Radiochemical Studies of the (p, pn) Reaction in Complex Nuclei in the 80-450-Mev Range

Excitation functions for the ($p, \mathrm{pn}$) reaction have been determined in the energy range 82 Mev to 426 Mev for the target nuclei ${\mathrm{F}}^{19}$, ${\mathrm{Cu}}^{65}$, and ${\mathrm{Au}}^{197}$. The absolute values are based on the excitation function for the reaction ${\mathrm{C}}^{12}(p, pn){\mathrm{C}}^{11}$. These excitation functions exhibit a general decrease with energy and the cross sections lie between 122 mb for ${\mathrm{Au}}^{196}$ at 82 Mev and 23 mb for ${\mathrm{F}}^{18}$ at 426 Mev. An excitation function for the reaction ${\mathrm{Al}}^{27}(p, 3pn){\mathrm{Na}}^{24}$ is also presented. The results of Monte Carlo nuclear cascade calculations have been used to predict these ($p, \mathrm{pn}$) excitation functions. The theoretical results are compared with experimental results of this and other reports. Agreement is obtained for the ${\mathrm{F}}^{19}(p, pn){\mathrm{F}}^{18}$ excitation function and an extrapolation of the Monte Carlo results. The theoretical excitation functions are about one-half the experimental results for the ${\mathrm{Cu}}^{65}(p, pn){\mathrm{Cu}}^{64}$ reaction and about one-third the experimental results for ${\mathrm{Au}}^{197}(p, pn){\mathrm{Au}}^{196}$. The effects on the Monte Carlo calculations of a variation in the radius parameter are examined.