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An overview of the main directions of present-day studies with quasimonochromatic γ beams are discussed with an emphasis on the research opportunities which will be offered at the Extreme Light Infrastructure Nuclear Physics (ELI-NP) facility at Magurele near Bucharest in Romania. Experiments with γ beams at the extremes of high temperature and high neutron-to-proton ratios are outlined. Some of the experimental setups for nuclear structure, reaction and astrophysics studies, which are available at ELI-NP, are described. Perspectives for studies of exotic nuclei within the Gamma Factory experiment at CERN are discussed. The expected fission-fragment yields at the Gamma Factory are presented. The perspectives for nuclear structure studies with γ rays with orbital angular momentum are outlined. [ABSTRACT FROM AUTHOR]

The use of multi-nucleon transfer (MNT) reactions to produce neutronrich nuclei in the heavy region has received an increased attention in the last decade. The feasibility of employing such reactions at the FRS Ion Catcher facility at GSI and the IGISOL facility at JYFL is studied using a combination of theoretical calculations and experiment simulations. The reactions are computed within a Langevin-type model, and the Geant program is used to simulate the transport of the resulting products within the experimental setups of the above-mentioned facilities. The angular distribution of ion release, possible target choices and target-to-beam-dump distances are discussed. [ABSTRACT FROM AUTHOR]

Simulations providing estimates of the ELI-NP gamma-beam energy bandwidths and beam spot dimensions for the collimated beams, and expected fission rates with the narrow-width beams of bandwidth 0.3% and 0.5% on actinide targets, 238U and 232Th, are reported. These estimates support the feasibility of precise transmission resonance measurements with the narrow-width ELI-NP γ beams. The status of the design and construction of a state-of-the-art experimental array, consisting of four double-sided, Frisch-gridded Bragg ionization chambers, coupled to ΔE-E detectors, is reported. [ABSTRACT FROM AUTHOR]

The mission of the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility is to use extreme electromagnetic fields for nuclear physics research. At ELI-NP, high-power lasers together with a very brilliant γ-ray beam are the main research tools. Their targeted operational parameters are described. The emerging experimental program of the facility in the field of nuclear physics is reported and the main directions of the research envisioned are presented. The experimental instrumentation, which will operate at ELI-NP for the realization of the research program, is discussed. The expected impact of ELI-NP on the future advance of the field is summarized. [ABSTRACT FROM AUTHOR]

The neutron-rich isotopes of cadmium up to the N=82 shell closure have been investigated by high-resolution laser spectroscopy. Deep-uv excitation at 214.5 nm and radioactive-beam bunching provided the required experimental sensitivity. Long-lived isomers are observed in 127Cd and 129Cd for the first time. One essential feature of the spherical shell model is unambiguously confirmed by a linear increase of the 11/2- quadrupole moments. Remarkably, this mechanism is found to act well beyond the h11/2 shell. [ABSTRACT FROM AUTHOR]

Excited states in 129I were populated with the 124Sn(7Li,2n) reaction at 23 MeV. In-beam measurements of γ-ray coincidences were performed with an array of eight HPGe detectors and five LaBr3(Ce) scintillation detectors. Based on the γγ coincidence data, a positive parity band structure built on the 7/2+ ground state was established and the nπg7/2 configuration at oblate deformation was assigned to it. The results are compared to interacting Boson-Fermion model (IBFM) and total Routhian surface (TRS) calculations. [ABSTRACT FROM AUTHOR]

