Abstract: A device for simultaneously measuring the level of particle and quantum radiation of a plurality of samples which includes a microplate having a plurality of wells for accommodating the plurality of samples. A plurality of light conductors, at least one for each well, is positioned to receive light from each well and forward it to a photodetector. When luminescence is determined, each well has only one conductor associated therewith and when liquid scintillation is determined, each well has two light conductors associated therewith.