The original data for precise determinations of the ${}^{10}\mathrm{B}{\mathrm{}(p,n)\mathrm{}}^{10}\mathrm{C}$ and ${}^{14}\mathrm{N}{\mathrm{}(p,n)\mathrm{}}^{14}\mathrm{O}$ threshold energies have been reanalyzed to fully incorporate the effects of proton beam energy spread, nonuniform proton energy loss in the targets, and atomic ionization. The results have been used to give Q values for the $0^{+}$ to $0^{+},$ $T=1\mathrm{}$ superallowed positron decays of ${}^{10}\mathrm{C}$ and ${}^{14}\mathrm{O}.$

• Received 7 May 1998

DOI:https://doi.org/10.1103/PhysRevC.58.2571