Abstract: A method of maintaining measurement accuracy of specific constituents in prompt gamma neutron activation analyzers in a flow of bulk material having a known range of flow rates. The method comprises the steps of providing a plurality of samples of the bulk material for insertion into the analyzer in geometries and quantities referred to as loading profiles. Each of the loading profiles is inserted into the analyzer and measured long enough to yield a measurement uncertainty that is small compared to the observed differences in analysis results from one loading to another. The results are recorded and differences computed as measured errors for subsequent mathematical generation of the expected error at any loading value.

Abstract: A method and apparatus for rejecting signals exhibiting pulse pile-up and devices incorporating the method and/or apparatus. A pulse sensor senses pulses and an analog-to-digital converter digitizes the sensed pulses into discrete ADC values over a plurality of time slices. The digitized pulses are stored in a FIFO memory for processing by a classification processor. The processor qualifies the pulse and marks its first time slice. The processor includes accumulators that calculate parameters from various regions of the pulse. The calculated parameters are compared to criteria from identical regions of known, non-piled pulses. Pulses whose calculated parameters meet the criteria are accepted and stored in one memory location, and pulses whose calculated parameter do not meet the criteria are rejected and stored in another memory location.