Reexamination of the Optical Gamma Ray Decay in T 229 h

Optical measurements of a clean, 2−μC 233U sample were made to verify light emission from gamma ray decay of the first excited nuclear level in 229Th. The results showed that the light observed in earlier studies was likely to be caused by alpha-particle induced fluorescence of air. In vacuo, no light emission was discernable. The 229Th system, therefore, does not appear to provide the level of access for studying atomic-nuclear interactions suggested by the previous measurements.