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Excited states in ${}^{73,75}\mathrm{Ni}$ were investigated through the $\ensuremath{\beta}$ decay of ${}^{73,75}\mathrm{Co}$ in an experiment performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). The experimental results extended the level scheme of $^{73}\mathrm{Ni}$ to 3.2-MeV excitation energy and provided the experimental information on excited states in $^{75}\mathrm{Ni}$. The $\ensuremath{\beta}$-delayed neutron branching ratio for $^{73}\mathrm{Co}$ was obtained. The experimental results are discussed in comparison with shell-model calculations.

The most remote isotope from the proton dripline (by 4 atomic mass units) has been observed: ^{31}K. It is unbound with respect to three-proton (3p) emission, and its decays have been detected in flight by measuring the trajectories of all decay products using microstrip detectors. The 3p emission processes have been studied by the means of angular correlations of ^{28}S+3p and the respective decay vertices. The energies of the previously unknown ground and excited states of ^{31}K have been determined. This provides its 3p separation energy value S_{3p} of -4.6(2) MeV. Upper half-life limits of 10 ps of the observed ^{31}K states have been derived from distributions of the measured decay vertices.

Excited states in Sn-133 were investigated through the beta decay of In-133 at the ISOLDE facility. The ISOLDE Resonance Ionization Laser Ion Source (RILIS) provided isomer-selective ionization for In-133, allowing us to study separately, and in detail, the beta-decay branch of In-133 J(pi)= (9/2(+)) ground state and its J(pi) = (1/2(-)) isomer.Thanks to the large spin difference of the two beta-decaying states of In-133, it is possible to investigate separately the lower and higher spin states in the daughter, Sn-133, and thus to probe independently different single-particle and single-hole levels. We report here new gamma transitions observed in the decay of In-133, including those assigned to the deexcitation of the neutron-unbound states.

Decay of $^{85}\mathrm{Ga}$ was studied by means of $\ensuremath{\beta}$-neutron-$\ensuremath{\gamma}$ spectroscopy. A pure beam of $^{85}\mathrm{Ga}$ was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and a high-resolution electromagnetic separator. The $\ensuremath{\beta}$-delayed neutron emission probability was measured for the first time, yielding 70(5)%. An upper limit of 0.1% for $\ensuremath{\beta}$-delayed two-neutron emission was also experimentally established for the first time. A detailed decay scheme including absolute $\ensuremath{\gamma}$-ray intensities was obtained. Results are compared with theoretical $\ensuremath{\beta}$-delayed emission models.

This work was supported in part by the Helmholtz International Center for FAIR (HIC for FAIR), the Helmholtz Association (grant IK-RU-002), the Russian Ministry of Education and Science (grant No. NSh- 932.2014.2), the Russian Science Foundation (grant No. 17-12-01367), the Polish National Science Center (Contract No. UMO-2011/01/B/ST2/01943), the Polish Ministry of Science and Higher Education (Grant No. 0079/DIA/2014/43,Grant Diamentowy), the Helmholtz- CAS Joint Research Group (grant HCJRG-108), the FPA2009-08848 contract (MICINN, Spain), the Justus- Liebig-Universit¨at Giesen (JLU) and GSI under the JLUGSI strategic Helmholtz partnership agreement. This article is a part of PhD thesis of X.-D. Xu. The authors acknowledge the help of D. Kostyleva in the preparation of the manuscript.

The $\ensuremath{\beta}$-decay properties of the very neutron-rich nucleus $^{85}\mathrm{Ge}$, produced in the proton-induced fission of $^{238}\mathrm{U}$, were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The level scheme of $\phantom{\rule{0.16em}{0ex}}_{33}^{85}\mathrm{As}_{52}$ populated in $^{85}\mathrm{Ge}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}\ensuremath{\gamma}$ decay was reconstructed and compared to shell-model calculations. The investigation of the systematics of low-energy levels in $N=52$ isotones together with shell-model analysis allowed us to provide an estimate of the low-energy structure of the more exotic $N=52$ isotone $^{81}\mathrm{Cu}$.

