Short Wave-length Limit of the Continuous X-Ray Spectrum and Determinations of h/e

Abstract

As is known, there exists a discrepancy between earlier determinations of h/e obtained from the short wave-length limit of the continuous X-ray spectrum and the value of h/e calculated from Bohr's formula for the Rydberg constant. Thus most of the determinations of h/e by the X-ray method have given values that are 0.3–0.4 per cent lower than the value calculated. This difference is several times greater than the stated limits of error, indicating the presence of systematic errors in the measurements. An error of this nature, due to too high a pressure in the X-ray tube, has previously been pointed out by me1. This error can amount to 0.1–0.15 per cent and is therefore too small to account for the whole of the discrepancy. Further, a number of determinations of h/e have been carried out by means of technical X-ray tubes in which the pressure was sufficiently low.