Background: Nuclei in the A " 190 mass region show gradual shape changes from prolate through nonaxial deformed shapes and ultimately towards spherical shapes as the Pb region is approached. Exploring how this shape evolution occurs will help us understand the evolution of collectivity in this region. Purpose: The level scheme of the 192 Au nucleus in A "190 region was studied in order to deduce its deformations. Methods: High-spin states of 192Au have been populated in the 186W("B, 5n) reaction at a beam energy of 68 MeV and their ? decay was studied using the YRAST Ball detector array at the Wright Nuclear Structure Laboratory (WNSL), Yale University. Results: Based on double and triple ?-ray coincidence data the level scheme of 192 Au has been extended up to Ip = 32+ at an excitation energy of ~6 MeV. Conclusion: The results are discussed in the framework of pairing and deformation self-consistent total Routhian surface (TRS) and cranked shell model (CSM) calculations. The comparison of the experimental observations with the calculations indicates that this nucleus takes a nonaxial shape similar to other Au nuclei in this region. [ABSTRACT FROM AUTHOR]

The spectroscopic quadrupole moment of the T1/2=9.4(5) ns isomer in 193Pb at an excitation energy Eex=(2585+x) keV is measured by the time-differential perturbed angular distribution method as ∣Qx∣=2.6(3) e b. Spin and parity Iπ=27/2¯ are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the 1i13/2 subshell with the (3s1/2-21h9/21i13/2)11- proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation ϵ2=-0.11, similar to that of the 11¯proton intruder states, which nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head. [ABSTRACT FROM AUTHOR]

High level of electromagnetic radiation is produced in the interaction of relativistic ions with matter. A model to simulate it within GEANT4 has been developed in order to evaluate these sources of background and their influence on the experimental spectra. New classes have been added to the standard GEANT4 program libraries, describing the radiative electron capture, primary bremsstrahlung and secondary bremsstrahlung processes. Simulations of experiments within the RISING stopped beam campaign and comparison with the experimental results are presented. [ABSTRACT FROM AUTHOR]

Lifetimes of excited states in 128Ce were measured using the recoil distance Doppler-shift (RDDS) and the Doppler-shift attenuation (DSAM) methods. The experiments were performed at the Wright Nuclear Structure Laboratory of Yale University. Excited states of 128Ce were populated in the 100Mo(32Si,4n) reaction at 120 MeV and the nuclear γ decay was measured with an array of eight Clover detectors positioned at forward and backward angles. The deduced yrast transition strengths together with the energies of the levels within the ground-state (gs) band of 128Ce are in agreement with the predicted values for the X(5) critical point symmetry. Thus, we suggest 128Ce as a benchmark X(5) nucleus in the mass A ≈ 130 region. [ABSTRACT FROM AUTHOR]

The measured spectroscopic quadrupole moments and deduced deformations of the 194,196Pb(11-) intruder isomers are reevaluated, making use of the recently measured magnetic moments of these states. This adjustment is necessary since the quadrupole moments were obtained from Level Mixing Spectroscopy measurements, being sensitive to the ratio of the quadrupole interaction frequency and the magnetic moment. The results confirm the moderate deformation of the states. A systematic comparison between the updated experimental and the available theoretical values is presented. [ABSTRACT FROM AUTHOR]

We report results from a pioneering experiment to measure the g factors of isomeric states of neutron-rich nuclei around [sup 68]Ni, far from the valley of β stability. For the first time, the timedependent perturbed angular distribution method was applied in combination with the heavy-ion-γ correlation technique to study g factors of spin-aligned isomers produced in a projectile fragmentation reaction and mass-separated. Some technical aspects are discussed and illustrated with preliminary results. [ABSTRACT FROM AUTHOR]

Magnetic moment measurements of isomeric states in neutron-rich isotopes populated in photofission using γ-beam facility at the Extreme Light Infrastructure−Nuclear Physics (ELI-NP) laboratory aim at addressing many open questions related to the structure of the nuclei in A around 100 and 130 mass regions. The possibility of such measurements at ELI-NP is briefly discussed here using Geant4 Monte Carlo simulations. The present paper report the estimates of γ-beam profile at the target, fission fragment production rates and the possible target geometry. [ABSTRACT FROM AUTHOR]

