AN APPARATUS FOR MONITORING THE RADIOACTIVITY OF A PLURALITY OF LIQUID SCINTILLATION SAMPLES DEPOSITED ON MULTI-WELL SAMPLE PLATES

摘要

The present invention shows a new apparatus in the field of the liquid scintillation counting. The apparatus counts liquid scintillation or corresponding samples directly from the sample plates (10) which comprise several separate sample wells (11) or vials. The apparatus has one or several detectors for the purpose of counting one or several samples at a time. The sample plate (10) is placed manually or automatically between photomultiplier tube assembly pair (14 a, 14 b) which works in coincidence forming the detector of the apparatus. The lower photomultiplier tube assembly (14 a) is provided with a light pipe (12). The apparatus has a moving mechanism, which can move the lower photomultiplier tube assembly (14 a) with said light pipe to up and down positions. In the up position the walls of the light pipe (12) are pressed tightly against said upper photomultiplier tube assembly (14 a) in order to form an optically closed compartment around the sample well (11) which is in the counting position. In order to prevent light from travelling between the sample wells (11) through the material of the sample plate (10) one or both surfaces between the wells (18) of the sample plate (10) are painted black or this region (18) is treated in some other way which prevents light from travelling between the sample wells (11).