Abstract
IN recent years several determinations of h/e from the short wave-length limit of the continuous X-ray spectrum have been made. The results obtained from this method, however, disagree definitely with the value of h measured by other methods. According to Kirchner1 the most accurate determinations of h/e by the method of isochromats give h = 6·614 × 10-27 erg sec., provided e = 4·803 × 10-10 E.S.U., e/m = 1·759 × 107 E.M.U./gm. and R∞ = 109·737 cm.-1. This discrepancy has not yet been explained. Also the shape of the isochromats, especially in the vicinity of the short wave-length limit, causes a problem. Instead of running straight down to zero, thus giving a sharp radiation limit, the isochromats run asymptotically down to zero. This 'foot' of the curve indicates that some electrons hit the anticathode with a velocity which is greater than that corresponding to the voltage applied on the X-ray tube. Various hypotheses have been put forward to account for the existence of such electrons.
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Kirchner, F., Ergebn. exakt. Naturwiss., 18, 26 (1939).
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OHLIN, P. Determination of h/e by the Method of Isochromats. Nature 145, 223 (1940). https://doi.org/10.1038/145223b0
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DOI: https://doi.org/10.1038/145223b0
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