Western Kentucky University Department of Physics and Astronomy
Colloquium
Dr. Danielle Gurgew
Goddard Space Flight Center NASA
"Thin Film Coatings for X-ray Optics: Bringing the High-Energy Universe into Focus"
February 26, 2024 @ 4:00 pm in KTH 2038 (Zoom ID: 93595838321)
Abstract
X-ray optics for astronomical imaging utilize a grazing incidence geometry to shallowly reflect photons towards the focal plane. A common prescription, known as Wolter-I, consists of a paraboloid and hyperboloid that, in sequence, enable the collection of X-rays. However, reflecting radiation at graze angles less than 1 degree results in a relatively low collecting area. To improve throughput, X-ray optics are concentrically nested to build up this area and improve sensitivity. Reflection efficiently is further increased by depositing thin film coatings of high-density metals onto the optical surface. X-ray telescopes such as Chandra (NASA) and XMM-Newton (ESA) utilize thin layers of iridium and gold, respectively, to improve throughput in the standard X-ray band of 1 – 10 keV.
However, next-generation hard X-ray telescopes, such as the proposed HEX-P, will require new thin film coating technologies and designs, such as multilayer coatings, to extend imaging capabilities into the 100’s of keV. The X-ray astronomy group at NASA Marshall Space Flight Center is working on advancing optical design, fabrication and alignment/mounting of X-ray optics for use on future flight projects. As an integral part of this larger effort, the thin film coating lab is actively researching novel techniques and coating designs for astronomical telescope applications. Current research efforts concerning coating development as applied to high-angular resolution X-ray optics will be presented.
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