  Using a mulit-reflection time-of-flight mass spectrograph (MRTOF-MS) located
after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the
masses of several heavy nuclei have been directly and precisely measured. The
nuclei were produced via fusion-evaporation reactions and separated from
projectile-like and target-like particles using GARIS-II before being stopped
in a helium-filled gas cell. Time-of-flight spectra for three isobar chains,
205Fr-205Rn-205At-205Po, 206Fr-206Rn-206At and 201Rn-201At-201Po-201Bi, were
observed. Precision atomic mass values were determined for 205,206Fr, 201At,
and 201Po.
