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Register a new userHeCTOr: the $^3$He Cryogenic Target of Orsay for direct nuclear reactions with radioactive beams
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Direct nuclear reactions with radioactive ion beams represent an extremely powerful tool to extend the study of fundamental nuclear properties far from stability. These measurements require pure and dense targets to cope with the low beam intensities. The $^3$He cryogenic target HeCTOr has been designed to perform direct nuclear reactions in inverse kinematics. The high density of $^3$He scattering centers, of the order of 10$^{20}$ atoms/cm$^2$, makes it particularly suited for experiments where low-intensity radioactive beams are involved. The target was employed in a first in-beam experiment, where it was coupled to state-of-the-art gamma-ray and particle detectors. It showed excellent stability in gas temperature and density over time. Relevant experimental quantities, such as total target thickness, energy resolution and gamma-ray absorption, were determined through dedicated Geant4 simulations and found to be in good agreement with experimental data.
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We discuss the possibility to build a neutron target for nuclear reaction studies in inverse kinematics utilizing a storage ring and radioactive ion beams. The proposed neutron target is a specially designed spallation target surrounded by a large moderator of heavy water (D$_2$O). We present the resulting neutron spectra and their properties as a target. We discuss possible realizations at different experimental facilities.
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To improve the ability of particle identification of the RIBLL2 separator at the HIRFL-CSR complex, a new high-performance detector for measuring fragment starting time and position at the F1 dispersive plane has been constructed and installed, and a method for achieving precise Br{ho} determination has been developed using the experimentally derived ion-optical transfer matrix elements from the measured position and ToF information. Using the high-performance detectors and the precise Br{ho} determination method, the fragments produced by the fragmentation of 78Kr at 300 MeV/nucleon were identified clearly at the RIBLL2-ETF under full momentum acceptance. The atomic number Z resolution of {sigma}Z~0.19 and the mass-to-charge ratio A/Q resolution of {sigma}A/Q~5.8e-3 were obtained for the 75As33+ fragment. This great improvement will increase the collection efficiency of exotic nuclei, extend the range of nuclei of interest from the A<40 mass region up to the A~80 mass region, and promote the development of radioactive nuclear beam experiments at the RIBLL2 separator.
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