Abstract: A gamma activity counter apparatus for use in automated radioimmunoassay systems including a scintillator counter which has two scintillator crystal-photomultiplier tube assemblies removably contained within a lead radiation shield. Each crystal has formed in it a sample receiving zone, each zone communicating with vertical bores formed in the radiation shield, so that a lifting means can lift sample carriers disposed beneath and in alignment with the sample receiving zones into the zones for gamma activity counting. The lift means is so designed that for each counting period, a pair of sample carriers, separated from each other by an even number of sample carrier spaces, is lifted into the sample receiving zones for simultaneous counting, the sample carriers being contained in holders that are continually advanced over the lift means in increments of two sample carrier spaces per increment.

Abstract: The invention is concerned with a novel container for receiving a liquid material having a fitting at one end adapted to provide a discharge port for the liquid within the container and having at its other end a plunger or piston adapted to be moved within the inside wall of the container to discharge one or more predetermined "aliquots" or "doses" of liquid from the container through the port. The invention also comprises a novel device adapted to receive a liquid-containing cartridge or package of the type just mentioned and having means for coacting with the package to move the plunger within the container during dose-dispensing or -discharge in such a manner as to gradually accelerate movement of the plunger from a position of rest within the container through a maximum rate of motion and then gradually decelerate the motion of the plunger to a final position at the end of the dose-discharge.