top-entry type EDS detector

An EDS detector which is placed above the objective lens with a viewing angle of about 70° to a specimen set horizontally. Since X-rays coming to the detector take a large angle against the specimen surface, the diffusion length of the emitted X-rays in the specimen is kept small without any specimen tilt, leading to a high accuracy of quantitative analysis. However, since the detector is distant from the specimen, the solid angle of the detector against the specimen is small or its detection efficiency is not high. Since the detector takes X-ray signals from the top of the objective lens, it requires a large bore polepiece for the lens. The use of such a polepiece is unfavorable to obtain a high resolution image and a small probe size on the specimen. Due to these disadvantages, this type detector has not been used recently.

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