Projectile-like fragment production studies: the role of magnetic rigidity*

At rare isotope beam facilities around the world, projectile fragmentation is used to create exotic beams. A primary beam strikes a production target, creating projectile-like fragments which are precursors to stable secondary beams used for experimentation. Due to the short-lived nature of these projectile-like fragments, it is impossible to directly observe them. The MoNA Collaboration designed and performed an experiment at the NSCL to study projectile-like fragment production. A 32Mg 86 MeV/u secondary beam struck a reaction target of 9Be, creating charged final fragments of sodium, neon and fluorine along with correlated neutrons. After the reaction target, charged fragments are bent by a Sweeper magnet into an ensemble of charged particle detectors, while neutrons continue into the Modular Neutron Array. The detection of charged final fragments is predicated on the magnetic acceptance range of the Sweeper magnet, which was varied to increase the number of observed isotopes. Analysis of neutron multiplicities in relation to fragment acceptance is necessary to accurately analyze these projectile-like fragments. Preliminary results of this study will be presented.