FAST NEUTRON TIME-OF-FLIGHT SPECTROMETER USED WITH KARLSRUHE ISOCHRONOUS CYCLOTRON

A high resolution, fast neutron, time-of-flight spectrometer used for neutron energies between about several hundred kiloelectron volts and 30 MeV is described. A 1 nsec neutron pulse occurring with a repetition rate of 20 kc is obtained with a novel ''bunching deflection'' system operating on the internal beam of the fixed energy Karlsruhe isochronous cyclotron. By the timing of the neutrons over a 57 m flight path a resolution of 0.025 nsec/m at optimum was obtained. Detector counts are accumulated in a 2×8000 channel time analyzer system with 1 nsec channel width. A planned flight path of 180 m and an increase of the repetition rate from 20 kc at present to 200 kc is expected to provide further improvements of the spectrometer. © 1968 The American Institute of Physics.