X-ray MirrorsXMM-Newton uses an unusual technique to focus the X-rays onto the different detectors. A "normal" telescope works by reflecting and focusing light. However, X-rays have such high energy that they pass through most materials, making reflection impossible. Instead, for an X-ray telescope, the mirrors are arranged so that the incoming X-rays graze off of the mirrors, like a stone skipping on water. The shape and highly-polished surfaces of the mirrors ensure that the incoming X-rays are focused into a beam when they enter the detectors, just like a "normal" telescope makes a beam of light entering your eye.There are actually three complete sets of X-ray telescopes on-board the satellite, each of which consists of 58 wafer-thin nickel mirrors. The mirrors are gold-plated and nested in each other just a few millimeters apart. XMM-Newton's nested mirror design made it possible to have the largest collecting area of focusing optics deployed for X-ray astronomy. The total mirror surface area exceeds 120 square meters, larger than a tennis court. No previous X-ray satellite could focus even approximately as much radiation as XMM-Newton.
If you have any questions concerning XMM-Newton send e-mail to xmmhelp@athena.gsfc.nasa.gov.
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