Axial trajectory sensor having gating means controlled by pulse duration measuring for electronic particle study apparatus and method

Claim 1

An axial trajectory sensor for use with a Coulter type particle analyzing apparatus in which particles passing through an aperture generate desirable particle pulses whose amplitudes are most nearly proportional to their respective sizes when passing closest to an axial trajectory through the aperture and having thereby a certain approximate shape and in which particles passing through said aperture on trajectories displaced from the axis will generate undesirable particle pulses whose amplitudes are not necessarily proportional to their respective sizes and whose shapes tend to depart from said certain approximate shape; said sensor acting to respond to desirable pulses and not to respond to said undesirable particle pulses and comprising: A. input terminal means and output terminal means having a channel for passage of electrical signals between the terminal means with switch means in said channel to control the signals which appear at the output terminal means, the input terminal means adapted to have the desirable and undesirable particle pulses applied thereto, B. means for measuring the duration of at least a segment of a particle pulse applied to said input terminal means at a plurality of different predetermined fractions of the amplitude thereof and deriving a plurality of duration-measuring pulses having the measured durations of the pulse segments at the respecTive fractions, C. means for converting each said duration-measuring pulse into a respective electrical time signal pulse whose amplitude is proportional to the duration of the duration-measuring pulse from which it has been converted whereby to derive a plurality of electrical time signal pulses, D. means connected with said converting means acting to establish for at least less than all of said electrical time signal pulses individual to said respective fractions a voltage level for each said electrical time signal pulse, each electrical time signal pulse derived from a desirable particle pulse falling below its so-established voltage level and if derived from an undesirable particle pulse falling above its so-established level, E. means comparing the amplitude of each said electrical time signal pulse individual to said respective fractions with its so-established voltage level and producing one type of energized signal if said last-mentioned electrical time signal pulse is less than its so-established voltage level and producing a second type of energizing signal if said lastmentioned electrical time signal pulse is greater than its soestablished voltage level, F. means for producing a strobing pulse of predetermined duration for each particle pulse applied to said input terminal means, and G. gating means having said strobing pulse applied thereto, every energizing pulse produced by said comparing means also being applied to said gating means, said gating means being connected to said switch means in the channel and acting to operate said switch means to pass a signal derived from said input terminal means when said strobing pulse is applied, but only if every energizing signal is of the first type.

Claim 29

The method of sensing between the particle pulses caused by particles passing through a Coulter particle apparatus aperture on the axis of the aperture and off the axis of the aperture, which comprises: A. measuring the duration of each particle pulse at a plurality of predetermined fractions of the amplitude thereof and deriving therefrom a plurality of duration-measuring pulses of constant amplitude and each having a respective duration, B. converting the duration-measuring pulses into respective electrical time signal pulses whose amplitudes are respectively proportional to the time durations of the said duration-measuring pulses, C. establishing for at least less than all of said fractional amplitudes a signal level for each, equivalent to the maximum desired duration for each time signal pulse individual to each said fractional amplitude having a signal level, D. comparing the said electrical time signal pulses having signal levels each with its particular signal level and obtaining an energizing signal of one type for each electrical time signal pulse that does not exceed said level and an energizing signal of a second type if said level is exceeded, there being one such energizing signal for each electrical time signal pulse having a signal level, and E. deriving an electrical signal from each whole particle pulse and passing or blocking the derived signal on the basis of whether all of the energizing signals are of the first type or any of the signals is of the second type, respectively.

Claim 30

The method of sensing between the particle pulses caused by particles passing through a Coulter particle apparatus aperture on the axis of the aperture and off the axis of the aperture, which comprises: A. measuring the duration of each particle pulse at a plurality of predetermined fractions of the amplitude thereof and deriving therefrom a plurality of duration-measuring pulses of constant amplitude and each having a respective duration, B. converting the duration-measuring pulses into respective electrical time signal pulses whose amplitudes are respectively proportional to the time durations of the said duration-measuring pulses, C. establishing for at least less than all of said fractional amplitudes a signal level for each, equivalent to the maximum desired duration for each time signal pulse individual to each said fractional amplitude having a signal level, D. comparing the said electrical time signal pulses having signal levels each with its particular signal level and obtaining an energizing signal of one type for each electrical time signal pulse that does not exceed said level and an energizing signal of a second type if said level is exceeded, there being one such energizing signal for each electrical time signal pulse having a signal level, and E. deriving an electrical signal from each whole particle pulse and passing or blocking the derived signal on the basis of whether all of the energizing signals are of the first type or any of the signals is of the second type, respectively.