The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-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 gamma 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 gamma-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. (C) 2011 Elsevier B.V. All rights reserved.AGATA and this work is supported by the European funding bodies and the EU Contract RII3-CT-2004-506065, the German BMBF under Grants 06K-167 and 06KY205I, the Swedish Research Council and the Knut and Alice Wallenberg Foundation, UK EPSRC Engineering and Physical Sciences Research Council, UK STFC Science and Technology Facilities Council, AWE plc, Scientific and Technological Research Council of Turkey (Proj. nr. 106T055) and Ankara University (BAP Proj. nr. 05B4240002), the Polish Ministry of Science and Higher Education under Grant DPN/N190/AGATA/2009, the Spanish MICINN under grants FPA2008-06419 and FPA2009-13377-C02-02, the Spanish Consolider-Ingenio 2010 Programme CPAN (contract number CSD2007-00042) the Generalitat Valenciana under Grant PROMETEO/2010/101, and research performed in the frame of the GSI-IN2P3 collaboration agreement number 02-42. MICINN, Spain, and INFN, Italy, through the AIC10-D-000568 bilateral action.Peer Reviewe

The neutron time-of-flight facility n_TOF features a white neutron source produced by spallation through 20GeV/ cprotons impinging on a lead target. The facility, aiming primarily at the measurement...

The energy-dependent cross section of the ${}^7\mathrm{Be}(n,\alpha ){}^4\mathrm{He}$ reaction, of interest for the so-called cosmological lithium problem in big bang nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of ${}^7\mathrm{Be}$ and by the low reaction cross section have been overcome at n_TOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the n_TOF facility at CERN, the availability of a sufficient amount of chemically pure ${}^7\mathrm{Be}$, and a specifically designed experimental setup. Coincidences between the two alpha particles have been recorded in two $\mathrm{Si}\text{−}{}^7\mathrm{Be}\text{−}\mathrm{Si}$ arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 1960s at a nuclear reactor. The energy dependence reported here clearly indicates the inadequacy of the cross section estimates currently used in BBN calculations. Although new measurements at higher neutron energy may still be needed, the n_TOF results hint at a minor role of this reaction in BBN, leaving the long-standing cosmological lithium problem unsolved.

At the neutron Lime-of-flight facility n_TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. \ud The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgroundsPostprint (author's final draft