Flow cytometer apparatus and method

A flow cytometry apparatus comprising:

• a flow channel for directing a fluid stream containing sample particles through a particle interrogation location;
• a laser operable to emit a plurality of electromagnetic radiation pulses, each pulse having a peak power that exceeds the average power of the laser, said pulses being directed along a beam path from the laser to the particle interrogation location;
• a timing circuit operable to produce a timing signal indicative of the of arrival of pulses at the interrogation location;
• a detector adapted to detect electromagnetic radiation from the interrogation location and operable to output a time-varying analog signal indicative the intensity of the detected electromagnetic radiation;
• an analog to digital converter adapted to receive the time-varying analog signal as input and to sample the analog signal to produce a digitized output;
• and
• an electronic processor operable to analyze the digitized output from the analog to digital converter as a function of the timing signal.

A method of analyzing particles contained in a fluid stream as they flow through an interrogation location, said method comprising the steps of:

• emitting a plurality of electromagnetic radiation pulses from a laser, wherein the peak power of each pulse exceeds the average power of the laser;
• intermittently illuminating the fluid stream and the particles contained therein by directing said pulses along a beam path from the laser to the interrogation location;
• detecting electromagnetic radiation from the interrogation location;
• generating a time-varying analog signal indicative of the intensity of the detected electromagnetic radiation;
• generating a timing signal indicative of the arrival of a pulse at the interrogation location;
• converting the time-varying analog signal into a digital signal;
• and
• analyzing the digital signal to determine characteristics of the particles in the fluid stream.