A new method is described for measuring the wavelength of peak intensity of x-ray tubes. This method employs known absorption data and gives an independent check on crystal spectrometer measurements. For a tungsten target tube, the measured values were: 50.0 kv spectrum peak at 0.337 A, 45.5 kv at 0.367 A, 39.8, kv at 0.416 A, and 33.5 kv at 0.478 A.
An important companion result is the variation of intensity with tube potential, at constant wavelengths shorter than the peak wavelengths, for spectra corresponding to tube potentials between 30 and 70 kv.
ALAN D. K. LAIRD, "Measurement of the Wavelengths of Maximum Intensity for X-Ray Tube Spectra," J. Opt. Soc. Am. 45, 568-569 (1955)