The 8Li Calibration Source for the Sudbury Neutrino Obervatory

A calibration source employing 8 Li (t 1 / 2 = 0.838 s) has been developed for use with the Sudbury Neutrino Observatory (SNO). This source creates a spectrum of beta particles with an energy range similar to that of the SNO 8 B solar neutrino signal. The source is used to test the SNO detector’s energy response, position reconstruction and data reduction algorithms. The 8 Li isotope is created using a deuterium-tritium neutron generator in conjunction with a 11 B target, and is carried to a decay chamber using a gas/aerosol transport system. The decay chamber detects prompt alpha particles by gas scintillation in coincidence with the beta particles which exit through a thin stainless steel wall. A description is given of the production, transport, and tagging techniques along with a discussion of the performance and application of the source.