| 摘要 |
A pick-up is provided for a measuring device used to measure the moisture content, the filler content or the content of coating material of a paper web or the like. The measuring takes place by the X-ray fluorescence method. The pick-up has a radiation source which is ring-shaped and is located on the same side of the paper web as the detector which is located behind the radiation source. The invention is particularly characterized by the provision of a ring-shaped radiation shield placed between the radiation source and the window of the detector. The dimensions of the radiation shield are so selected that a flat-top maximum is produced in a characteristic curve indicating the dependence of the measuring signal from the distance between the radiation source and the backing material, other characteristics remaining constant.
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