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In recent decades, γ -ray spectroscopy has undergone a major technological leap forward, namely the technique of γ -ray tracking, and has attained a sensitivity that is two orders of magnitude larger than that provided by the former generation of Compton-shielded arrays. Indeed the gain is comparable with the achievements since the dawn of γ -ray spectroscopy. Such sensitivity can be further heightened by coupling γ -ray spectrometers to other detectors that record complementary reaction products such as light-charged particles for transfer reactions and scattered ions for Coulomb excitation measurements. Nucleon transfer reactions offer an excellent mean to probe the energies of shell model single-particle orbitals and to study migration in energy of these orbitals as we venture away from stability. Such measurements can also estimate the cross sections of processes relevant to stellar evolution and nucleosynthesis. The measurement of γ rays in coincidence with particles provides also information on the decay channel for unbound systems, which constitutes a useful input for astrophysics and nuclear structure near the drip-lines. Coulomb-excitation studies make it possible to infer collective structure in nuclei and to extract deformation properties of, in particular, open-shell systems. Here, selected examples will be presented, highlighting the power of these types of experiments when γ -ray observation is included. The development of the experimental methods is reviewed, showing the results achieved before the advent of γ -ray tracking. Examples of more recent experiments that have successfully exploited γ -ray tracking with AGATA are then presented as showcases for the outstanding performance of the composite detection systems. The outlook for experiments using newly developed devices such as GRIT and other detectors such as SPIDER is described. [ABSTRACT FROM AUTHOR]

The nuclear break-up of 6He on a 208Pb target was studied at 20A MeV using a secondary beam of 6He produced by the SPIRAL facility at GANIL. $ \alpha$ -particles were detected in coincidence with two neutrons with a large angular coverage and the reaction mechanism was identified. From the distribution of the relative angles between the two neutrons the correlation function was extracted. It shows a strong correlation at small relative angles attributed to the contribution of the di-neutron configuration of 6He . [ABSTRACT FROM AUTHOR]

Results from a study in inverse kinematics of the 24Ne(d, pγ)25Ne reaction, using a radioactive beam of 24Ne from the SPIRAL facility at GANIL, are reported. First, a brief overview is given of several methods using radioactive beams to study the classic single-nucleon transfer reactions such as (d, p) or (d, t)/(d, 3He), where the experimental design is strongly influenced by the extreme inverse kinematics. A promising approach to deliver good energy resolution is to combine a high geometrical efficiency for kinematically complete charged particle detection with a high efficiency array for gamma-ray detection. One of the first dedicated set-ups for this type of experiment is the TIARA silicon strip array combined with the EXOGAM segmented germanium array. Together they comprise a highly compact, position-sensitive particle array with 90% of 4π coverage, mounted inside a cubic arrangement of four segmented gamma-ray detectors in very close geometry with 67% of 4π active coverage. Using this setup, the structure of 25Ne has been studied via the (d, p) reaction. A pure ISOL beam of 105 s-1 of 24Ne at 10 MeV/ A was provided by SPIRAL and bombarded a CD2 target of 1 mg/cm2. The 25Ne was detected at the focal plane of the VAMOS spectrometer where the direct beam was separated and intercepted. Reaction protons were detected in coincidence with little background. Four resolved peaks were recorded between Ex = 0 and 4 MeV. The data confirm and extend the results from a multinucleon transfer study using the (13C,14O) reaction. Further information has been obtained using the energies of coincident gamma-rays. The reactions 24Ne(d, dγ)24Ne, 24Ne(d, t)23Ne and 24Ne(d, 3He)23F were recorded simultaneously and analysis of these is also underway. [ABSTRACT FROM AUTHOR]

Energy integrated reaction cross-section measurements of around sixty neutron-rich nuclei covering the region of closed shells N = 20 and N = 28 were performed at intermediate energy (30-65 A . MeV) using direct method. In this experiment, silicon detectors were used as active targets. The reduced strong absorption radii, r02, for 19 new nuclei (27F, 27,30Ne, 33Na, 28, 34-35Mg, 36-38Al, 38-40Si, 41-42P, 42-44S and 45Cl) are deduced for the first time. An additional 60 radii, also measured in this experiment, are compared to results from literature. A new quadratic parametrization is proposed for the nuclear radius as a function of the isospin in the region of closed shells N = 8 and N = 28. According to this parametrization, the skin effect is well reproduced and anomalous behaviour on the radii are observed in 23N, 29Ne, 33Na, 35Mg, 44S, 45Cl and 45Ar nuclei. [ABSTRACT FROM AUTHOR]

A new SPEG mass measurement experiment has been performed to determine masses closer to the neutron drip-line in the mass region A ∼ 10-50. The precision of 37 masses has been improved and 8 masses were measured for the first time. The region covered was motivated by the study of shell structure and of shape coexistence in the region of closed shells N = 20 and N = 28. The evolution of the two neutron separation energies and the shell correction energy have been studied as a function of the neutron number. The results thus obtained provide a means of identifying, in exotic nuclei, new nuclear structure effects that are well illustrated by the changes of the conventional magic structure. [ABSTRACT FROM AUTHOR]

Data have been obtained on exclusive single neutron knockout cross sections from 12Be to study its ground state structure. Preliminary cross sections for the first (0.32 MeV, $\ensuremath{^1\!/_2 ^-}$) and second (1.78 MeV, $\ensuremath{^5\!/_2 ^+}$, unbound) excited states in 11Be have been obtained, giving evidence of significant admixtures of both $\ensuremath{\nu(1p_{^1\!/_2})^2}$ and $\ensuremath{\nu(1d_{^5\!/_2})^2}$ configurations in the ground state of 12Be. [ABSTRACT FROM AUTHOR]

A measurement of the ( d, p) reaction in inverse kinematics at energies near the Coulomb barrier using a stable beam of 124Sn has been performed at ORNL’s Holifield Radioactive Ion Beam Facility (HRIBF). The sensitivity of proton angular distributions to the transferred angular momentum has been demonstrated. Spectroscopic factors have been extracted for three states and are in agreement with previous measurements made in normal kinematics. [ABSTRACT FROM AUTHOR]

The breakup ofMg intoO andBe fragments has been studied using the reactionsC(Mg,OBe)C andC(Ne,OBe)Be. In the latter case, discrete states are observed near 24-28 MeV of excitation inMg and the yield from this reaction is an order of magnitude greater than that of the former. This implies the excited configuration populated inMg is favoured by the transfer of an alpha-particle and would therefore suggest an association with a 4-particle 4-hole configuration. This suggests a link with the octupole stabilised deformed minimum which appears in Nilsson-Strutinsky calculations of the potential energy surface inMg, and also with the α -O - α structure predicted in cranked cluster model calculations. In the excitation spectrum no states appear above 31 MeV indicating a possible band termination in disagreement with recent results using theO+C reaction. These results are discussed in terms of the Harvey model. [ABSTRACT FROM AUTHOR]