The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation γ-ray spectrometer. AGATA is based on the technique of γ-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a γ ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of γ-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector-response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer

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Time-resolved Schottky mass spectrometry has been applied to uranium projectile fragments which yielded the mass value for the 208 Hg (Z = 80, N = 128) isotope. The mass excess value of ME=-13265(31) keV has been obtained, which has been used to determine the proton-neutron interaction strength in 210 Pb, as a double difference of atomic masses. The results show a dramatic variation of the strength for lead isotopes when crossing the N=126 neutron shell closure, thus confirming the empirical predictions that this interaction strength is sensitive to the overlap of the wave-functions of the last valence neutrons and protons.Atomic nuclei are many-body systems in which the strong, weak and electromagnetic fundamental interactions play a major role by acting between the nucleons. The sum effect of these interactions is reflected in the total binding energy of the nucleus, which is directly connected with its mass [1]. Therefore, nuclear masses often provide hints to new nuclear structure effects. Indeed, shell structure and pairing correlations have been discovered through nuclear masses. Nuclear masses and binding energies are important, however, in a much wider domain. Examples occur in the studies of various nucleosynthesis processes in stars, in weak interaction physics relating to the unitarity of the CabibboKobayashi-Maskawa matrix, in tests of QED and in the determination of fundamental constants [2].Dedicated filters can be constructed from mass differences to isolate specific nucleonic interactions. One such filter is the average interaction strength of the last proton(s) with the last neutron(s) denoted δV pn . The proton-neutron interaction-being of fundamental interest for nuclear structure-has been intensively discussed in the last decades [3][4][5][6][7][8][9][10][11][12][13][14]. It has been shown that it is essential for the development of configuration mixing and for the onset of collectivity and deformation in nuclei [6], for changes of the underlying shell structure [7], and for the microscopic origins of phase transitional behavior in nuclei [7][8][9]. Being the largest along the N=Z line, the p−n interaction can be related to Wigner's SU(4) symmetry [3]. The average value of the p−n interaction strength can also be related to the nuclear symmetry energy [10]. Moreover, treatment of the nucleon-nucleon correlations finds similarities in interpreting other many-body systems: for example, odd-even staggering effects were observed in ultrasmall superconducting metallic grains [15]. This Letter will present a mass measurement for 208 Hg isotope, that provides one of the most important δV pn values in the entire nuclear chart.For even-even nuclei, the average p − n interaction of the last two protons with the last two neutrons can be defined as [13]:where B is the binding energy of the nucleus. By assuming that the nuclear core remains essentially unchanged, δV pn , by its definition, largely cancels the interactions of the last nucleons with the core. A given δV pn value for an even-even nucleus ref...

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