Monopole-flux and proton-decay limits from the Soudan 1 detector

Final results are presented from the search for magnetic monopoles and nucleon decay in the Soudan 1 detector, a 31.4-metric-ton tracking calorimeter located underground at a depth of 590 m. A detailed description of the detector is given. The possible existence of monopole catalysis of nucleon decay has been systematically incorporated into the analysis. During a live time of 1.0 yr, no candidates for grand-unified magnetic monopoles were observed, leading to 90%-confidence-level flux limits near ${10}^{\mathrm{-}13}$ ${\mathrm{cm}}^2$ sec sr.