Neutron-Induced Charged Particle Reactions in Potassium-39

Abstract

Thin thallium-activated potassium iodide crystals were exposed to monoenergetic neutrons ranging in energy from 2.0 to 5.5 Mev. Pulse-height spectra were taken of the scintillations in the crystal. Five charged particle groups were observed, three ($n, p$) reactions leading to states in ${\mathrm{A}}^{39}$, and two ($n, \ensuremath{\alpha}$) reactions leading to states in ${\mathrm{Cl}}^{36}$. A new level was discovered at 2.46\ifmmode\pm\else\textpm\fi{}0.1 Mev in ${\mathrm{A}}^{39}$, and the level at about 1.25 Mev in ${\mathrm{A}}^{39}$ confirmed. Yield curves were measured for three of the groups.