1.1 ,This non-destructive test method detects leaks in non-porous rigid thermoformed trays, as well as the seal between the porous lid and the tray. The test method detects channel leaks in packages as small as 100 μ,m (0.004 in.) diameter in the seal as well as 50 μ,m (0.002 in.) diameter pinholes, or equivalently sized cracks in the tray, subject to trace gas concentration in the package, package design and manufacturing tolerances.