2.1.2. Photonuclear Production

The photonuclear production for <sup>67</sup>Cu using bremsstrahlung photons with an e-LINAC accelerator has been studied for decades [29–36]. Recently, a large enriched <sup>68</sup>Zn target (55.5 g) was irradiated with 40 MeV e-LINAC for 53.5 h, obtaining 62.9 GBq (1.7 Ci) without detecting <sup>64</sup>Cu [10]. The threshold energy of the <sup>68</sup>Zn(γ,x)64Cu reaction is ETHR = 27.6 MeV [37]. For the photonuclear reaction, the use of enriched target material is mandatory to avoid the coproduction of the following radionuclide impurities: <sup>63</sup>Zn, <sup>65</sup>Zn, and <sup>64</sup>Cu. According to the DOE Isotope Program, <sup>67</sup>Cu is being routinely produced by the Argonne National Laboratory via a photonuclear reaction at its low-energy accelerator facility (LEAF). Approximately 1 curie per batch can be provided, with radionuclidic purity of >99% and a specific activity >1850 GBq/mg (>50 Ci/mg) <sup>67</sup>Cu/total Cu at EOB [38]. Commercial entities have indicated they are pursuing this route of production, although no commercial suppliers are online as of the date of this publication.
