Compact High Resolution Isobar Separator for Decay Spectroscopy

A compact isobar spectrometer and separator, based on the Multi-Pass-Time-of-Flight (MTOF) principle, is being developed by the University Radioactive Ion Beam (UNIRIB) Consortium. Using N$_{2}$ as sample gas, a mass~resolving power of 113,000 (FWHM) and a transmission of $\sim $ 50 {\%} have been achieved after a time-of-flight of 9.7 ms. Coupled to the UNISOR mass separator at HRIBF, MTOF will provide isotopically pure samples of species around $^{100}$Sn, of neutron deficient rare-earth nuclei and of neutron-rich nuclei for use in decay studies and mass measurements. With beam cooling and bunching, we expect a mass resolving power (FWHM) of $\sim$ 400,000, transmission of $\sim $25 {\%} and isobaric suppression of adjacent elements $\sim $ 40,000. As a by product, MTOF will determine the masses of nuclei investigated with accuracies of 10$^{-6}$ , or about 100 keV for a mass A = 100 nucleus. Spectra demonstrating the separation of stable nuclides using a Bradbury-Nielsen gate will be shown.