Atmospheric neutrino interactions in Soudan-2

A new measurement of the atmospheric numu/nue ratio-of-ratios, 0.61 ± 0.15 ± 0.05, has been obtained using a 3.2-kty exposure of the Soudan-2 underground detector. This measurement, based upon neutrino reactions in an iron tracking calorimeter of honeycomb-lattice geometry, is in agreement with the anomalously low value reported by the underground water detectors.