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Abstract
The E2 Nuclear Resonance Effect was studied using $\sp{150}$Sm and $\sp{152}$Sm, the former being a resonant isotope and the latter being non-resonant. By measuring the attenuation of x-ray intensity in the resonant isotope compared to the non-resonant isotope, a measure of the induced width in the upper admixed level due to antiproton absorption from the lower admixed level was found. The results obtained showed that the level widths measured experimentally were, for the upper level, broader than one would expect from theoretical calculations, indicating that the strong interaction is greater than one might expect for this antiproton-nucleus system. However, direct measurements of the width of a transition between low lying states (i.e. those of low principle quantum number, n) indicate that the reverse is true for these states. Here the measured width was rather less than theoretical predictions, indicating less strong interaction effects for such states that probe further into the nucleus.
By measuring x-rays and gamma-rays emitted from a lead target after antiproton irradiation over a period of time the species created by antiproton absorption were identified and their abundances were calculated. The distribution of residual nuclei had the same general shape as that obtained from theoretical calculations using an intra-nuclear cascade approach followed by an evaporation process. The maximum of the experimental curve was at a higher atomic mass than the theoretical curve, indicating the possibility that too great an energy transfer between the system of pions created in the annihilation process and the nucleons in the lead nucleus is used in the theoretical calculations. Much care was spent in looking for fission following the deposition of some 2 GeV in the lead nucleus from the annihilation process, but no evidence could be seen.
