Trace determination of boron, silicon and sulfur with oxygen-18 ion bombardment

In order to determine traces of boron, silicon and sulfur, B(18O,x)27Mg, Si(18O,x)43Sc and S(18O,x)47V reactions have been investigated between 15 and 44 MeV. At 34 MeV, only a few of the systematically identified nuclear interferences produce 27Mg and the detection limit is 30 ng boron for a 10 minute irradiation with a 0.3 μAxcm-2 oxygen-18 beam. Silicon analysis has shown nuclear interferences from Al, P and K, the interference-free detection limit is 80 ng silicon for an hour irradiation with a 0.4 μAxcm-2 beam at 39 MeV. There is no nuclear interference for the sulfur determination and the detection limit is 5 ng sulfur for a 30 minute irradiation with a 0.5μAxcm-2 beam at 39 MeV. Thus a selective and sensitive sulfur determination can be achieved. (author)