Delayed emission of protons following β decay of neutron deficient nuclei P26 and S27 was investigated at the ACCULINNA separator in the Flerov Laboratory of Nuclear Reactions at Dubna. Ions of interest, identified in flight, were implanted into the active volume of the gaseous optical time projection chamber, which allowed us to record tracks of charged particles emitted in the decay. Total branching ratios for β-delayed proton emission and for β-delayed two-proton emission were determined. In addition, energy spectra for delayed protons below 2 MeV were established. Our findings for P26 agree with results of previous experiments. In the case of S27, however, the observed probability of delayed proton emission is an order of magnitude larger than reported in literature. Two new strong proton transitions were identified representing decays of the first two excited states of P27 to the ground state of Si26. The probability ratio of γ-to-proton emission from these states is discussed.

$\ensuremath{\beta}$ decay of neutron-rich nuclide $^{94}\mathrm{Kr}$ was reinvestigated by means of a high resolution on-line mass separator and $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ spectroscopy. In total 22 $\ensuremath{\gamma}$-ray transitions were assigned to the decay of $^{94}\mathrm{Kr}$, and a new isomeric state was identified. The new information allows us to build detailed levels systematics in a chain of odd-odd rubidium isotopes and draw conclusions on nuclear structure for some of the observed states. The discussed level structure affects the evolution of $\ensuremath{\beta}$-decay half-lives for neutron-rich selenium, krypton, and strontium isotopes.

The excitation of the dynamical dipole mode along the fusion path was investigated for the first time in the formation of a heavy compound nucleus in the $A\ensuremath{\sim}190$ mass region. The compound nucleus was formed at identical conditions of excitation energy and spin from two entrance channels: the charge-asymmetric $^{40}\mathrm{Ca}+^{152}\mathrm{Sm}$ and the nearly charge-symmetric $^{48}\mathrm{Ca}+^{144}\mathrm{Sm}$ at ${E}_{\text{lab}}=11$ and 10.1 MeV/nucleon, respectively. High-energy $\ensuremath{\gamma}$ rays and light charged particles were measured in coincidence with evaporation residues by means of the MEDEA multidetector array (Laboratori Nazionali del Sud, Italy) coupled to four parallel plate avalanche counters. The charged particle multiplicity spectra and angular distributions were used to pin down the average excitation energy, the average mass, and the average charge of the compound nucleus. The $\ensuremath{\gamma}$-ray multiplicity spectrum and angular distribution related to the nearly charge-symmetric channel were employed to obtain new data on the giant dipole resonance in the compound nucleus. The dynamical dipole mode excitation in the charge-asymmetric channel was evidenced, in a model-independent way, by comparing the $\ensuremath{\gamma}$-ray multiplicity spectra and angular distributions of the two entrance channels with each other. Calculations of the dynamical dipole mode in the $^{40}\mathrm{Ca}+^{152}\mathrm{Sm}$ channel, based on a collective bremsstrahlung analysis of the reaction dynamics, are presented. Possible interesting implications in the superheavy-element quest are discussed.

Decays of neutron-rich nuclei $^{82,83}\mathrm{Zn}$ and $^{82,83}\mathrm{Ga}$ produced in proton-induced fission of $^{238}\mathrm{U}$ were studied at the Holifield Radioactive Ion Beam Facility using on-line mass separation and $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\gamma}$ spectroscopy techniques. New $\ensuremath{\gamma}$-ray transitions were identified and level schemes, which include states at high excitation energies in the range between 3--7 MeV were constructed. These high-energy levels were identified to be populated through allowed Gamow-Teller $\ensuremath{\beta}$ transitions, and their structure was interpreted with new shell-model calculations. A $\ensuremath{\beta}$-delayed neutron branching ratio of $69\ifmmode\pm\else\textpm\fi{}7%$ was deduced for $^{82}\mathrm{Zn}$ and revised $\ensuremath{\beta}$-decay half-life values of $^{82}\mathrm{Zn}$ [155(17)(20) ms] and $^{83}\mathrm{Zn}$ [122(28) ms] were determined.

The $\ensuremath{\beta}$-decay properties of neutron-rich $^{87}\mathrm{As}$ produced in the proton-induced fission of $^{238}\mathrm{U}$ were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The low-energy excited states in $N=53 ^{87}\mathrm{Se}$ and $N=52 ^{86}\mathrm{Se}$ were identified through $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\gamma}$ and $\ensuremath{\beta}$-delayed neutron-$\ensuremath{\gamma}$ decay of $^{87}\mathrm{As}$, respectively. The experimental systematics of low-energy levels of $N=53$ isotones, $Z=34 ^{87}\mathrm{Se},$ and $Z=32 ^{85}\mathrm{Ge}$, and along with an analysis of shell-model calculations, allow us to discuss the main features of excited states expected for the next $N=53$ isotone, $^{83}\mathrm{Zn}$.

