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Partial cross sections of the 89Y(p, γ )90Zr reaction have been measured to investigate the γ-ray strength function in the neutron–magic nucleus 90Zr. For five proton energies between E p = 3.65 MeV and E p = 4.70 MeV partial cross sections for the population of seven discrete states in 90Zr have been determined by means of in-beam γ-ray spectroscopy. Since these γ-ray transitions are dominantly of E1 character, the present measurement allows an access to the low-lying dipole strength in 90Zr. A γ-ray strength function based on the experimental data could be extracted, which is used to describe the total and partial cross sections of this reaction by Hauser–Feshbach calculations successfully. Significant differences with respect to previously measured strength functions from photoabsorption data point towards deviations from the Brink–Axel hypothesis relating the photo-excitation and de-excitation strength functions.
NeuLAND (New Large-Area Neutron Detector) is the next-generation neutron detector for the R3B (Reactions with Relativistic Radioactive Beams) experiment at FAIR (Facility for Antiproton and Ion Research). NeuLAND detects neutrons with energies from 100 to 1000 MeV, featuring a high detection efficiency, a high spatial and time resolution, and a large multi-neutron reconstruction efficiency. This is achieved by a highly granular design of organic scintillators: 3000 individual submodules with a size of 5 × 5 × 250 cm3 are arranged in 30 double planes with 100 submodules each, providing an active area of 250 × 250 cm2 and a total depth of 3 m. The spatial resolution due to the granularity together with a time resolution of 150 ps ensures high-resolution capabilities. In conjunction with calorimetric properties, a multi-neutron reconstruction efficiency of 50% to 70% for four-neutron events will be achieved, depending on both the emission scenario and the boundary conditions allowed for the reconstruction method. We present in this paper the final design of the detector as well as results from test measurements and simulations on which this design is based.