NEUTRON SPECTRUM OF AN ACTINIUM–BERYLLIUM SOURCE

Abstract
The neutron spectrum of an Ac227-α-Be source has been determined from proton recoil tracks in nuclear emulsions, and found to be in general agreement with the spectra of Po-α-Be and Ra-α-Be sources. Direct observation is limited to neutron energies above about 0.5 Mev. The question of neutrons below this energy is also considered.
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