Measurement of the beta-resonant gamma angular correlation in As76

The beta-resonant gamma angular correlation existing between the beta particles and the gamma rays associated with the decay sequence As76 → 2.41 MeV beta + 0.559 MeV gamma + Se76 has been measured. This measurement has been accomplished by observing the coincident detection of 2.41 MeV betas and those 0.559 MeV gamma rays which are subsequently scattered through a nuclear resonant scattering process by Se76. The partial equivalence of this measurement and the, probably impossible, direct measurement of the beta-neutrino angular correlation for this decay process is discussed. In addition, the use of this type of experiment as an aid in helping to eliminate sets of nuclear matrix elements which are otherwise compatible with data from the experiments which are normally used to obtain a unique set of nuclear matrix elements for a given beta decay process is discussed. The results of this measurement tend to favor those otherwise experimentally compatible nuclear matrix element sets which emphasize beta neutrino emission in opposite directions as opposed to those favoring emission of the beta and neutrino in the same direction