![](\"http:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2016\/12\/silicon_pore_optics_stacks\/16583598-1-eng-GB\/Silicon_pore_optics_stacks_small.jpg\")
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\nStacks of carefully polished, coated and cut silicon wafers \u2013 normally used to manufacture integrated circuits \u2013 that will focus X-rays inside ESA\u2019s Athena space observatory<\/a>, due for launch in 2028.\n<\/p>\n \nInvisible X-rays tell us about the very hot matter in the Universe \u2013 black holes, supernovas and superheated gas clouds. But energetic X-rays do not behave like typical light waves \u2013 try to reflect them with a standard mirror and they are absorbed. Instead, X-rays can only be reflected at shallow angles, like stones skimming across water.\n<\/p>\n \nThat means multiple mirrors must be stacked together to build a telescope. ESA has developed \u2018silicon pore optics\u2019 to see much further into space than the ageing XMM-Newton X-ray observatory<\/a>.\n<\/p>\n \nThis approach is based on industrial silicon wafers, taking advantage of their stiffness and super-polished surface. Grooves are cut into the wafers to form pores through which the X-rays are focused. A few dozen at a time are stacked together to form a single mirror module. Many hundreds of these modules will be combined to form the optics of the X-ray mission.\n<\/p>\n \nTo find out more, check our video interview with ESA optics engineer Eric Wille<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" \nStacks of carefully polished, coated and cut silicon wafers – normally used to manufacture integrated circuits – that will focus X-rays inside ESA’s Athena space observatory<\/a>, due for launch in 2028.\n<\/p>\n \nInvisible X-rays tell us about the very hot matter in the Universe – black holes, supernovas and superheated gas clouds. But energetic X-rays do not behave like typical light waves – try to reflect them with a standard mirror and they are absorbed. Instead, X-rays can only be reflected at shallow angles, like stones skimming across water.\n<\/p>\n \nThat means multiple mirrors must be stacked together to build a telescope. ESA has developed ‘silicon pore optics’ to see much further into space than the ageing XMM-Newton X-ray observatory<\/a>.\n<\/p>\n \nThis approach is based on industrial silicon wafers, taking advantage of their stiffness and super-polished surface. Grooves are cut into the wafers to form pores through which the X-rays are focused. A few dozen at a time are stacked together to form a single mirror module. Many hundreds of these modules will be combined to form the optics of the X-ray mission.\n<\/p>\n<\/p>\n