Particle analyzer of the coulter type including coincidence error correction circuitry

In a particle analyzer subject to coincidence errors in counting particle pulses, the combination including:

• a first sensing zone arrangement for generating a first train of particle pulses having a first number of particle pulses in response to passage through said sensing zone of a sample containing a plurality of particles to be counted,
• generating means including a second sensing zone arrangement having a particular critical volume which has a known ratio to the critical volume of the first sensing zone arrangement, said second zone arrangement being operative to generate a second train of particle pulses in response to passage of a second sample containing a plurality of particles to be counted through said second sensing zone, said second sample having a volume equal to said first sample, and
• circuit means coupled to said first sensing zone arrangement and said generating means, said circuit means being operative to mathematically change said first and second number of pulses and accumulate said first and second number of pulses in accordance with the equation ##EQU1## for producing an error corrected particle pulse count wherein N.sub.1 is the number of first particle pulses in said first pulse train, N.sub.2 is the number of second particle pulses in the second pulse train, a is the ratio of aperture size or aperture critical volume and N.sub.0 is the error corrected particle pulse count.

In a particular analyzer subject to coincidence errors in counting particle pulses, the combination including:

• a first sensing zone arrangement for generating a first train of particle pulses having a first number of particle pulses in response to passage through said sensing zone of a sample containing a plurality of particles to be counted,
• generating means including delay circuit means coupled to said first sensing zone arrangement and operative in response to said first train of particle pulses, summing means coupled to said delay circuit means and said first sensing zone arrangement for summing said first train of particle and said time delayed first train of particle pulses coupled thereto to develop said second train of particle pulses, and
• circuit means coupled to said first sensing zone arrangement and said generating means, said circuit means being operative to mathematically change said first and second number of pulses and combine said changed first and second number of pulses in accordance with the equation
• N.sub.0 = 2N.sub.1 - (N.sub.2 12)
• for producing an error corrected particle pulse count,
• wherein N.sub.1 is the number of first particle pulses in said first train, N.sub.2 is the number of second particle pulses in the second train and N.sub.0 is the error corrected particle pulse count.

In a particle analyzer subject to coincidence errors in counting particle pulses, the combination including:

• a first sensing zone arrangement for generating a first train of particle pulses having a first number of particle pulses in response to passage through said sensing zone of a sample containing a plurality of particles to be counted,
• generating means for generating a second train of particle pulses having a second number of particle pulses and having a specific relationship to said first train of particle pulses defined by one of the sample volume, sample dilution and sensing zone volume for said first sensing zone arrangement, and
• circuit means coupled to said first sensing zone arrangement and said generating means, said circuit means being operative to mathematically change said first and second number of pulses and combine said changed first and second number of pulses in accordance with the equation
• 2N.sub.1 -(N.sub.2 /2) = N.sub.0
• for producing an error corrected particle pulse count, wherein N.sub.1 is the number of first particle pulses in said first train, N.sub.2 is the number of second particle pulses in the second train and N.sub.0 is the error corrected particle pulse count.

An apparatus for automatically developing an error corrected pulse count in response to first particle pulses which are subject to coincidence error including in combination:

• receiving means for receiving the first particle pulses,
• delay means coupled to said receiving means for delaying the first particle pulses,
• summing means coupled to said delay means and said receiving means for summing the first particle pulses and the delayed first particle pulses to develop second particle pulses,
• circuit means coupled to said summing means and said receiving means for mathematically changing at least one of the number of first pulses and the number of second pulses, and second circuit means coupled to said first circuit means operative to accumulate said number of first and second pulses for producing said error corrected pulse count.