The $\ensuremath{\beta}$-decay properties of very neutron rich nuclei $^{86}\mathrm{Ge}$ and $^{86}\mathrm{As}$ were measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. Spectroscopic information on new excited states in $^{86}\mathrm{As}$ and in $^{86}\mathrm{Se}$ was obtained and is interpreted within an advanced shell model approach. These calculations, previously explaining well the structure of $^{84}\mathrm{Ge}$ and $^{85}\mathrm{Ge}$, are not able to reproduce all the experimentally determined features of the measured level schemes of $^{86}\mathrm{As}$ and $^{86}\mathrm{Se}$. The Gamow-Teller decay of $^{86}\mathrm{Ge}$ and $^{86}\mathrm{As}$ is also investigated in a shell-model framework. The fission yield for $^{86}\mathrm{Ge}$ is discussed.

Previously unknown isotopes Ar-30 and Cl-29 have been identified by measurement of the trajectories of their in-flight decay products S-28 + p + p and S-28 + p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of Ar-30 and Cl-29 were found at 2.25(-0.10)(+0.15) and 1.8 +/- 0.1 MeV above the two-and one-proton thresholds, respectively. The lowest states in Ar-30 and Cl-29 point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the Ar-30 ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of Ar-30*(2(+)) has been obtained by detecting two decay branches into the ground and first-excited states of the S-28 fragment.

The energy and angular distributions of $^{3}\mathrm{He}$ and $^{4}\mathrm{He}$ ions produced in the $^{7}\mathrm{Be}\phantom{\rule{4pt}{0ex}}+\phantom{\rule{4pt}{0ex}}^{58}\mathrm{Ni}$ reaction at a bombarding energy of 22 MeV have been measured for the first time. The yield of the heavier helium isotope was four to five times more abundant than that of its lighter counterpart, ruling out the possibility that in this energy range the $^{7}\mathrm{Be}$ reaction dynamics is dominated by the exclusive breakup process $^{7}\mathrm{Be}\phantom{\rule{4pt}{0ex}}\ensuremath{\rightarrow}{\phantom{\rule{4pt}{0ex}}}^{3}\mathrm{He}\phantom{\rule{4pt}{0ex}}+\phantom{\rule{4pt}{0ex}}^{4}\mathrm{He}$ (${S}_{\ensuremath{\alpha}}=1.586$ MeV). Extensive kinematic and theoretical calculations suggest that the $^{3}\mathrm{He}$ ions mostly originate from the $^{4}\mathrm{He}$-stripping process and the $^{4}\mathrm{He}$ production is mainly triggered by the fusion-evaporation channel. The role played by the breakup, $^{3}\mathrm{He}$-stripping, $1n$-stripping, and $1n$-pickup processes is also discussed.

The rare $\ensuremath{\beta}$-decay channel of $^{6}\mathrm{He}$ into the $\ensuremath{\alpha}+d$ continuum was investigated at the REX-ISOLDE facility. Bunches of postaccelerated $^{6}\mathrm{He}$ ions were implanted into the optical time projection chamber (OTPC), where the decays with emission of charged particles were recorded. This novel technique allowed us to extend the low-energy end of the spectrum down to 150 keV in $\ensuremath{\alpha}+d$ center of mass, corresponding to a deuteron energy of 100 keV. The branching ratio for this process amounts to $[2.78\ifmmode\pm\else\textpm\fi{}0.07(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.17(\mathrm{sys})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. The shape of the spectrum is found to be in a good agreement with a three-body model, while the total intensity is about 20% larger than the predicted one.

In an experiment at the A1900 spectrometer of the National Superconducting Cyclotron Laboratory at Michigan State University the new isotope $^{59}\mathrm{Ge}$ was identified and the cross section for production of the most neutron-deficient $^{59\ensuremath{-}62}\mathrm{Ge}$ isotopes in the fragmentation of a $^{78}\mathrm{Kr}$ beam at 150 MeV/nucleon measured. This experimental information is relevant for the hunt of new two-proton emitters in the region above the doubly-magic $^{48}\mathrm{Ni}$.

