Abstract
The intensity of the reaction is observed to vary with angle as , as expected from the Bose statistics of the product alphas, with rising gradually beginning just below 1 Mev to a broad maximum a little below unity at a bombarding energy in the neighborhood of 2 Mev. The coefficient remains zero up to almost 1.5 Mev and rises to a positive value of about 0.35 at higher energies. The yield curve observed at right angles to the beam displays a sharp maximum at 0.75 Mev and there is evidence of approach to another peak at or just beyond the highest bombarding energy employed, 3.75 Mev. The substitution of a proportional counter for the ionization chamber used in earlier work has made possible improvement over our earlier observations of the angular distribution of the reaction in the neighborhood of 3 Mev, where difficulty was experienced in the discrimination against pile-up of scattered protons, and the new results show a node in the curve for at 2.7 Mev. A peak in the yield curve of this reaction is found at 3 Mev, which is about 3 Mev lower in the compound nucleus than the lower peak observed in the reaction . There is great similarity in the trends of the angular distributions of the two reactions, but their coefficients have opposite signs in the energy regions investigated, and both and rise from zero more gradually in than in as the bombarding energy increases from low values.
- Received 10 May 1948
DOI:https://doi.org/10.1103/PhysRev.74.405
©1948 American Physical Society