Cross-section measurements and production of 72Se with medium to high energy protons using arsenic containing targets

Experiments were performed to evaluate production of Se-72, parent radionuclide of the positron emitter As-72, at high energy at the Brookhaven Linac Isotope Producer (BLIP). Excitation functions for As-75(p, xn)Se-72/75 in the 52-105 MeV energy range were measured by irradiating thin gallium arsenide (GaAs) wafers. Maximum cross section value for the As-nat(p, 4n)Se-72 reaction in the energy range was 103 +/- 9 mb at 52 +/- 1 MeV. Production size GaAs and arsenic metal (As degrees) targets were irradiated with 136 mu A and 165 mu A beam current possessing an initial Linac energy of 117 MeV. A total of 3.77 +/- 0.1 GBq (102 +/- 3 mCi) of Se-72 was produced from a GaAs target at a calculated target entrance energy of 105.4 MeV, and 13.8 +/- 0.3 GBq (373 +/- 8 mCi) of Se-72 from an As degrees target at a calculated incident energy of 49.5 MeV irradiated for 116.5 h and 68.9 h, respectively.