The $\ensuremath{\beta}$ decay of $^{31}\mathrm{Ar}$, produced by fragmentation of an $^{36}\mathrm{Ar}$ beam at 880 MeV/nucleon, was investigated. Identified ions of $^{31}\mathrm{Ar}$ were stopped in a gaseous time projection chamber with optical readout allowing us to record decay events with emission of protons. In addition to $\ensuremath{\beta}$-delayed emission of one and two protons we clearly observed the $\ensuremath{\beta}$-delayed three-proton branch. The branching ratio for this channel in $^{31}\mathrm{Ar}$ is found to be $0.07\ifmmode\pm\else\textpm\fi{}0.02$%.

The excited states of odd-odd $^{82}\mathrm{As}$ are studied in the $\ensuremath{\beta}$ decay of $^{82}\mathrm{Ge}$. An isotopically pure beam of $^{83}\mathrm{Ga}$ was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and high-resolution electromagnetic separation. The atoms of $^{82}\mathrm{Ge}$ are created after $\ensuremath{\beta}$-delayed neutron emission in the decay of $^{83}\mathrm{Ga}$. The number of $^{82}\mathrm{Ge}$ atoms is found by normalization to the 1348-keV $\ensuremath{\gamma}$ ray. Detailed analysis of the decay scheme is compared with shell-model calculations with several commonly used $fpg$ shell interactions.

Recent observations of $^{6}\mathrm{Li}$ in metal poor stars suggest a large production of this isotope during big bang nucleosynthesis (BBN). In standard BBN calculations, the $^{2}\mathrm{H}(\ensuremath{\alpha},\ensuremath{\gamma})^{6}\mathrm{Li}$ reaction dominates $^{6}\mathrm{Li}$ production. This reaction has never been measured inside the BBN energy region because its cross section drops exponentially at low energy and because the electric dipole transition is strongly suppressed for the isoscalar particles $^{2}\mathrm{H}$ and $\ensuremath{\alpha}$ at energies below the Coulomb barrier. Indirect measurements using the Coulomb dissociation of $^{6}\mathrm{Li}$ only give upper limits owing to the dominance of nuclear breakup processes. Here, we report on the results of the first measurement of the $^{2}\mathrm{H}(\ensuremath{\alpha},\ensuremath{\gamma})^{6}\mathrm{Li}$ cross section at big bang energies. The experiment was performed deep underground at the LUNA 400 kV accelerator in Gran Sasso, Italy. The primordial $^{6}\mathrm{Li}/^{7}\mathrm{Li}$ isotopic abundance ratio has been determined to be $(1.5\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, from our experimental data and standard BBN theory. The much higher $^{6}\mathrm{Li}/^{7}\mathrm{Li}$ values reported for halo stars will likely require a nonstandard physics explanation, as discussed in the literature.

Results of decay spectroscopy on nuclei in the vicinity of the doubly magic $^{48}\mathrm{Ni}$ are presented. The measurements were performed with a time projection chamber with optical readout which records tracks of ions and protons in the gaseous volume. Six decays of $^{48}\mathrm{Ni}$, including four events of two-proton ground-state radioactivity, were recorded. An advanced reconstruction procedure yielded the $2p$ decay energy for $^{48}\mathrm{Ni}$ of ${Q}_{2p}=1.29(4)$ MeV. In addition, the energy spectra of $\ensuremath{\beta}$-delayed protons emitted in the decays of $^{44}\mathrm{Cr}$ and $^{46}\mathrm{Fe}$, as well as half-lives and branching ratios, were determined. The results were found to be consistent with the previous measurements made with Si detectors. A new proton line in the decay of $^{44}\mathrm{Cr}$ corresponding to the decay energy of 760 keV is reported. The first evidence for the $\ensuremath{\beta}2p$ decay of $^{46}\mathrm{Fe}$, based on one clear event, is shown.

