Visible light emitting from a helium plasma source (not visible in photo) reflects off a sample of indium tin oxide (ITO) on glass inside an ultra-high vacuum chamber. Invisible ultraviolet light from the same helium source excites electrons off of the surface of the sample. Electrons enter the cone above the sample and travel to an analyzer in a technique called ultraviolet photoelectron spectroscopy (UPS). Also shown are an x-ray source (copper barrel on left), an electron gun (cylinder at bottom of photo), and a photon detector (cylinder at bottom right) used with other spectroscopic techniques. Combined, these can give a detailed picture of the chemical and electronic properties at a material surface. ITO is a transparent conductive oxide and an important component of phones, tablets, and displays everywhere. This sample was measured with all of the equipment shown, for comparison of its chemical and electronic properties to those of other metal oxides.