The CERN n_TOF NEAR station for astrophysics- and application-related neutron activation measurements

Abstract

A new experimental area, the NEAR station, has recently been built at the CERN n_TOF facility, at a short distance from the spallation target (3 m). The new area, characterized by a neutron beam of very high flux, has been designed with the purpose of performing activation measurements of interest for astrophysics and various applications. The beam is transported from the spallation target to the NEAR station through a hole in the shielding wall of the target, inside which a collimator is inserted. The new area is complemented with a ɣ-ray spectroscopy laboratory, the GEAR station, equipped with a high-efficiency HPGe detector, for the measurement of the activity resulting from irradiation of a sample in the NEAR station. The use of a moderator/filter assembly is envisaged, in order to produce a neutron beam with quasi-Maxwellian energy distribution, of different thermal energies, necessary for the determination of Maxwellian Averaged Cross Sections of astrophysical interest. A new fast-cycling activation technique is also being investigated for measurements of reactions leading to isotopes of very short half life.