Nitrogen 12

${\mathrm{N}}^{12}$ is shown to have a half-life of 12.5±1 milliseconds, and a positron upper limit of 16.6±0.2 Mev. It is produced by the reaction ${\mathrm{C}}^{12}\mathrm{}(p,n)\mathrm{}{\mathrm{N}}^{12}$, and has a threshold proton energy of 20.0 Mev. This indicates that ${\mathrm{N}}^{12}$ is within about 200 kev of being unstable against proton emission. The mass of ${\mathrm{N}}^{12}$ is 12.0228±0.00015, and the beta-transition is allowed.