A system , comprising: an input channel having a first end and a second end to receive particles through the first end; a sensor to categorize particles in the input channel into one of at least two categories; at least two output channels , each output channel fluidically coupled to the second end of the input channel to receive particles from the input channel , each output channel being associated with at least one category of the at least two categories, each output channel having a corresponding pump operable, based on the categorization of a detected particle in a category associated with a different output channel , to selectively slow, stop, or reverse a flow of particles into the output channel from the input channel , an output channel sensor provided in at least one of the at least two output channels ; and a controller coupled to the sensor , to each pump and to the output channel sensor , wherein the controller is configured to: receive a signal from the sensor indicative of categorization of a particle in a selected category of the at least two categories; and selectively actuate each pump corresponding to an output channel that is associated with a different category than the selected category, wherein the controller is configured to wait for a signal from the output channel sensor that the previous sorted particle has reached a predetermined point within the at least one output channel. an input channel having a first end and a second end to receive particles through the first end; a sensor to categorize particles in the input channel into one of at least two categories; at least two output channels , each output channel fluidically coupled to the second end of the input channel to receive particles from the input channel , each output channel being associated with at least one category of the at least two categories, each output channel having a corresponding pump operable, based on the categorization of a detected particle in a category associated with a different output channel , to selectively slow, stop, or reverse a flow of particles into the output channel from the input channel , an output channel sensor provided in at least one of the at least two output channels ; and a controller coupled to the sensor , to each pump and to the output channel sensor , wherein the controller is configured to: receive a signal from the sensor indicative of categorization of a particle in a selected category of the at least two categories; and selectively actuate each pump corresponding to an output channel that is associated with a different category than the selected category, wherein the controller is configured to wait for a signal from the output channel sensor that the previous sorted particle has reached a predetermined point within the at least one output channel. receive a signal from the sensor indicative of categorization of a particle in a selected category of the at least two categories; and selectively actuate each pump corresponding to an output channel that is associated with a different category than the selected category, wherein the controller is configured to wait for a signal from the output channel sensor that the previous sorted particle has reached a predetermined point within the at least one output channel. <EOS>