Abstract: A system for characterizing objects to be sorted in real time and making sorting decisions using lasers to excite fluorescing dyes used to tag objects such as cells which flow through the laser beam in a stream of conductive fluid. The scattered light and fluorescent light at various frequencies define a multidimensional space. These light characteristics are sensed and digitized. The data so gathered is buffered and then compared to a binary classification tree. The individual parameters cause a certain path through the binary decision tree to be taken while the cell is passing from the point in the stream where the light characteristics are gathered to a point where electrostatically charged electrodes deflect individual statically charged drops containing cells to be sorted into various sorting bins. When the decision tree has been traversed, the sorting decision for the drop containing the cell which had those parameters is done.

Abstract: Method and apparatus for sorting individual particles into containers, such as the wells of a microculture tray, are disclosed. The particles may comprise, for example, individual biological cells which then may be cultured, cloned, analyzed, or the like. The particles are incorporated into a flow stream which is jetted from a nozzle which is vibrated in the direction of the stream to break the jet stream into discrete drops. A particle sensor senses particles in the stream, and a signal processor in response to the particle sensor output produces an output when the sensed particle is of the type to be sorted from the stream. A pulse charger, responsive to the signal processor, is included for charging the drops as they break from the vibrating jet stream. The drops pass between charged deflection plates where they are deflected an amount related to the drop charge. For individual cell sorting, the signal processor is in normal inopertive condition to prevent sorting of drops from the drop stream.

Abstract: Method and apparatus for semi-automatic feeding of liquid samples from a plurality of sample sources to a scanning device are disclosed. The liquid samples are picked up from a preidentified sample source and delivered to the scanning device by use of a hand-held pick-up and delivery tube. The hand-held tube is releasably coupled to the scanning device for delivery of the liquid samples to the scanning device when coupled thereto. In the disconnected condition, particle free fluid flows in a reverse direction from the scanning device for automatic flushing of the scanning device and liquid sample supply line connected thereto. Visual display means for visually indicating to the operator which sample holder the next sample is to be obtained from is provided.