Magnetic Lens Spectrometer Measurements of the Radiations from Light Nuclear Reactions

Abstract

The radiations from a number of light nuclear reactions are studied with a magnetic lens spectrometer. The $\ensuremath{\gamma}$-ray energies and intensities are determined from the photoelectric and Compton conversion processes; a new method for intensity measurements is developed in which "thick" Compton converters are used. The complicating effects of Doppler shift and broadening on energy determinations are discussed. The following transition energies, obtained from thick targets at bombarding energies from one to two Mev, are reported: ${\mathrm{C}}^{13}(d,n){\mathrm{N}}^{14}$: 725\ifmmode\pm\else\textpm\fi{}4 (assignment uncertain), 1638\ifmmode\pm\else\textpm\fi{}8, 2310\ifmmode\pm\else\textpm\fi{}12, 3381\ifmmode\pm\else\textpm\fi{}13, 5052\ifmmode\pm\else\textpm\fi{}25, and 5690\ifmmode\pm\else\textpm\fi{}50 kev; ${\mathrm{C}}^{13}(d,p){\mathrm{C}}^{14}$: 6110\ifmmode\pm\else\textpm\fi{}30 kev; ${\mathrm{C}}^{12}(d,p){\mathrm{C}}^{13}$: 3082\ifmmode\pm\else\textpm\fi{}7 kev; ${\mathrm{N}}^{15}(p,\ensuremath{\alpha}){\mathrm{C}}^{12}$: 4443\ifmmode\pm\else\textpm\fi{}20 kev; ${\mathrm{B}}^{10}(p,\ensuremath{\alpha}){\mathrm{Be}}^{7}$: 428.5\ifmmode\pm\else\textpm\fi{}1.8 kev; ${\mathrm{Li}}^{6}(d,n){\mathrm{Be}}^{7}$: 428.9\ifmmode\pm\else\textpm\fi{}2 kev; ${\mathrm{Li}}^{6}(d,p){\mathrm{Li}}^{7}$: 477.4\ifmmode\pm\else\textpm\fi{}2 kev; ${\mathrm{O}}^{16}(d,p){\mathrm{O}}^{17}$: 870.5\ifmmode\pm\else\textpm\fi{}2 kev. The internally formed positron distribution from the 3.08-Mev transition in ${\mathrm{C}}^{13}$ is found to be in agreement with the theoretical distribution for an electric dipole transition; the internally formed positron distributions from ${\mathrm{C}}^{13}+d$ and ${\mathrm{Be}}^{9}+d$ are also observed but because of the uncertainty of the background, it is not possible to make unambiguous multipole assignments. The observed internal conversion line spectrum from the 870-kev transition of ${\mathrm{O}}^{17}$ indicates that the transition is electric quadrupole or a mixture of this and magnetic dipole. Semi-empirical formulas are given in the appendix for the most probable and effective energy losses of fast electrons traversing light materials.