High-precision mass measurement of N = Z = 34 nuclides for RP-process simulations and developments for the LEBIT facility

The Low Energy Beam and Ion Trap (LEBIT) facility at the National Superconducting Cyclotron Laboratory (NSCL) performs high precision mass measurements of rare isotopes. Within this work mass measurements in the N ≈ Z ≈ 34 region were performed by Penning trap mass spectrometry. Mass measurements of nuclei in this region are important for understanding the rp process, a driving mechanism behind type I x-ray bursts. The masses measured were 68Se, 70Se, 70mBr, and 71Br and experimental uncertainties ranging from 0.5 keV for 68Se to 15 keV for 70mBr were achieved. Using the LEBIT results along with theoretical Coulomb displacement energies [1] more reliable mass predictions were obtained for 70Kr and 71Kr. The new and improved data were used as input for rp process network calculations. An increase in the effective lifetime of the waiting point nucleus 685se was observed, thus confirming it as a large source of delay in the rp process. More precise information was also obtained on the luminosity during a type I x-ray burst and on the distribution of the final abundances after a burst.;Beam manipulation and detection are an important part of the high precision mass measurement process performed at the LEBIT facility. Several upgrades to the LEBIT facility for improved beam quality, control, and observation are presented. The properties of ion pulses ejected from the facility's beam cooler and buncher were investigated and optimized for improved contaminant ion detection and removal. To increase the ion detection efficiency after the Penning trap a multichannel plate detector was implemented in a Daly detector configuration. These upgrades were instrumental in moving the LEBIT facility towards measurements of nuclei with lower yields and higher levels of contaminant.