INSTRUMENTATION FOR FISSION FRAGMENT ENERGY CORRELATION EXPERIMENTS

From International Conference on Nuclear Physics with Reactor Neutrons, Argonne, Ill., Oct. 1963. Experiments were performed in which the kinetic energies of correlated fragment pairs from thermal- and resonance-neutron-induced fission were measured. In addition, a three-parameter ternary fission experiment was performed in which the energies of correlated fragments were measured in coincidence with the energy of a third emitted particle, usually a long-range alpha particle. The detectors were large-area silicon surface barrier detectors. The instrumentation associated with these experiments is discussed in detail. The complete system is described, with attention given to the problems of background reduction (fast-coincidence requirements), stability, linearity, and resolution. Particular attention is given to the reduction of spectrum distortion by pile-up pulses (alphaon-fission pile-up within the amplifier resolving time). Methods and limitations of pile-up detection are discussed. A new method for inspection and removal of pile-up pulses is described. (auth