NEUTRON SPECTRUM OF A Ra–Be(α, n) SOURCE

Abstract

The neutron energy spectrum of a Ra–Be source has been measured successfully by the nuclear emulsion technique without introducing a significant thickness of lead absorber to reduce the γ-ray background. In comparison with the spectra published by other authors, the part of the spectrum below 4 Mev is found to be somewhat less intense, probably owing to the absence of inelastic scattering in the lead. No observations could be made below 0.75 Mev; however, by comparison with the source emission rate, it was estimated that this fraction of the spectrum contributes (37 ± 15)% of the total neutron emission.