Penning trap mass measurements of rare isotopes produced by projectile fragmentation with LEBIT at NSCL

The Low-Energy Beam and Ion Trap facility LEBIT at the NSCL at MSU has demonstrated that rare isotopes produced by fast-beam fragmentation can be slowed down and prepared for precision experiments with low-energy beams. High-pressure gas-stopping was combined with advanced ion manipulation techniques to carry out these studies with a high-precision 9.4-Tesla Penning trap mass spectrometer. The spectrometer has been used for a series of high precision mass measurements of short-lived neutron-and proton-rich isotopes during the past year. This paper presents an overview of the LEBIT facility and summarizes the first mass measurement results. The mass measurements of 81Se, where ground and isomeric states have been resolved, and of 80As will be discussed in detail.