Radiation measuring device, particularly for luminescence measurements

In a radiation measuring device for performing measurements on samples contained in a plurality of sample containers, the apparatus including a radiation detector having an entrance window, sample container holding means defining a sample container holding region for holding a plurality of sample containers in a matrix pattern, and displacement devices for displacing the sample container holding means in order to align successive sample containers with the entrance window of the radiation detector for automatic measurement of samples in the sample containers, the radiation detector and the sample container holding means being movable relative to one another in such a way that the sample container being measured and the entrance window of the detector are disposed coaxially with each other, the improvement wherein said device further comprises:

• a diaphragm plate (10) provided with at least one aperture, said diaphragm plate being fixedly disposed between said aperture, said diaphragm plate being fixedly disposed between said entrance window (31) of said detector (30) and said sample container holding region;
• means for forming a light-tight coupling between a sample container (21) placed underneath said entrance window and said entrance window;
• and
• means disposed for pressing the sample containers against said diaphragm plate (10) with a constant pressure while permitting the sample containers to be displaced parallel to said diaphragm plate by said displacement devices.