1266-KEV GAMMA BRANCH IN SI-31 DECAY

We have measured the absolute gamma-ray intensity, i.e., gamma's per 1 00 parent decays, of the 1266-keV line produced in Si-31 decay using n eutron activation and delayed photon spectroscopy. Its value was deter mined to be 0.050+/-0.004%. This result is lower than the only previou sly reported value of 0.07, which was given without an uncertainty. In a separate experiment to validate the method of measurement and analy sis, the gamma-ray intensity of the 1779-keV line of Al-28 was determi ned to be 98+/-8.8%, in good agreement with its adopted value of 100%.