Neutrons FromC12+D

Abstract

Recoil protons in a cloud chamber have been used to measure the energy spectrum of the neutrons from ${\mathrm{C}}^{12}$+${\mathrm{H}}^2$. The neutrons are found to be monochromatic when produced by 2-Mev deuterons. An accurate $Q$ value of -0.27±0.02 Mev is computed from the range of the recoil protons. This $Q$ value gives a mass of 13.00988±0.00004 for ${\mathrm{N}}^{13}$.