Method for the determination of the neutron multiplicity counter dead time parameter

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#Not Applicable

#The present invention will be more fully understood by reference to the following detailed description of the preferred embodiments of the present invention when read in conjunction with the accompanying drawings, in which like reference numbers refer to like parts throughout the views, wherein:

#FIG. 1 is a plot of the non dead-time Triples to Doubles ratio as a function of count rate for a series of 252Cf point sources from a Plutonium Scrap Multiplicity Counter. The slope of the linear fit to the data is equal to 4 times the multiplicity dead-time parameter, τ for this counter (slope/4=(106.9+/−1.0) ns compared to the measured dead time parameter of 105.3 ns). For comparison, the expected exponential curve is shown;

#FIG. 2 is a plot of the slope of the Triples to Doubles curves divided by the observed characteristic counter dead-time as a function of neutron detection efficiency for a series of 32 diverse neutron counters;

#All figures are drawn for ease of explanation of the basic teachings of the present invention only; the extensions of the figures with respect to number, position, relationship, and dimensions of the parts to form the preferred embodiment will be explained or will be within the skill of the art after the following teachings of the present invention have been read and understood. Further, the exact dimensions and dimensional proportions to conform to specific force, weight, strength, and similar requirements will likewise be within the skill of the art after the following teachings of the present invention have been read and understood.

#Examination of non-dead-time corrected rates is helpful in dead-time calibrations. A plot of the ratio of the non dead-time corrected Triples rates, Tm, to Doubles rate, Dm, yields a linear function of the non dead-time corrected Singles rate, Sm. The preferred embodiment of the present invention utilizes this linear fit in subsequent dead-time calibrations.

#In Dytlewski's approach, the Singles or Trigger rate is corrected empirically while a special formalism is required for the Doubles and Triples. Hybrid solutions suggest themselves where the traditional approaches are used for the Singles and Doubles wherever needed with only the histogram based treatment being applied to the Triples term. This last approach avoids discrepancy between standard neutron coincidence counter (NCC) and multiplicity results but introduces some complications in the propagation of rates errors.