Precision Penning Trap Mass Spectrometry of $^{32}$S, $^{84,86}$Kr and $^{129,132}$Xe

Using a phase coherent technique to measure the cyclotron frequency of single ions in a Penning trap [1], we have performed mass measurements on $^{32}$S and the two most abundant krypton and xenon isotopes $^{84}$Kr, $^{86}$Kr, $^ {129}$Xe and $^{132}$Xe, to relative precisions of 0.1 ppb. This is a factor of $\sim$10-100 improvement in precision over current values [2]. [1] M.P. Bradley, J.V. Porto, S. Rainville, J.K. Thompson, and D.E. Pritchard, PRL \textbf{83}, 4510 (1999). [2] G. Audi, A.H. Wapstra, and C. Thibault, Nucl Phys \textbf{A729}, 337 (2003).