The neutron-deficient cadmium isotopes have been measured by high-resolution laser spectroscopy at CERN-ISOLDE. The electromagnetic moments of 101Cd have been determined for the first time and the quadrupole-moment precision of 103Cd has been vastly improved. The results on the sequence of 5/2+ ground states in 101-109Cd are tentatively discussed in the context of simple structure in complex nuclei as similarities are found with the 11/2- states in the neutron-rich cases. Comparison with shell-model calculations reveals a prominent role of the two holes in the Z=50 core. [ABSTRACT FROM AUTHOR]

An empirical parametrization for the production cross sections of 238U photofission fragments at low energies (Eγ<30 MeV) is developed. This parametrization, GIF238U, consists of three parts, namely, the photofission cross section, the mass yield, and the isobaric charge distribution. The photofission cross section is parametrized to reproduce measured data over a wide energy range. The mass yield distribution is described by the energy-dependent multimodal fission model. The isobaric charge distribution is improved, relative to other parametrizations, to describe many experimental data sets over a broad mass range. Comparisons with different measured 238U photofission data sets at various energies reveal that GIF238U is in very good agreement with measured elemental and mass yields and can accurately reproduce experimental isotopic yields. Production cross sections (yields) of photofission fragments calculated by this parametrization indicate that many neutron-rich nuclei approaching the r-process path can be accessed via photofission of 238U at radioactive-beam facilities. [ABSTRACT FROM AUTHOR]

The quadrupole interaction of high-spin isomers in 193Pb implanted into solid Hg cooled at a temperature T = 170 K has been investigated by the time-differential perturbed γ-ray angular-distribution method. Spectroscopic quadrupole moment values of &verbar;Qs&verbar; = 0.22(2) eb and 0.45(4) eb have been deduced for the 21/2- and 33/2+ three-neutron states, respectively. A much higher value &verbar;Qs&verbar; = 2.84(26) eb has been determined for the 29/2- isomer, the band head of a magnetic rotational band. [ABSTRACT FROM AUTHOR]

Isomer shifts have been determined in 111-129Cd by high-resolution laser spectroscopy at CERN-ISOLDE. The corresponding mean square charge-radii changes, from the 1/2+ and the 3/2+ ground states to the 11/2- isomers, have been found to follow a distinct parabolic dependence as a function of the atomic mass number. Since the isomers have been previously associated with simplicity due to the linear mass dependence of their quadrupole moments, the regularity of the isomer shifts suggests a higher order of symmetry affecting the ground states in addition. A comprehensive description assuming nuclear deformation is found to accurately reproduce the radii differences in conjunction with the known quadrupole moments. This intuitive interpretation is supported by covariant density functional theory. [ABSTRACT FROM AUTHOR]

Post-accelerated isomerically purified radioactive beams, available at the CERN On-Line Isotope Mass Separator facility using the resonant ionization laser technique, have been used to study the Coulomb excitation of the I&pi; = 3- state in 70Cu (Z = 29, N = 41). While first results using a Iπ =6- beam were reported previously, the present complementary experiment allows us to complete the study of the multiplet of states (3-, 4- ,5-,6-) arising from the π2p3νlg9/2 configuration. Besides the known γ-ray transition deexciting the 4- state, a ground-state γ ray of 511(3) keV was observed for the first time and was unambiguously associated with the 5- state deexcitation. This observation fixes the energy, spin, and parity of this state, completing the low-energy level scheme of 70Cu. B(E2) values for all possible E2 transitions within the multiplet were determined. A comparison with large-scale shell model calculations using different interactions and valence spaces shows the importance of proton excitation across the Z = 28 shell gap and the role of the 2d5/2 neutron orbital. [ABSTRACT FROM AUTHOR]

We report a measurement of the g-factor of the I π = 9/2+, t 1/2 = 22ns isomer in 65Ni. The state of interest was populated and spin-oriented using a single-neutron transfer on an enriched 64Ni target. The value, which was obtained, g(9/2+,65m Ni) = - 0.296(3) is well in agreement with the g-factors of the other 9/2+ states in the region and with large-basis shell model calculations. The known g-factor of the 9/2+ isomer in 63Ni was used in order to verify the strength of the hyperfine field of Ni( Ni) at room temperature. [ABSTRACT FROM AUTHOR]

