SE OF A SPATIALLY DISCONTINUOUS PHYSICAL STIMULUS TO IMPROVE DETECTION SENSITIVITY FOR SIGNALS FROM PARTICLES IN A FLOW CHAMBER

摘要

1519312 Analysis of flowing cells G D SEARLE & CO 25 Sept 1975 [26 Sept 1974] 39310/75 Heading G1A Apparatus for distinguishing particles 12 in a fluid comprises a narrow channel 14 and means for maintaining a certain flow, means for applying a stimulus at separate positions along the channel to elicit separate responses, which collectively comprise a coded response, transducer means 17 for converting the separate responses to signals, and means correlated with the flow-rate and the position spacing to decode and combine the signals to a single signal. An arc lamp or laser 1 with condenser lens 2 uniformly illuminates coding mask 3 producing beams B1 to B7 imaged by lens 4 in channel 14 of capillary tube 13, in which cells 12 flow in single file. Fluorescent output from each cell is imaged on photo-multiplier 17, with filter 16 blocking the exciting wavelengths or alternatively photomultiplier 17 being perpendicular to the exitation. The distance between B 1 & B2 is (#2 - #1) x the spacing factor, and (#3 - #2) x the spacing factor for B 2 and B 3 and so on. The delays of delay line 19 correspond to these spacings, so that the pulses due to beams B 1 -B 7 reach adder 20 simultaneously Processor 28 classifies the number of output signals within certain amplitude ranges. These are tabulated in registers 29, 30, 31. In the embodiment of Fig. 5 (not shown) amplifier 18 is followed by filter (32) blocking the high frequency noise and passing the low frequency signal pulses to integrator (33) feeding processor 28. Multiple responses from the transducers may be produced by exiting the cells concurrently or successively with a plurality of wavelengths.