We have measured fragment cross-sections of projectile fragmentation reactions using primary beams of 40 Ca, 48 Ca, 58 Ni, and 64 Ni at 140 MeV/nucleon on 9 Be and 181 Ta targets. The cross-sections were obtained by integrating the momentum distributions of isotopes with Z 5 measured in the A1900 fragment separator. We compare the extracted cross-sections to the predictions of the empirical parametrization of fragmentation cross-sections (EPAX).

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We present an extensive overview of production cross sections and kinetic energies for the complete set of nuclides formed in the spallation of 136 Xe by protons at the incident energy of 1 GeV per nucleon. The measurement was performed in inverse kinematics at the GSI fragment separator. Slightly below the BusinaroGallone point, 136 Xe is the stable nuclide with the largest neutron excess. The kinematic data and cross sections collected in this work for the full nuclide production are a general benchmark for modeling the spallation process in a neutron-rich nuclear system, where fission is characterized by predominantly mass-asymmetric splits.

We report the first detailed study of the relative importance of the stripping and diffraction mechanisms involved in nucleon knockout reactions, by the use of a coincidence measurement of the residue and fast proton following one-proton knockout reactions. The measurements used the S800 spectrograph in combination with the HiRA detector array at the NSCL. Results for the reactions 9Be(9C,8B+X)Y and 9Be(8B,7Be+X)Y are presented and compared with theoretical predictions for the two reaction mechanisms calculated using the eikonal model. The data show a clear distinction between the stripping and diffraction mechanisms and the measured relative proportions are very well reproduced by the reaction theory. This agreement adds support to the results of knockout reaction analyses and their applications to the spectroscopy of rare isotopes.

The nuclide cross sections and the longitudinal velocity distributions of residues produced in the reactions of 136 Xe and 124 Xe at 1 A GeV in a lead target were measured at the highresolution magnetic spectrometer, the Fragment Separator (FRS) of GSI. The data cover a broad range of isotopes of the elements between Z = 3 and Z = 56 for 136 Xe and between Z = 5 and Z = 55 for 124 Xe, reaching down to cross sections of a few microbarns. The velocity distributions exhibit a Gaussian shape for masses above A = 20, while more complex behaviour is observed for lighter masses. The isotopic distributions for both reactions preserve a memory on the projectile N/Z ratio over the whole residue mass range.

International audienceThe N/Z dependence of projectile fragmentation at relativistic energies has been studied with the ALADIN forward spectrometer at the GSI Schwerionen Synchrotron (SIS). Stable and radioactive Sn and La beams with an incident energy of 600 MeV per nucleon have been used in order to explore a wide range of isotopic compositions. For the interpretation of the data, calculations with the statistical multifragmentation model for a properly chosen ensemble of excited sources were performed. The parameters of the ensemble, representing the variety of excited spectator nuclei expected in a participant-spectator scenario, are determined empirically by searching for an optimum reproduction of the measured fragment-charge distributions and correlations. An overall very good agreement is obtained. The possible modification of the liquid-drop parameters of the fragment description in the hot freeze-out environment is studied, and a significant reduction of the symmetry-term coefficient is found necessary to reproduce the mean neutron-to-proton ratios 〈N〉/Z and the isoscaling parameters of Z⩽10 fragments. The calculations are, furthermore, used to address open questions regarding the modification of the surface-term coefficient at freeze-out, the N/Z dependence of the nuclear caloric curve, and the isotopic evolution of the spectator system between its formation during the initial cascade stage of the reaction and its subsequent breakup

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In the present work we were able to synthesize and measure with high accuracy the production cross sections of more than 190 heavy neutron-rich nuclei by the in-flight fragmentation of relativistic 208 Pb projectiles, 26 of which were produced for the first time. This work has shown that the N = 126 region far below the doubly magic 208 Pb has become accessible experimentally and represents a step further towards the study of heavy neutron-rich nuclei approaching the r-process waiting point at A = 195.