Multiple-Independent Detector System

The Weapons Neutron Research (WNR) facility has several neutron diffraction and scattering instruments which use arrays of 3He-filled proportional counters to detect thermal and epithermal neutrons and to measure time of flight. A Multiple-Independent Detector System (MIDS) has been developed with emphasis on high speed, low cost, modularity, and simplicity. Dead time for one detector channel is 400 ns, and system throughput may be 6 MHz. Cost is $200 per detector, including amplifiers, multiplexers, and time analysis. Modules include individual shaping preamps for each detector, a 32-channel discriminator/multiplexer, a family of second-level multiplexers incorporating line drivers, an 8-bit optoisolated latch, and a time-of-flight clock which concatenates time and detector information and interfaces through CAMAC to a data-acquisition system. Four systems are now in operation, with 25 to 100 detectors each.