Abstract: A method of making a count probe for counting particles comprises the following steps. A count wafer is formed along with a core member having an opening for accepting the count wafer. The count wafer is applied to the opening in the core member to form an interference fit between the count wafer and the core member. After application of the count wafer to the opening in the core member, the core member is annealed to relieve stress in the core member.

Abstract: A method and apparatus for correcting a particle pulse count subject to coincidence error is disclosed wherein particle pulses, developed in response to passage of particles in a particulate system through a sensing zone, are counted for a predetermined period of time. The predetermined period of time is increased or extended in response to each pulse counted by a time increment that is a function of a characteristic of the counted pulse, such as the pulse width, duration, or amplitude. The total additional time period allows the counting of additional particle pulses such that the total count at the end of the extended time period is an error corrected count for the number of particles detected in the predetermined time period.