A Comparison of Several Nuclear Absolute Voltage Determinations

An evaluation of the consistency between the absolute voltage determination of the threshold energy of the ${\mathrm{Li}}^7\mathrm{}(p,n)\mathrm{}{\mathrm{Be}}^7$ reaction as measured by Herb, Snowdon, and Sala and earlier independent absolute alphaparticle energy measurements has been made. The experimental comparison was affected by employing the natural alpha-particles from polonium and radium C′, the energy of which has been measured absolutely by several authors using magnetic deflection methods. In this experiment the alpha-particles from these substances have been electrostatically deflected in the 90° cylindrical electrostatic analyzer at the University of Wisconsin. Alpha-particle line measurements were analyzed by numerical integration of resolution and source functions and in themselves contributed negligibly to the uncertainties of the comparison. The resulting alpha-particle energies, evaluated by comparison with the energy of the ${\mathrm{Li}}^7\mathrm{}(p,n)\mathrm{}{\mathrm{Be}}^7$ threshold, agree with earlier measurements, and indicate that within the limits of accuracy of the experiments, all determinations give identical results.