⁴⁴Tm is an obvious candidate to exhibit similar decay pattern. Its decay should be dominated by a large πh_11/2 component present in the ground and isomeric state wavefunction, as it was observed for ¹⁴⁶Tm and ¹⁴⁵Tm. The admixture of the 2⁺ (o)times πf_7/2 component or of the mirror (νh_11/2 πs_1/2) proton-neutron configuration can cause the fine structure in proton emission. Evidence for the proton decay of ¹⁴⁴Tm was found in an experiment at the Recoil Mass Spectrometer at Oak Ridge National Laboratory. The ¹⁴⁴Tm events were found in a weaK. (σ ∼ 10 nb) p5n channel of the fusion reaction of ⁵⁸Ni beam at 340 MeV on a ⁹²Mo target. The observed decay energy of about 1.8 MeV and the half-life of the order of ∼ 1 (micro)s suggest proton emission from the dominant πh_11/2 part of the wave function. The detection of this very short proton emitter was made possible by use of a double-sided silicon strip detector connected to a fast Digital-Signal-Processing-based acquisition system

[en] Production of nuclei above ¹⁰⁰Sn in fusion-evaporation reactions between ⁵⁸Ni beam and ⁵⁴Fe target was investigated. Reaction products were studied at Oak Ridge by means of the Recoil Mass Spectrometer and charged particle detection. The yields for the 2n, pn, 3n, p2n, 2pn, p3n and 2p2n fusion-evaporation channels were measured. These experimental results were used to verify the predictions of the statistical model code HIVAP. The optimum energy for the ⁵⁴Fe(⁵⁸Ni,4n)¹⁰⁸Xe reaction allowing detection of the ¹⁰⁸Xe-¹⁰⁴Te-¹⁰⁰Sn alpha decay chain is deduced as 240 MeV