Design of Mixed-mode Systems for Pulse-shape Discrimination

The use of a mixed-mode system for performing neutron/gamma (n/γ) pulse-shape discrimination (PSD) is investigated. Historically, PSD capable systems have been composed fully of analog electronics or use fast digitizers that allow for later analysis using digital signal processing (DSP). Analog systems are inexpensive and suitable for large detectors where hundreds, or even thousands, of detector channels are needed. However analog systems are algorithm locked. DSP-based systems allow for more complex algorithms to be used for pulse processing. If fast digitzers are required, DSP systems can be prohibitively expensive for large channel-count detectors. A topology is proposed for a PSD capable mixed-mode system that combines analog and DSP techniques. The topology is modeled in Verilog-A and analyzed using waveform data from several scintillators to show that mixed-mode systems are PSD capable and offer advantages over pure analog or DSP systems.