Production of ⁶⁷Cu by enriched ⁷⁰Zn targets: first measurements of formation cross sections of ⁶⁷Cu, ⁶⁴Cu, ⁶⁷Ga, ⁶⁶Ga, ^69mZn and ⁶⁵Zn in interactions of ⁷⁰Zn with protons above 45 MeV

Abstract

Abstract Despite its insufficient availability, Copper-67 is currently attracting much attention for its enormous potential for cancer therapy as theranostic radionuclide. This work aims to accurately measure the unexplored cross section 70 Zn(p,x) 67 Cu in the energy range 45–70 MeV and to evaluate its potential advantages in the case of high-intensity proton beams provided by compact cyclotrons. Thin target foils of enriched 70 Zn were manufactured by lamination at the INFN-LNL and irradiated at the ARRONAX facility using the stacked-foils method. A radiochemical procedure for the separation of Cu, Ga and Zn contaminants and the isolation of 67 Cu from the irradiated material was developed. The efficiency of the chemical processing was determined for each foil by monitoring the activity of selected tracer radionuclides ( 61 Cu, 66 Ga and 69m Zn) through γ-spectrometry. Experimental data of the 70 Zn(p,x) 67 Cu, 64 Cu, 67 Ga, 66 Ga, 69m Zn, 65 Zn cross sections were measured for the first time in the energy range 45–70 MeV and compared with the theoretical results obtained by using the TALYS code. The 67 Cu production yield by using enriched 70 Zn thick targets was compared with the results obtained by using 68 Zn targets in the same irradiation conditions.