The $\ensuremath{\beta}$-decay properties of neutron-rich ${}^{85}$Ga produced in proton-induced fission of ${}^{238}$U were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. Data consisted of $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ and $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences were collected at the Low-energy Radioactive Ion Beam Spectroscopy Station after high-resolution on-line mass separation. For the first time, the excited states in the $N=53$ isotone ${}^{85}$Ge were established from $\ensuremath{\beta}$-delayed $\ensuremath{\gamma}$ decay of ${}^{85}$Ga. The level scheme of the $N=52$ isotone ${}^{84}$Ge was improved and includes now 0${}^{+}$, 2${}^{+}$, (2)${}^{+}$, 4${}^{+}$, and (0)${}^{+}$ states populated in the $\ensuremath{\beta}$-delayed-neutron-$\ensuremath{\gamma}$ decay of ${}^{85}$Ga. Advanced shell-model calculations were used to analyze experimental data on ${}^{85}$Ge and ${}^{84}$Ge.

Beta decay of $^{86}\mathrm{Ga}$ was studied by means of $\ensuremath{\beta}$-neutron-$\ensuremath{\gamma}$ spectroscopy. An isotopically pure $^{86}\mathrm{Ga}$ beam was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and high-resolution electromagnetic separation. The decay of $^{86}\mathrm{Ga}$ revealed a half-life of ${43}_{\ensuremath{-}15}^{+21}\text{ }\text{ }\mathrm{ms}$ and large $\ensuremath{\beta}$-delayed one-neutron and two-neutron branching ratios of ${P}_{1n}=60(10)%$ and ${P}_{2n}=20(10)%$. The $\ensuremath{\beta}\ensuremath{\gamma}$ decay of $^{86}\mathrm{Ga}$ populated a 527 keV transition that is interpreted as the deexcitation of the first ${2}^{+}$ state in the $N=54$ isotone $^{86}\mathrm{Ge}$ and suggests a quick onset of deformation in Ge isotopes beyond $N=50$.

Short lived neutron rich nuclei including 93 Br, 93 Kr and 94 Kr were produced in proton induced fission of 238 U at the HRIBF in Oak Ridge. Their beta decay was studied by means of a high resolution on line mass separator and beta gamma spectroscopy methods. The half life of 93Br T1/2 = 152(8) ms and delayed branching ratio of Pn = 53-8+11 may be compared to the previously reported values of T1/2 = 102(10) ms and Pn = 68(7)%. At the same time the half life of 94Kr T1/2 = 227(14) ms and B delayed branching ratio of Pn = 1.9+0.6 0.2 % of 93Kr are in very good agreement with literature values. The decay properties of 93Br include four new gamma transitions following beta delayed neutron emission.

The $\ensuremath{\beta}$-decay properties of several neutron-rich germanium and arsenic isotopes were measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The measurements of almost-pure radioactive sources were enabled by the combination of ion-source chemistry and two-stage mass separation. The half-life of ${}^{86}$Ge ($226\ifmmode\pm\else\textpm\fi{}21$ ms) was determined for the first time, while those of ${}^{84,85}$Ge and ${}^{84\ensuremath{-}87}$As were remeasured. The results are compared to theoretical predictions of the gross theory of $\ensuremath{\beta}$ decay, the finite-range droplet model, and the new calculations using the energy density functional DF3a with continuum quasiparticle random-phase approximation (CQRPA). We confirm the robustness and good predictive power of the latter model for nuclei near closed shells. These DF3a+CQRPA calculations were used recently to analyze $r$-process isobaric abundances.

The {beta} decays of neutron-rich nuclei near the doubly magic {sup 78}Ni were studied at the Holifield Radioactive Ion Beam Facility using an electromagnetic isobar separator. The half-lives of {sup 82}Zn (228 {+-} 10 ms), {sup 83}Zn (117 {+-} 20 ms), and {sup 85}Ga (93 {+-} 7 ms) were determined for the first time. These half-lives were found to be very different from the predictions of the global model used in astrophysical simulations. A new calculation was developed using the density functional model, which properly reproduced the new experimental values. The robustness of the new model in the {sup 78}Ni region allowed us to extrapolate data for more neutron-rich isotopes. The revised analysis of the rapid neutron capture process in low entropy environments with our new set of measured and calculated half-lives shows a significant redistribution of predicted isobaric abundances strengthening the yield of A > 140 nuclei.

