We report on the study of the electrochemical behavior of copper and brass electrodes in concentrated aqueous KOH solutions. Passive films are formed on the surface of anodically polarized, pure polycrystalline copper and a Cu-30Zn alloy ͑␣-brass͒, in aqueous 30% ͑7 M͒ and 45% ͑11.7 M͒ KOH electrolyte solutions, at two characteristic potentials ͑corresponding to the two major anodic peaks in the voltammograms of these systems͒. The structure and composition of the films were determined by ex situ X-ray diffraction ͑XRD͒, in situ and ex situ micro-Raman spectroscopy, X-ray photoelectron spectroscopy ͑XPS͒, scanning electron microscopy ͑SEM͒, and atomic force microscopy ͑AFM͒. The formation of crystalline cubic Cu 2 O, on the surface of Cu and Cu-30Zn electrodes in highly concentrated KOH solutions, occurs at potentials above −400 mV vs a standard hydrogen electrode ͑SHE͒. A porous passive layer is formed at potentials above −150 mV vs SHE on pure Cu surfaces. In a 30% KOH solution, this surface layer consists of Cu͑OH͒ 2 , while in a 45% KOH solution, the surface films comprise a Cu 2 O/Cu͑OH͒ 2 structure with the Cu 2 Oas the inner layer. The anodic polarization of Cu-30Zn ͑␣-brass͒ leads to a complete dezincification of the surface, at potentials Ͼ−350 mV vs SHE, in both electrolyte solutions. Porous surface layers are formed on brass at these anodic potentials and have duplex structure, Cu 2 O/Cu͑OH͒ 2 , where the Cu͑OH͒ 2 content increases with an increase in the KOH concentration. At potentials Ͼ−150 mV vs SHE, the Cu͑OH͒ 2 layer shows a preferential orientation of ͑020͒.
The capability of a recently developed BGO detector system featuring a "self-collimating" structure to locate a point source was established by Monte Carlo simulations and by laboratory scale experiments. The detector system's capability to determine the direction of a nuclear plume resulting from a PWR1 or PWR2 type accident in stable atmospheric conditions by airborne monitoring of the 2.4 MeV photons emitted by 88Kr was established by Monte Carlo simulations.
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