A new experiment on the ²H(α,γ)⁶Li reaction

The ²H(α,γ)⁶Li cross section has been measured by in-beam gamma-spectrometry at the deep underground 400 keV LUNA accelerator in Italy's Gran Sasso laboratory. An α-beam of 280-400 keV energy was incident on a windowless deuterium gas target, and the γ-rays from the reaction were detected in a large high-purity germanium detector. Due to elastically scattered deuterons, there is a low but not negligible parasitic neutron production of the order of 10 neutrons per second. These neutrons give rise to a significant background in the germanium detector. In addition to the underground in-beam experiment, also studies using americium-beryllium and deuterium-deuterium neutron sources and Monte Carlo simulations have been performed. The analysis of signal and background is described in detail.