Neutron skin of Ni isotopes

Neutron skin can be deduced via simultaneous and independent measurement of the reaction cross sections and the charge changing cross sections. Ni isotopes, including doubly magic nucleus 78Ni, cover asymmetric parameter from 0 to 0.28. Thus the determination of the neutron skin in Ni isotopes may understand the nuclear equation of state via the density derivative coefficient, and thus the structure of the neutron star. Originally the measurements were planned at GSI, Germany. However the upgrade plan at GSI forced to shift the measurement at RIKEN, Japan. Thus the research & development of an Ion-chamber (IC, for the atomic-number identification) was newly required. As a result, new the IC with Z-resolution of 4-sigma separation is now completed. Now we are ready for the experiment.