New Isotopes in Neutron Rich Hf-Lu Region via Fragmentation of ¹⁹⁸Pt

The properties of neutron rich heavy isotopes are fundamentally important to various aspects of nuclear physics including the r-process in astrophysics, N=126 shell closure, and heavy ion fragmentation reactions. Despite the interest, this region is largely unexplored; only a few N=126 isotopes of elements lighter than lead have been produced and identified. In order to establish a footing in this region and eventually reach out toward the location of the r-process pathway and beyond, an experiment was performed at NSCL to study production of neutron rich isotopes in the Hf-Os region.

A 86 MeV/u 198Pt beam was incident on both Beryllium and Nickel targets producing fragments that were separated with the A1900. A scintillator at the focal plane of the A1900 separator recorded the time of flight stop signal. The start signal, energy loss, position (strip detector), and total kinetic energy was measured with a pin diode telescope at the final dispersive focus of the S800 spectrograph. Once particle ID was complete, cross sections were calculated using LISE++ to estimate the transmission of each fragment through the A1900 + S800 setup.

Several new isotopes, details/methods of particle ID in an exotic heavy isotope region, and precision of cross section calculations will be discussed.