Determination of the Spin and Parity of Nuclear Excited States by the Experimental Measurement of Triple Correlations in (P, gamma-gamma) Reactions

摘要

The measurement of triple correlations in (p, gammagamma) reactions to determine spin and parity of nuclear excited states has not been widely used in the past, despite the capability of such measurements to produce generally unambiguous assignments, because of the low efficiency, the complexity, and the difficulty of such measurements when performed by standard techniques. An experimental arrangement is described which allows the measurement of triple correlations with an exceptionally high efficiency and multiplicity (the capability of measuring many different correlations simultaneously). This improvement has been obtained primarily from the successful application of a three-crystal double sumcoincidence spectrometer. An explanation of the method and detailed descriptions of the physical apparatus, electronic circuitry, experimental procedures, and data analysis are given. The results of an extensive triple correlation experiment on the 60Ni)(p, gamma-gamma)61 Cu reaction are presented with the conclusions regarding the spin and probable parity of six of the lowest-lying energy levels and a discussion of the applicability of certain nuclear models to this nucleus. (Author)