The Sudbury Neutrino Observatory is a second-generation water Cherenkov det
ector designed to determine whether the currently observed solar neutrino d
eficit is a result of neutrino oscillations. The detector is unique in its
use of D2O as a detection medium, permitting it to make a solar model-indep
endent test of the neutrino oscillation hypothesis by comparison of the cha
rged- and neutral-current interaction rates. In this paper the physical pro
perties, construction, and preliminary operation of the Sudbury Neutrino Ob
servatory are described. Data and predicted operating parameters are provid
ed whenever possible. (C) 2000 Elsevier Science B.V. All rights reserved.