Copper-64 production studies with natural zinc targets at deuteron energy up to 19 MeV and proton energy from 141 down to 31 MeV

High specific activity no-carrier-added 64Cu is a β-/β+ emitting radionuclide of increasing interest for PET imaging, as well as systemic and targeted radioimmunotherapy of tumors. Its peculiarity of intense Auger emitter is still under investigation. The cross-sections for prodn. of 64Cu from Zn target of natural isotopic compn. were measured in the deuteron energy range from threshold up to 19 MeV and proton energy range from 141 down to 31 MeV. The stacked-foil technique was used at both K = 38 cyclotron of JRC-Ispra of CEC, Italy and 160 MeV intersection point of NIR proton-LINAC in Troitsk, Russia. Several Ga, Zn, Cu, Ni, Co, V, Fe and Mn radionuclides were detected in Zn targets at the EOB. Optimized irradn. conditions are reported as a function of deuteron energy and energy loss into the Zn target, as well as target irradn. time and cooling time after radiochem. The activity of n.c.a. 64Cu was measured through its only y emission of 1346 keV (i.e., 0.473 intensity) both by instrumental and radiochem. methods, due to the non-specificity of annihilation radiation at 511 keV. To this last purpose, it was necessary to carry out a selective radiochem. sepn. of Ga(III) radionuclides by liq./liq. extn. from the bulk of irradiated Zn targets and other spallation products, which remained in the 7 M HCl aq. phase. Anion exchange chromatog. tests had been carried out to sep. the 60Cu from all others radionuclides in n.c.a. form. Theor. calcns. of cross-sections were performed with codes EMPIRE II and PENELOPE for deuteron reactions and CEF model and HMS-ALICE hybrid model for proton reactions. The theor. results are presented and compared with the exptl. values.