Abstract: High efficiency, low cost solar energy conversation is facilitated by using tubular photovoltaic solar cells situated at the focus of a line-generated paraboloidal reflector. Advantageously each solar cell comprises a pair of concentric glass tubes that are hermetically sealed at the ends. A photovoltaic junction is formed over the entire inside surface of one of the concentric tubes. For example, this may comprise an inner electrically conductive film, contiguous layers of Cu.sub.2 S and CdS forming a heterojunction, and an outer film of optically transparent but electrically conductive material. The conductive films provide electrical connection to the junction via external contacts that are symmetrically disposed at the ends of the tubular cell.In other embodiments the photovoltaic junction is formed in a crystalline silicon layer that is grown in situ on one of the glass tubes. Techniques for promoting oriented semiconductor crystalline growth are disclosed.

Abstract: The spectral response of a photovoltaic cell is controlled by modifying the minority carrier transport characteristics of the cell semiconductor body. Recombination centers are provided in the body that reduce the lifetime or diffusion distance of minority carriers. Thus a reduced percentage of minority carriers produced deep in the body by absorption of relatively long wavelength photons reach the cell junction, as compared with carriers produced at lesser depth by absorption of shorter wavelength photons. The result is a shift in the peak spectral response of the cell toward shorter wavelengths.

Abstract: Photo-Darlington devices having a response within a narrow range of current output for a certain illumination level are produced by initially providing each device with a light-admitting opening of smaller than requisite size. The device outputs are measured separately, and based on such measurements, the individual openings are enlarged sufficiently so that the output current from each device falls within the requisite range.For improved performance, each photo-Darlington device has a pair of emitters spaced on opposite sides of the light admitting opening. This provides better efficiency and results in more consistent output despite non-uniform illumination of the device.

Abstract: High efficiency, low cost solar energy conversion is facilitated by using tubular photovoltaic solar cells situated at the focus of a line-generated paraboloidal reflector. Advantageously, each solar cell comprises a pair of concentric glass tubes that are hermetically sealed at the ends. A photovoltaic junction is formed over the entire inside surface of one of the concentric tubes. For example, this may comprise an inner electrically conductive film, contiguous layers of Cu.sub.2 S and CdS forming a heterojunction, and an outer film of optically transparent but electrically conductive material. The conductive films provide electrical connection to the junction via external contacts that are symmetrically disposed at the ends of the tubular cell.In other embodiments the photovoltaic junction is formed in a crystalline silicon layer that is grown in situ on one of the glass tubes. Techniques for promoting oriented semiconductor crystalline growth are disclosed.

Abstract: A method and apparatus for seismic geophysical exploration including a seismic energy source, a control means, a plurality of geophones, and a plurality of geophone monitoring means, all located in a selected survey area. Each geophone monitoring means is positioned in relatively close physical proximity and electrically coupled to one or more of the geophones forming a set of geophones. The control means is utilized to generate electrical signals containing data initiating the operation of the seismic energy source and the plurality of geophone monitoring means. The electrical signals generated by the various geophones in a set responsive to a particular shot of the seismic energy source are received by the associated geophone monitoring means. Apparatus contained within the associated geophone monitoring means samples such geophone signals and produces representative data in digital form. The digitized data is stored in a memory device contained within the geophone monitoring means.

Abstract: A detector for tubular transparent articles employs a light beam directed across an opening in a housing, along a path offset from a diameter of that opening. When a tubular article is present in the opening, the light is glazingly deflected by a curved surface of the article, optimally at the critical angle of maximum light reflection. The resultant reduction in beam intensity is sensed by a photodetector to indicate the presence of the article.