| 摘要 |
<p>The invention relates to an arrangement and a method for measuring level, interface level and/or density profile of at least one fluid located in a tank or container (2, 3) by the aid of at least two nuclear radiation sources (9) vertically arranged at a predetermined distance from each other inside or both inside and outside the tank and a detector unit (11), which are located at a suitable distance from each other and inserted into separate protection pipes (8, 10). The detector unit (11) comprises a long vertical detector in the form of a scintillator rod (12) covering the total height in the tank or the container (2, 3) having a photo multiplier tube (13) at each end and associated electronics that provides both information on position as well as radiation level at different positions along the scintillator rod (12) by measuring pulse amplitudes measured from the photo multiplier tube. According to the method the radiation absorbed from the radiation sources (9) takes place in the scintillator rod (12) forming the detector unit (11) by the aid of the photo multiplier tubes (13) at each of its ends, which transform the radiation to electric pulses having an amplitude proportion to the light intensity of the radiation at the actual position along the rod (12), whereby the amplitude is measured electronically on the two simultaneous pulses and a ratiometric calculation is then used to determine the position of the corresponding radiation quant.</p> |
