Magnetic Pair Spectrometer Studies of Electromagnetic Transitions inC14andN14

Abstract

An intermediate-image pair spectrometer was used to study electromagnetic transitions in ${\mathrm{C}}^{14}$ and ${\mathrm{N}}^{14}$. Energy levels in these nuclei were populated by means of the ${\mathrm{C}}^{13}(d, p){\mathrm{C}}^{14}$ and ${\mathrm{C}}^{13}(d, n){\mathrm{N}}^{14}$ reactions with deuteron energies between 1.9 and 3.1 MeV. In ${\mathrm{C}}^{14}$ a 6.58-MeV transition was observed in the internal pair spectrum but not in the external pair spectrum. From this a definite assignment of $J^{\pi }=0^{+}$ can be made for the ${\mathrm{C}}^{14}$ 6.58-MeV level. In ${\mathrm{N}}^{14}$ the branching ratios of the 5.69→0 and 5.69→2.31 transitions were determined to be 37±2% and 63±2%, respectively. The energy differences between close-lying pair lines were measured with sufficient accuracy to allow limits to be placed on the lifetimes of some states in ${\mathrm{C}}^{14}$ and ${\mathrm{N}}^{14}$. Thus, it was determined that the mean lifetime of the ${\mathrm{C}}^{14}$ 6.58-MeV level is greater than 4×${10}^{-13\mathrm{}}$ sec.