A Cloud-Chamber Study of the Disintegration of Lithium by Slow Neutrons

Abstract

The ranges of tritons and alpha-particles formed in the slow neutron reaction ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(n,\alpha ){}_{}{}^3{}_{}{}^{}\mathrm{H}$ have been measured in a cloud chamber and found to be $R_{\alpha }=10.4\mathrm{}\pm 0.2$ mm and $R_{{}_{}{}^3{}_{}{}^{}\mathrm{H}}=60.0\mathrm{}\pm 0.6$ mm in air at N.T.P.; the corresponding $Q$ values, derived from the blue-printed Cornell energy vs. range curves, disagree, and the $Q$ derived by the proton relation is also in disaccordance with other data. The discrepancies suggest the establishment of a new point on the proton energy vs. range curve, viz., $R_p=20.0\mathrm{}$ mm, $E_p=0.88\mathrm{}$ Mev, which means a reduction of the energy by about 6 percent.