Recent developments in multiplicity counting hardware at Los Alamos

A prototype, 256-channel neutron-multiplicity-counting circuit is described. It is being used with a 4-MHz shift-register-based neutron coincidence circuit. The circuits mount in a double-wide nuclear instrument module. The goal in this project was to provide hardware for investigating the feasibility and limitations of multiplicity counting with standard counters and hardware. The goal was to have real-time processing of multiplicity from the shift register implemented simply, in minimal size, and at relatively low power. The engineering problem was to take the multiplicity information and record the multiplicity distribution information at an average rate of 2.3×10⁶ events/s. Initial circuit performance tests are reported