Lifetimes of exited states in 134Pr were measured be means of the recoil distance Doppler-shift and Doppler-shift attenuation techniques. The experiments were performed at IReS, Strasbourg using the EUROBALL IV spectrometer, in conjunction with the inner BGO ball and the Cologne coincidence plunger apparatus. Exited states in 134Pr were populated in the fusion-evaporation reaction 119Sn(19F, 4n)134Pr. Reduced transition probabilities in 134Pr are compared to the predictions of the two quasiparticle+triaxial rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in 134Pr underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in 134Pr can be supported. [ABSTRACT FROM AUTHOR]

We report on the first use of post-accelerated radioactive isomeric beams. Long-lived isomeric states in 68Cu and 70Cu have been produced and separated at ISOLDE, CERN. Subsequently they were post-accelerated to 2.86 MeV/u and sent to a target in the center of the MINIBALL spectrometer, used for the detection of the γ-rays of interest. The preliminary results from the Coulomb excitation of the Iπ=6-, 1+ states in 68Cu and the Iπ=6- one in 70Cu, compared to a large-scale shell model calculations, hint the importance of the excitations across the Z=28 gap for the understanding of the nuclear structure in the neutron-rich N=40 region. [ABSTRACT FROM AUTHOR]

Nuclear mass is a key property of atomic nuclei. The accurate determination of nuclear masses provides information for the nuclear shell structure and nuclear deformations. The FRS Ion Catcher experimental setup at GSI, Darmstadt was used to perform mass measurements of 252Cf fragments using a multiple-reflection time-of-flight mass spectrometer. The reported results are compared to previous measurements and their implication in the estimation of two-neutron separation energy is discussed. [ABSTRACT FROM AUTHOR]

Differences in mean-square nuclear charge radii of 100-130Cd are extracted from high-resolution collinear laser spectroscopy of the 5s ²S1/2→5p ²P3/2 transition of the ion and from the 5s5p ³P2→5s6s ³S1 transition in atomic Cd. The radii show a smooth parabolic behavior on top of a linear trend and a regular odd-even staggering across the almost complete sdgh shell. They serve as a first test for a recently established new Fayans functional and show a remarkably good agreement in the trend as well as in the total nuclear charge radius. [ABSTRACT FROM AUTHOR]

Excited states of the neutron-rich nuclei 97,99Rb were populated for the first time using the multistep Coulomb excitation of radioactive beams. Comparisons of the results with particle-rotor model calculations provide clear identification for the ground-state rotational band of 97Rb as being built on the pg9/2 [431] 3/2+ Nilsson-model configuration. The ground-state excitation spectra of the Rb isotopes show a marked distinction between single-particle-like structures below N=60 and rotational bands above. The present study defines the limits of the deformed region around A~100 and indicates that the deformation of 97Rb is essentially the same as that observed well inside the deformed region. It further highlights the power of the Coulomb-excitation technique for obtaining spectroscopic information far from stability. The 99Rb case demonstrates the challenges of studies with very short-lived postaccelerated radioactive beams. [ABSTRACT FROM AUTHOR]

A precise measurement of the g factor of the first-excited state in the self-conjugate (N=Z) nucleus 24Mg is performed by a new time-differential recoil-in-vacuum method based on the hyperfine field of hydrogenlike ions. Theory predicts that the g factors of such states, in which protons and neutrons occupy the same orbits, should depart from 0.5 by a few percent due to configuration mixing and meson-exchange effects. The experimental result, g=0.538±0.013, is in excellent agreement with recent shell-model calculations and shows a departure from 0.5 by almost 3 standard deviations, thus achieving, for the first time, the precision and accuracy needed to test theory. Proof of the new method opens the way for wide applications including measurements of the magnetism of excited states of exotic nuclei produced as radioactive beams. [ABSTRACT FROM AUTHOR]

