Measurement of Cross Sections for Reactions ${}^{232}$Th(${}^{4}$He, $p5n$)${}^{230}$Pa, ${}^{232}$Th(${}^{4}$He, $p3n$)${}^{232}$Pa, ${}^{232}$Th(${}^{4}$He, $2pn+p2n$)${}^{233}$Pa, and ${}^{232}$Th(${}^{4}$He, $6n$)${}^{230}$U Induced by the Irradiation of ThO${}_{2}$ Targets with ${}^{4}$He

Abstract

At present, the radioisotope ${}^{230}$U is considered as one of the most promising $\alpha$-emitters for application in immunotherapy. In order to refine nuclear data and to evaluate the efficiency of ${}^{230}$U production, the cross sections for the reactions ${}^{232}$Th(${}^{4}$He, $p5n$)${}^{230}\textrm{Pa}\to^{230}$U and ${}^{232}$Th(${}^{4}$He, $6n$)${}^{230}$U, as well as the cross sections for the accompanying reactions ${}^{232}$Th(${}^{4}$He, $p3n$)${}^{232}$Pa and ${}^{232}$Th(${}^{4}$He, $2pn+p2n$)${}^{233}$Pa, were measured for the first time in the range of energies of ${}^{4}$He nuclei between 30 and 62 MeV. The activation technique was used to measure the reaction cross sections. The experimental cross sections were compared with data from the TENDL-2021 library. The results give grounds to conclude that the reactions ${}^{232}$Th(${}^{4}$He, $p5n$)${}^{230}\textrm{Pa}\to^{230}$U and ${}^{232}$Th(${}^{4}$He, $6n$)${}^{230}$U cannot ensure efficient production of ${}^{230}$U at the U-150 cyclotron of National Research Center Kurchatov Institute. Therefore, they cannot be viewed as an alternative to proton- and deuteron-induced reactions producing ${}^{230}$U.