Intensity Variation ofLSeries X-Ray Lines with Tube Voltage

The variation of intensity of the $L$ series x-radiation, from a copper target, with the voltage applied to the x-ray tube has been studied. The voltage range over which this investigation was made included the $K$ excitation value for copper. A definite increase was found in the slope of the intensity-applied voltage curve, which appeared immediately after the $K$ state was excited. The intensity was plotted against the square of the voltage difference between the $K$ excitation and the applied voltages, and the resulting curve was found to be substantially a straight line. This result is in accord with the theoretical predictions of Smekal and is an improvement over the experimental work of Stumpen.