A delayed-coincidence timing spectrometer system was used to experimentally measure the lifetime of the 344-keV level of 152 64Gd by means of the self comparison technique. A major objective of the study was to determine the effectiveness of a NaI(Tl)-plastic detector assembly for energy spectrum reconstruction when measuring the lifetime of a level in a complex nuclear decay scheme. The experimentally measured mean life was 38 ± 5 psec. This result does not agree with two previously reported values of 76 psec. It was concluded that gamma-ray energy misidentification was primarily responsible for the disagreement. Correction factors would have to be applied to the experimental data is such a system is to be effective in a nuclear decay scheme study which involves many gamma rays.Ball State UniversityMuncie, IN 47306