Determination of Tritium-Helium-3 differential cross-section in the energy range between 0.6 MeV and 3.3 MeV for tritium depth profiling in solids

Abstract

The differential cross-section for the 3He+3H nuclear reaction was measured in a thin tritiated PdTi film that was deposited on a Si wafer. The sample was loaded with 3H2 gas at a temperature of 300 °C and at a pressure of 1.8 bar. The total activity of the sample, measured by the liquid scintillation technique, was found to be 395 MBq. Two peaks were observed in the spectrum of the thick Si detector, corresponding to the 3H(3He,d)4He and 3H(3He,p)5He reaction channels. The differential cross-section was determined for the energy range of the 3He beam from 0.6 to 3.4 MeV, at three scattering angles of 125, 135 and 155°. The differential cross-section for the first channel remained almost constant within the measured energy range, while the cross-section for the second channel increased with energy. In both cases, the cross-sections reached their maximum value at the lowest scattering angle measured. The differential cross-sections were verified using a thick solid tritiated tungsten target. For assessing the tritium depth profile, only the reaction channel 3H(3He,d)4He can be utilized.