Nevis Synchrocyclotron Slow Neutron Velocity Spectrometer

A high-intensity, high-resolution neutron velocity selector system, employing the Nevis synchrocyclotron as a source of pulsed neutrons, is described. Detector counts are accumulated in a 2000-channel analyzer with 0.1-μsec channel width. Punch card data reduction techniques are discussed. Resonance spectra of PbI2 obtained using a 35-m flight path provide an example of the resolution and illustrate the use of the self-indication capture γ-ray detector scheme extensively employed. A planned flight path of 200 m is expected to provide a resolution of <1 nsec/m for neutron energies above 1000 ev.