The$\ensuremath{\beta}$-decay properties of neutron-rich Cu isotopes produced in proton-induced fission of ${}^{238}$U were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The data were collected using high-resolution online mass separation, reacceleration, and digital $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\gamma}$ spectroscopy methods. An improved decay scheme of $N=49$ ${}^{78}$Cu and the first observation of $N=50$ ${}^{79}$Cu $\ensuremath{\beta}$-delayed neutron decay followed by a gamma transition are reported. Spin and parity (5${}^{\ensuremath{-}}$) are deduced for ${}^{78gs}$Cu. The $\ensuremath{\beta}$-delayed neutron branching ratios (${P}_{\ensuremath{\beta}n}$) for the ${}^{77}$Cu and ${}^{79}$Cu precursors are analyzed with the help of nuclear structure models.

A. Pakou1, N. Patronis1, D. Pierroutsakou2, A.M. Sanchez-Benitez3, L. Acosta3,4, N. Alamanos5, A. Boiano2, G. Inglima6, D. Filipescu7, T. Glodariu7, A. Guglielmetti8, M. La Commara6, G. Lalazissis9, I. Martel3, C. Mazzocchi8, M. Mazzocco10, P. Molini10, C. Parascandolo2, M. Sandoli6, C. Signorini10, R. Silvestri6, F. Soramel10, M. Romoli2, E. Stiliaris11, A. Trzcinska12, K. Zerva1, E. Vardaci6, A. Vitturi10.

Fission fragments from neutron-induced fission of ${}^{235}$U produced at the high-flux reactor of the Institut Laue-Langevin, Grenoble, were separated with the Lohengrin separator to provide a beam of neutron-rich ${}^{85}\phantom{\rule{-0.16em}{0ex}}$As nuclei. The ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of ${}^{85}\phantom{\rule{-0.16em}{0ex}}$As to ${}^{85}$Se was studied using $\ensuremath{\gamma}$-$\ensuremath{\gamma}$ and $\ensuremath{\beta}$-$\ensuremath{\gamma}$ coincidence techniques. ${}^{85}$Se was also studied using the prompt-$\ensuremath{\gamma}$ coincidence data from spontaneous fission of ${}^{248}$Cm and ${}^{252}$Cf measured with the Eurogam2 and Gammasphere Ge arrays, respectively. The combination of $\ensuremath{\beta}$ decay and prompt-$\ensuremath{\gamma}$ data enabled the determination of spins and parities of low-energy excited states in ${}^{85}$Se. There are new arguments supporting the $5/{2}^{\ensuremath{-}}$ assignment for the ground state of ${}^{85}\phantom{\rule{-0.16em}{0ex}}$As.

An experiment to search for the $\ensuremath{\alpha}$ decay of ${}^{112}$Cs has been performed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. The $\ensuremath{\alpha}$ decay of ${}^{112}$Cs was not observed, thus setting the upper limit of the $\ensuremath{\alpha}$ branching ratio at 0.26$%$. The half-life of ${}^{112}$Cs was measured as $506\ifmmode\pm\else\textpm\fi{}55\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}$s. In the same measurement the decay properties of its proton decay daughter ${}^{111}$Xe were also reinvestigated. The newly measured $\ensuremath{\alpha}$ branching ratio for ${}^{111}$Xe is $10.4\ifmmode\pm\else\textpm\fi{}1.9\phantom{\rule{0.16em}{0ex}}%$. The experimental proton separation energies ${S}_{p}$ for odd-$Z$ nuclei above ${}^{100}$Sn were compared to shell model calculations. The calculated proton separation energies for ${}^{103}$Sb and ${}^{102}$Sb point to half-lives of the order of 10 ps and 1 ns, respectively.

The decay of the extremely neutron-deficient $^{48}\mathrm{Ni}$ was studied by means of an imaging time-projection chamber, which allowed the recording of tracks of charged particles. The decays of six atoms were observed. Four of them clearly correspond to two-proton radioactivity, providing the first direct evidence for this decay mode in $^{48}\mathrm{Ni}$. Two decays represent $\ensuremath{\beta}$-delayed proton emission. The half-life of $^{48}\mathrm{Ni}$ is determined to be ${T}_{1/2}=2.{1}_{\ensuremath{-}0.4}^{+1.4}$ ms.

