Time-of-Flight Mass Measurement of Exotic Nuclei Near N=28 Shell Closure Around Sulfur

Nuclear masses of neutron-rich nuclides are important for understanding the processes occurring in the crust of accreting neutron stars and the evolution of nuclear shell closures towards the neutron drip-line. The time-of-flight (TOF) magnetic-rigidity (B$\rho$) technique offers access to these short-lived exotic nuclei. In the recent TOF-B$\rho$ experiment at the National Superconducting Cyclotron Laboratory (NSCL), the projectile fragmentation of $\rm ^{48}{Ca}$ was used to produce the isotopes of interest below argon near the $\rm ^{46}{S}$ region. We measured the nuclear masses of $\rm ^{42}{Si}$, $\rm ^{44}{P}$, and $\rm ^{46}{S}$ which have not been determined experimentally so far. The mass of $\rm ^{46}{S}$ will help to measure the strength of the shell gap at the N=28 and the mass of $\rm ^{42}{Si}$ will allow the determination of the electron capture Q-value for the $\rm ^{42}{P}(EC)^{42}{Si}$ reaction. The current status of the data analysis and the preliminary results of this experiment will be discussed.