After UV come X-rays, which, like the upper ranges of UV are also ionizing. However, due to their higher energies, X-rays can also interact with matter by means of the Compton effect. Hard X-rays have shorter wavelengths than soft X-rays and as they can pass through many substances with little absorption, they can be used to 'see through' objects with 'thicknesses' less than that equivalent to a few meters of water. One notable use is diagnostic X-ray imaging in medicine (a process known as radiography). X-rays are useful as probes in high-energy physics. In astronomy, the accretion disks around neutron stars and black holes emit X-rays, enabling studies of these phenomena. X-rays are also emitted by stellar corona and are strongly emitted by some types of nebulae. However, X-ray telescopes must be placed outside the Earth's atmosphere to see astronomical X-rays, since the great depth of the atmosphere of Earth is opaque to X-rays (with areal density of 1000 g/cm2), equivalent to 10 meters thickness of water.Koontz, Steve (26 June 2012) Designing Spacecraft and Mission Operations Plans to Meet Flight Crew Radiation Dose . NASA/MIT Workshop. See pages I-7 (atmosphere) and I-23 (for water). This is an amount sufficient to block almost all astronomical X-rays (and also astronomical gamma rays—see below).
after uv come x-rays which like the upper ranges of uv are also ionizing however due to their higher energies x-rays can also interact with matter by means of the compton effect hard x-rays have shorter wavelengths than soft x-rays and as they can pass through many substances with little absorption they can be used to 'see through' objects with 'thicknesses' less than that equivalent to a few meters of water one notable use is diagnostic x-ray imaging in medicine (a process known as radiography) x-rays are useful as probes in high-energy physics in astronomy the accretion disks around neutron stars and black holes emit x-rays enabling studies of these phenomena x-rays are also emitted by stellar corona and are strongly emitted by some types of nebulae however x-ray telescopes must be placed outside the earth's atmosphere to see astronomical x-rays since the great depth of the atmosphere of earth is opaque to x-rays (with areal density of 1000 g/cm2) equivalent to 10 meters thickness of waterkoontz steve (26 june 2012) designing spacecraft and mission operations plans to meet flight crew radiation dose  nasa/mit workshop see pages i-7 (atmosphere) and i-23 (for water) this is an amount sufficient to block almost all astronomical x-rays (and also astronomical gamma rays—see below)