| 摘要 |
An improved system for detection and analysis of microscopic flaws in objects such as high-speed turbine blades collimates the gamma radiation emanating from flaws in an object treated with a radioactive gas, preferably xenon-133, to form a gamma-photon virtual image of a surface of the object showing flaws therein. A scintillation plate transforms the gamma-photon virtual image into a photoelectron virtual image. A chevron microchannel plate pair (MCP) multiplies the number of electrons comprising the photoelectron virtual image by a factor of at least 105. The multiplied photoelectron virtual image can be converted to visible output information relatable to the flaws in the object by directing it onto a phosphor-coated plate. The scintillator, microchannel plate multiplier, and phosphor plate are contained in a housing shielded with lead to screen out signal noise from cosmic radiation. The housing is subjected to a pressure of about 10-7 Torr. Electromagnetic fields within the housing drive photoelectrons carrying the virtual image from the scintillator through the microchannel plate multiplier and into the phosphor plate, creating the visible image showing the flaws. The visible image can be viewed or photographed through a window in the rear of the housing, or it can be digitized by a video translator such as a charge-coupled device (CCD) camera for computerized image analysis. Alternatively, if output information in the form of a digitized image or data printout is desired, the phosphor plate can be omitted and the multiplied photoelectron virtual image can be digitized directly by the translator.
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