Measurements of Masses with the Canadian Penning Trap*

The primary focus of the Canadian Penning Trap (CPT) located at Argonne National Laboratory is to determine the masses of various isotopes relevant to the $r $process, an astrophysical process thought to be responsible for the creation of half the elements heavier than iron. Currently, the CPT is operating in conjunction with the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) at Argonne National Laboratory's ATLAS facility in an attempt to measure neutron-rich nuclei produced by a 1.0 Curie source of $^{\mathrm{252}}$Cf. The mass measurements of these nuclei are accomplished by measuring the cyclotron frequency of the isotopes captured in the trap. This frequency is measured with a position-sensitive microchannel plate (MCP), which records the relative position of the isotope in the trap for different phase accumulation times. This summer, the CPT group was able to successfully measure to a precision of 10 keV/c$^{\mathrm{2}}$ the masses of $^{\mathrm{142}}$I and $^{\mathrm{156,158,159}}$Nd, which are key nuclei needed to more accurately model the $r $process. This also marks the first time that any of these nuclei had ever been measured.