Emission Probability of the 312-keV Gamma Ray from the Decay of Protactinium-233

The emission probability of the 312-keV gamma ray from the decay of 27-day ²³³Pa has been measured. A 4π beta-gamma coincidence counting system was used to determine the ²³³Pa sample disintegration rates, and Ge(Li) spectrometers were used to measure the gamma-ray emission rates. The resulting value for the emission probability is I_γ (312 keV) = (38.6 ± 0.5) photon/100 decays. The relative intensities of the K x rays and gamma rays emitted in the decay of ²³³Pa were also measured.