X-ray diffraction

X-rays were discovered by German Physicist W.C. Röntgen in 1895. X-rays are electromagnetic radiation having a much shorter wavelength than visible light and there for are more energetic. Using this additional energy of these “soft” x-rays we can probe the inter-atomic distance in crystalline materials at a depth of 1-10’s of microns into the surface. Assuming a planar stress state and using the inter-atomic spacing as the ultimate gage length allows us to measure absolute stress without the need for unstressed samples for calibration.