Nitrogen-Induced Nuclear Reactions in Aluminum

Aluminum foils were bombarded with 25.5-Mev nitrogen ions from the Oak Ridge National Laboratory 63-inch cyclotron, and the following radioactive reaction products were separated chemically and identified: C¹¹, N¹³, F¹⁸, Na²⁴, Cl³⁸, K³⁸, and P³². The deflected cyclotron beam was used to study the cross sections for the three reactions, Al²⁷ (N¹⁴, N¹³) Al²⁸, Al²⁷(N¹⁴, 3p)Cl³⁸, and Al²⁷(N¹⁴, p2n)K³⁸, for energies from 19.5 to 25.5 Mev. It was found that over this energy range the cross section for the (N¹⁴, $p2n$) reaction is about fifty times greater than for the (N¹⁴, $3p$) reaction, as would be expected from the statistical theory for the decay of the compound nucleus. A search was made for Si³¹ and Mg²⁷. The upper limits for the respective yields are 3×{}10^-11 and 9×{}10^-11 nuclei formed per incident particle at 25.5 Mev. The range-energy relation for nitrogen ions in aluminum was measured.