Delayed coincidence techniques show promise of significant improvements for a Xe counting system which will be a key element in monitoring the Comprehensive Test Ban Treaty. We have previously developed a beta-gamma counting system for 1 3 1 m Xe, 1 3 3 m Xe, 1 3 3 g Xe, and 1 3 5 g Xe as part of an automated system for analyzing Xe in air. Depending on background levels, higher sensitivity for 1 3 3 g Xe can be achieved by use of the delayed coincidence between beta particles that feed the 81 keV state in 1 3 3 Cs and the conversion electrons produced in the deexcitation of the 81 keV state (t 1 2 = 6.36 ns). In the delay time region, only the 31 keV X-ray associated with 1 3 3 g Xe decay is observed. This technique detects 1 3 3 g Xe with extremely low background and distinguishes 1 3 3 g Xe from 1 3 1 m Xe and 1 3 3 m Xe.