SPECTOMETER FOR FISSION NEUTRONS

Apparatus for measuring the spectra of fission neutrons in the range 0.2 to 7 Mev by the time-of-flight method is described. Time intervals are measured by transforming them into pulse amplitude distributions which are registered in a multichannel analyzer. Time resolution, determined by the half width of gamma - gamma coincidences of /sup 60/Co, is approximates 2 nsec for 100% efficiency and 0.7 nsec for 10% efficiency. Gas scintillation counters, semiconductor detectors, and ionization chambers serve as fission fragment detectors. The half width of time resolution for fission gamma rays of these detectors are 3, 5 to 4, and 10 nsec, respectively. (tr-auth)