Feedback Threshold Control Extends Pulse Rate Measurements into the Pileup Region

By using feedback control of the discrimination threshold we have added 4-6 decades to the useful range of otherwise conventional pulse counting systems. The additional range is obtained at the high end by retarding saturation of the output count rate with higher threshold levels. We have implemented the method with low-power microcircuits that provide a 9-decade range (10-5 to 104 R/h) without the need for range or mode switching.