Array of low-background He-3 proportional counters for the Sudbury Neutrino Observatory - Amsbaugh, J; Anaya, J; Banar, J; Bowles, T; Browne, M; Bullard, T; Burritt, T; Cox-Mobrand, G; Dai, X; Deng, H; Di Marco, M; Doe, P; et al. (2007)