One-nucleon removal reactions at the FRS

The fragment separator FRS at GSI was used as an energy-loss spectrometer to measure the longitudinal momentum distributions of 11,16,18C fragments after one-neutron removal, and these of 7,9Be after one-proton removal in a C target at relativistic energies. The one-nucleon removal cross-sections (σ−1n,σ−1p) were also measured and compared with existing results for stable neighboring nucleus. The width of the momentum distribution obtained for 18C and 7Be fragments was smaller compared with the same measured quantities for 12C and 8B. At the same time a significant increase in the cross-section of the one-proton removal channel (σ(19C)−1n and σ(8B)−1p) was observed. Those results, support a neutron halo structure in 19C, and the one-proton halo of 8B.