We report on the spectroscopic quadrupole moment measurement of the 7/2¡" isomeric state in "JgS27 [E* = 320.5(5) keV, Tt/2 = 415(3) ns], using the time dependent perturbed angular distribution tech-nique at the RIKEN RIBF facility. Our value, | Qs |= 23(3)

The high-velocity transient-field (HVTF) technique was used to measure the g factor of the 2+ state of 72Zn produced as a radioactive beam. The transient-field strength was probed at high velocity in ferromagnetic iron and gadolinium hosts using 76Ge beams. The potential of the HVTF method is demonstrated and the difficulties that need to be overcome for a reliable use of the TF technique with high-Z, high-velocity radioactive beams are revealed. The polarization of K-shell vacancies at high velocity, which shows more than an order of magnitude difference between Z = 20 and Z = 30 is discussed. The g-factor measurement hints at the theoretically predicted transition in the structure of the Zn isotopes near N = 40. [ABSTRACT FROM AUTHOR]

The feasibility of measuring g -factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623keV $\ensuremath I^{\pi}=12^+$ isomer in 192Pb with $ \tau$ = 1.57 μs has been produced using the fragmentation of a 1 A GeV 238U beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)% of the maximum possible, is preserved during the separation process allowing the determination of magnetic moments. The measured values of the lifetime, $ \tau$ = 1.54(9) μs, and the g -factor, g = - 0.175(20) , agree with the results of previous investigations using fusion-evaporation reactions. [ABSTRACT FROM AUTHOR]

Information on the first excited states in the N = Z = 41 nucleus 82Nb sheds light on the competition of isospin T = 0 and T = 1 states in the A ∼ 80 region. The measurement was performed at the GSI laboratory using fragmentation of a 107Ag primary beam at 750 MeV/u on a 4 g/cm² 9Be target. The fragments were separated and identified unambiguously in the FRagment Separator. Three excited states were observed and the half-life estimate for the isomeric state was extracted. A tentative spin assignment based on the isobaric analogue states systematics in the Tz = 1 nucleus 82Zr, and transition probabilities indicate T = 1 character of the first two excited states, and T = 0 for the isomeric state. [ABSTRACT FROM AUTHOR]

The quadrupole interaction of the 11- and 12+ isomers in 192,194Pb nuclei has been investigated in the electric field gradient of metallic Bi polycrystalline lattice by the method of time-differential observation of the γ-rays perturbed angular distribution. The electric field gradient strength of the host Bi lattice has been calibrated by using as probe the 12+ isomer in 194Pb. The intrinsic quadrupole moments derived for the 11- isomers described by the π(1h9/21i13/2) intruder configuration are compared with the predictions of mean-field and interacting boson models. [ABSTRACT FROM AUTHOR]

The g-factor of the ground state of 31Al (T1/2=640 ms) has been measured by the β-NMR technique on a polarized secondary fragment beam at GANIL, Caen, France. The measured value of |g|=1.517(20) is compared with sd-shell model calculations, which allows the assignment of spin and parity Iπ=5/2+ to this state. The spectroscopy of neutron-rich Al isotopes on the border of the “island of inversion” is discussed in terms of the persistence of the N=20 shell closure for Z=13 nuclei. [Copyright &y& Elsevier]

First and preliminary results of an experiment aimed at measuring g-factors of isomeric states in neutron-rich nuclei in the vicinity of 68Ni are reported. Isomers near the predicted N=40 sub-shell closure in 69Cu, 67Ni and 66Co have been populated in the fragmentation of a 76Ge, 61.4 MeV/u beam onto a 145 mg/cm2 9Be target at GANIL. Here we report the results for the 357(2) ns, Iπ=13/2+ isomer in 69Cu for which a preliminary gyromagnetic ratio of |g|=0.195(9) was derived. The Larmor precession of the spin-oriented isomeric ensemble was measured by recording γ–ion correlations in a 20 μs time window. This pioneering experiment has indicated interesting nuclear structure information and shows promising possibilities for future studies of this kind. [Copyright &y& Elsevier]