Injection of a uniform 24Na radioactive source into the Sudbury Neutrino Observatory

A solution of 24Na was prepared, dissolved and uniformly mixed into the D2O of the Sudbury Neutrino Observatory. This calibration will be used to understand the neutral current detector array response and to determine the array's overall efficiency. The source's activity was measured in four ways. In-situ using the photomultiplier array and the newly installed 3He neutron detectors. Ex-situ using two ultra-pure germanium detectors. One located underground in the SNO laboratory, the other at Guelph University. The average strength from these measurements is 12.70 ± 0.49 MBq at the time of activation. The analysis shows that the source was uniformly distributed at the start of data taking and that the data is consistent with other neutron sources, and verified by Monte Carlo. (author)