PROTON ANGULAR DISTRIBUTION IN THE C<sup>12</sup>(d,p)C<sup>13</sup> AND Ca<sup>40</sup>(d,p)Ca<sup>41</sup> GROUND STATE REACTIONS

Abstract

The angular distribution and differential cross-section of the proton groups from the C12(d,p)C13 and Ca40(d,p)Ca41 ground state reactions have been measured at the deu-teron energy of 13.3 MeV. Measurements were made at 2.5° or 5° intervals and covered the angular range from 3° to 167° and from 10° to 164° for the C12 and Ca40 reactions respectively. It is found that: (1) The experimental points near the main stripping peak agree fairly well with the theoretical angular distribution curve calculated by using the simple Butler theory and normalized at the stripping peak, for both proton groups. The parameters of the nuclear levels thus determined are in good accord with the results previously obtained. (2) For large angles, the experimental cross-sections do not decrease to such small values as required by the Butler theory. They also show very prominent subsidiary maxima at the positions not in accord with the prediction of the Butler theory. These features can be interpreted by the distorted wave theory, but may also be partly due to contributions of reaction mechanisms other than the deuteron stripping. (3) In the C12(d, p)C13 reaction, the cross-section decreases strongly at the forward angle and shows an uprising at the backward angle. Neither of these features is in accord with the Butler theory, but they can also be explained by the distorted wave theory. The uprising at the backward angle may also be due to contributions of other reaction mechanisms. (4) The reduced widths of the ground levels for the C12(d, p)C13 and Ca40(d, p)Ca41 reactions, obtained from the peak cross-sections by using the Butler theory are γ2 = 0-17 and 0.041 respectively. The distorted wave theory gives larger values which will be closer to the values expected from the single particle model. Owing to these facts, it seems worthwhile to analyze the data of the present experiment with the detailed distorted wave theory.