Energy spectra of neutrons produced by α-particles in thick targets of light elements

Energy spectra of neutrons produced by 4–5.5 MeV α-particles in thick targets of C, Mg, Al, Si, BN, CaF₂, Al₂O₃, SiO₂ and UO₂ have been determined. A Van de Graaff accelerator has been used as a pulsed α-particle source and neutrons were detected at 0, 30, 60, 100 and 140° by a calibrated NE 213 scintillator used as a time-of-flight spectrometer. Angle-integrated spectra were derived not only for the above materials but also for B, F and O. Energy integration delivers yields in good agreement with recent results from 4π moderator detector measurements.