Studies of the alpha decay of U

The decay of ²³³U through the first and second excited states of ²²⁹Th has been studied using a uranium oxide source. The half-life of the first excited state of ²²⁹Th was found to be less than 1.9 nsec; it decays by an almost pure M1 transition. The half-life of the second excited state of ²²⁹Th was found to be 0.5±0.2nsec; this level de-excites by E2 cross-over radiation in 96% of events. Contrary to expectations, an anisotropic alpha-gamma angular correlation was not found, and the probable reason for this is discussed.