77 Br / 80m Br / Intermediate energy / Proton induced reaction / Excitation function / Integral yield / Radionuclide production Summary. The two Auger electron emitting radionuclides of bromine, namely 77 Br (T 1/2 = 57.04 h) and 80m Br (T 1/2 = 4.4 h), are promising candidates for internal radiotherapy. In this work, nuclear reaction cross sections were determined for their production using enriched Se targets. Thin Se samples were irradiated with incident protons of energies up to 85 MeV and the induced radioactivity was measured via nondestructive γ -ray spectroscopy, allowing the determination and extension of the excitation functions of the four reactions 77,78,80 Se( p, xn) 77 Br and 80 Se( p, n) 80m Br. The possible thick target yields were calculated and the different production routes discussed, especially with regard to the yield and the radionuclidic purity of the produced radionuclides.