Benjamin Donovan
The Pennsylvania State University
In a traditional X-ray spectrometer, there are four optical elements: a two-part Wolter-I (paraboloid-hyperboloid) X-ray telescope, a grating array, and a detector array at the focal plane. Even with the latest X-ray grating technologies, current X-ray grating spectrometers suffer major throughput losses at the grating array due to unavoidable geometric and reflectivity throughput losses. This proposal seeks support to develop a novel, low-TRL X-ray optics technology which could eliminate this throughput loss by combining the secondary (hyperboloid) mirror of the X-ray telescope and the off-plane grating into a single optical element. To develop this technology, we will need to understand the conical grating geometry and how grating features map to the conical surface. In addition, we will need to determine the best interface between current telescope and grating processes so that we can fabricate the gratings onto the conical surface at the optimal time which does not disturb mirror fabrication efforts. And finally, we must develop nanofabrication methods to manufacture the grating features onto the conical surface. If these challenges can be overcome, conical off-plane gratings have the potential to significantly increase the performance of future NASA X-ray spectrometer missions, vastly increasing the amount of science which could be performed.