A New Evaluation ofheby X-Rays

Abstract

In previous evaluations of $\frac{h}{e}$ by x-rays the correction for the work function of the cathode has been the principal source of error. New experiments have been performed with a technique which eliminates this error and proves conclusively that in the usual x-ray method a correction for the cathode work function must be made. It is also shown that the separation of the fine structure peaks from the cut off point of the high frequency limit is a function of the voltage applied to the x-ray tube. The value of $\frac{h}{e}$ computed with the new velocity of light is (1.37928\ifmmode\pm\else\textpm\fi{}0.00004) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}17}$ erg sec ${\mathrm{esu}}^{\ensuremath{-}1}$.