The neutron long counter NERO for studies of β-delayed neutron emission in the r-process

Abstract The neutron long counter NERO was built at the National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, for measuring β -delayed neutron-emission probabilities. The detector was designed to work in conjunction with a β -delay implantation station, so that β decays and β -delayed neutrons emitted from implanted nuclei can be measured simultaneously. The high efficiency of about 40%, for the range of energies of interest, along with the small background, are crucial for measuring β -delayed neutron emission branchings for neutron-rich r-process nuclei produced as low intensity fragmentation beams in in-flight separator facilities.