Determination of excitation functions of natSb(p,x) reactions with 30-46 MeV protons

In order to optimize the production of 118Te in thick targets for use in a 118Te/118Sb radionuclide generator, the excitation function for the 121Sb(p,4n)118Te reaction has been measured for 30-46 MeV protons. The excitation functions for the competing reactions natSb(p,xn)119mTe, na1Sb(p,pxn)120mSb, 123Sb(p,pn)122Sb and na1Sb(p,xn)121mTe have also been determined using stacked foil techniques. Thin antimony targets were prepared by electrically sputtering antimony onto the surface of metal backing foils. Target mass was determined by neutron activation analysis. High-resolution gamma-ray spectrometry was used to monitor the induced radioactivities in the activated samples. The experimental excitation functions were compared with available theoretical models and agree quite favorably. The 121Sb(p,4n)118Te reaction cross section maximum was found to be 460 millibarns at 45 MeV. Regression coefficients for the observed excitation functions were used to calculate the thick target yield for each reaction. In order to minimize the 119mTe interference a target thickness of less than 0.9 g/cm2 should be used for 46-MeV incident protons.