Year
2013
Abstract
Due to the shortage of Helium-3, research has been directed towards the development of alternative technologies capable of reliable and efficient neutron detection. Liquid organic scintillators are being investigated as a possible replacement because of their ability to both detect fast neutrons and reject gamma rays in a mixed field of radiation through the use of pulse shape discrimination. Previous research by other investigators has paired CAEN and Struck waveform digitizers with a variety of liquid organic scintillators to perform digital pulse shape discrimination and time-of-flight experiments. We used the recently developed, 12- bit, 500 mega-sample-per-second (MS/s) XIA Pixie-500 with two EJ-309 liquid organic scintillators to perform bench-top 252Cf time-of-flight experiments and investigate alternative methods of digital pulse shape discrimination. The results of the time-of-flight experiment are presented. The three digital pulse shape discrimination methods that were applied include the standard charge integration technique and two alternative methods (based on pattern-recognition and curve fitting) previously investigated by D. Takaku, T. Oishi, and M. Baba. We found the pattern-recognition method achieved the best neutron-gamma discrimination using a quantitative comparison of separation that estimates the neutron/gamma misclassification rate by fitting overlapping Gaussian distributions to the pulse shape parameter distribution. Due to its relative simplicity, the pattern-recognition algorithm could potentially be implemented on a field-programmable gate array (FPGA) enabling real-time neutron-gamma discrimination with low misclassification rates.