Excitation functions and isomeric cross section ratios of the 63Cu(n, alpha )60Com,g, 65Cu(n, alpha )62Com,g, and 60Ni(n,p)60Com,g processes from 6 to 15 MeV.

Excitation functions were measured for the {sup 63}Cu({ital n},{alpha}){sup 60}Co{sup {ital m}}, {sup 65}Cu({ital n},{alpha}){sup 62}Co{sup {ital m}}, and {sup 65}Cu({ital n},{alpha}){sup 62}Co{sup {ital g}} reactions over the neutron energy range of 6.3 to 14.8 MeV. Use was made of the activation technique in combination with high resolution {gamma}-ray spectroscopy. The nuetrons were produced via the {sup 2}H({ital d},{ital n}){sup 3}He reaction using a deuterium gas target at a variable energy compact cyclotron ({ital E}{sub {ital n}}=6.3--11.9 MeV) and via the {sup 3}H({ital d},{ital n}){sup 4}He reaction using a solid Ti-T target at a neutron generator ({ital E}{sub {ital n}}=13.7--14.8 MeV). From the available experimental data isomeric cross section ratios were determined for the isomeric pair {sup 60}Co{sup {ital m},}{ital g} in {sup 63}Cu({ital n},{alpha}) and {sup 60}Ni({ital n},{ital p}) reactions, and for the pair {sup 62}Co{sup {ital m},}{ital g} in the {sup 65}Cu({ital n},{alpha}) reaction. Statistical model calculations taking into account precompound effects were performed for the formation of both the isomeric and ground states of the products. The calculational results on the total ({ital n},{ital p}) and ({ital n},{alpha}) cross sections agree well with the experimental data; in the case of isomeric states, however, some deviations occur. Themore » experimental isomeric cross section ratios are reproduced only approximately by the calculation; at 15 MeV the spin distribution of the level density has a significant effect on the calculation. For low-lying levels the isomeric cross section ratio depends strongly on the spins of the levels involved and not on their excitation energies. At a given neutron energy the population of the higher spin isomer appears to be higher in the ({ital n},{alpha}) process than in the ({ital n},{ital p}) reaction.« less