The rate of the carbon-nitrogen-oxygen (CNO) cycle of hydrogen burning is controlled by the {sup 14}N(p,{gamma}){sup 15}O reaction. The reaction proceeds by capture to the ground states and several excited states in {sup 15}O. In order to obtain a reliable extrapolation of the excitation curve to astrophysical energy, fits in the R-matrix framework are needed. In an energy range that sensitively tests such fits, new cross-section data are reported here for the four major transitions in the {sup 14}N(p,{gamma}){sup 15}O reaction. The experiment has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) 400-kV accelerator placed deep underground in the Gran Sasso facility in Italy. Using a composite germanium detector, summing corrections have been considerably reduced with respect to previous studies. The cross sections for capture to the ground state and to the 5181, 6172, and 6792 keV excited states in {sup 15}O have been determined at 359, 380, and 399 keV beam energy. In addition, the branching ratios for the decay of the 278-keV resonance have been remeasured.

The $\ensuremath{\beta}$ decay of $^{75}\mathrm{Cu}$ [${t}_{1/2}=1.222(8)$s] to levels in $^{75}\mathrm{Zn}$ was studied at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory. The $\ensuremath{\gamma}\ensuremath{\gamma}$ and $\ensuremath{\beta}\ensuremath{\gamma}$ data were collected at the Low-energy Radioactive Ion Beam Spectroscopy Station using the high-resolution isobar separator to obtain a purified $^{75}\mathrm{Cu}$ beam with a rate of over 2000 ions per second. The excited states in $^{75}\mathrm{Zn}$ have been identified for the first time. A total of 120 $\ensuremath{\gamma}$-ray transitions were placed in a level scheme containing 59 levels including two states above the neutron separation energy and a previously unknown $1/{2}^{\ensuremath{-}}$ isomeric state at 127 keV. Spins and parities of several states were deduced and interpreted based on the observed $\ensuremath{\beta}$ feeding and $\ensuremath{\gamma}$-decay pattern.

The $\ensuremath{\beta}$ decay of the $N=51$ nucleus $^{81}\mathrm{Zn}$ was studied by means of $\ensuremath{\beta}$-$\ensuremath{\gamma}$ spectroscopy and from isotopically pure beams produced at the Holifield Radioactive Ion Beam Facility (HRIBF). We observe several competing $\ensuremath{\beta}$ transitions populating $^{81}\mathrm{Ga}$ that are interpreted as allowed Gamow-Teller decays to positive parity, core excited states, and first-forbidden decays to negative parity states. The measured $\ensuremath{\beta}$-decay pattern suggests an assignment of ${I}^{\ensuremath{\pi}}=5/{2}^{+}$ for the $^{81}\mathrm{Zn}$ ground state. The systematics of core excited states in $N=50$ isotones indicate a strengthening of the $N=40$ subshell gap near $^{78}\mathrm{Ni}$.

The {sup 15}N(p,{gamma}){sup 16}O reaction represents a breakout reaction linking the first and second cycles of the CNO cycles redistributing the carbon and nitrogen abundances into the oxygen range. The reaction is dominated by two broad resonances, at E{sub p}=338 and 1028 keV, and a direct capture contribution to the ground state of {sup 16}O. Interference effects between these contributions both in the low-energy region (E{sub p}

Charged reaction products originated from the interaction of the loosely bound radioactive ion beam {sup 17}F (S{sub p}=600 keV) with the proton-shell closed {sup 58}Ni target were measured at two colliding energies slightly above the Coulomb barrier. The collected data were analyzed within the framework of the optical model to deduce the reaction cross section and to investigate the role played by inelastic excitations, transfer channels, and the breakup process {sup 17}F{yields}{sup 16}O+p at near-barrier energies. The reaction cross section at the lower {sup 17}F energy showed a moderate enhancement ({approx}20%) with respect to that of the system {sup 16}O+{sup 58}Ni. At this energy direct reaction channels were also found to be more relevant than those for the reaction induced from the tightly bound projectile {sup 16}O on the same target. Both features could be strongly related to the very low binding energy of the {sup 17}F valence proton.

Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar $H$-shell burning. In particular, the strengths of low-energy resonances with $El200$ keV in $^{25}\mathrm{Mg}$($p,\ensuremath{\gamma}$)$^{26}\mathrm{Al}$ determine the production of $^{26}\mathrm{Al}$ and a precise knowledge of these nuclear data is highly desirable. Absolute measurements at such low energies are often very difficult and hampered by $\ensuremath{\gamma}$-ray background as well as changing target stoichiometry during the measurements. The latter problem can be partly avoided using higher-energy resonances of the same reaction as a normalization reference. Hence the parameters of suitable resonances have to be studied with adequate precision. In the present work we report on new measurements of the resonance strengths $\ensuremath{\omega}\ensuremath{\gamma}$ of the $E=214$, $304$, and $326$ keV resonances in the reactions $^{24}\mathrm{Mg}$($p,\ensuremath{\gamma}$)$^{25}\mathrm{Al}$, $^{25}\mathrm{Mg}$($p,\ensuremath{\gamma}$)$^{26}\mathrm{Al}$, and $^{26}\mathrm{Mg}$($p,\ensuremath{\gamma}$)$^{27}\mathrm{Al}$, respectively. These studies were performed at the LUNA facility in the Gran Sasso underground laboratory using multiple experimental techniques and provided results with a higher accuracy than previously achieved.

The structure of neutron-rich nuclei beyond $^{78}\mathrm{Ni}$ was studied using postaccelerated radioactive beams of $^{83,84,85}\mathrm{Ga}$ utilizing $\ensuremath{\beta} \ensuremath{\gamma}$ and $\ensuremath{\beta}\ensuremath{-}n \ensuremath{\gamma}$ spectroscopy. Our data, when combined with energy level systematics, suggests a possible new spherical subshell closure at $N=58$ is created by the nearly degenerated $\ensuremath{\nu}3{s}_{1/2}$ and $\ensuremath{\nu}2{d}_{5/2}$ orbitals being well separated from other orbitals above $N=50$. The near degeneracy of these states could be evidenced by isomerism in this region. The energies of the ${2}_{1}^{+}$ and proposed ${4}_{1}^{+}$ states observed in $N=52$ $^{84}\mathrm{Ge}$ are interpreted as an indication of a possible weakening of the doubly magic $^{78}\mathrm{Ni}$ core for nuclei beyond $N=50$. The experimental evidence is supported by spherical HFB calculations using the ${\mathrm{SkO}}_{T}$ functional involving the tensor term in the nucleon-nucleon interaction.

Isobarically purified beams of {sup 77}Cu with energies of 225 and 0.2 MeV were used at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory to study {beta} decay into states in {sup 77}Zn. Data taken at 225 MeV allowed the determination of absolute branching ratios relative to the decay of {sup 77}Cu for this {beta} decay as well as its daughters. From these we obtained a refined {beta}-delayed neutron emission probability of 30.3(22)% and a probability that the decay proceeds through {sup 77}Zn{sup g} of 49.1(26)%. A total of 64 {gamma} rays were placed in a level scheme for {sup 77}Zn containing 35 excited states including one state above the neutron separation energy, whereas two {gamma} rays were observed for the {beta}n branch to states in {sup 76}Zn. The growth and decay curves of some prominent {gamma} rays indicate a single {beta}-decaying state with a half-life of 480(9) ms. The decay pattern for {sup 77}Cu, with observed feeding of 8(3)% to 7/2{sup +} {sup 77}Zn{sup g} and 6(3)% to 1/2{sup -} {sup 77}Zn{sup m}, in contrast to the large feeding observed for decay of {pi}p{sub 3/2} {sup 73}Cu{sup g} to 1/2{sup -} {sup 73}Zn{sup g}, strongly suggestsmore » a {pi}f{sub 5/2} ground state for the studied {sup 77}Cu activity.« less

The $\ensuremath{\beta}$-delayed neutron branching ratios (${P}_{\ensuremath{\beta}n}$) for nuclei near doubly magic $^{78}\mathrm{Ni}$ have been directly measured using a new method combining high-resolution mass separation, reacceleration, and digital $\ensuremath{\beta}\mathrm{\text{\ensuremath{-}}}\ensuremath{\gamma}$ spectroscopy of $^{238}\mathrm{U}$ fission products. The ${P}_{\ensuremath{\beta}n}$ values for the very neutron-rich isotopes $^{76--78}\mathrm{Cu}$ and $^{83}\mathrm{Ga}$ were found to be much higher than previously reported and predicted. Revised calculations of the $\ensuremath{\beta}n$ process, accounting for new mass measurements and an inversion of the $\ensuremath{\pi}2{p}_{3/2}$ and $\ensuremath{\pi}1{f}_{5/2}$ orbitals, are in better agreement with these new experimental results.