Concept Study Report and Development Effort Proposal for "The Development of X-ray Grating Spectrometers for Future Missions"

The major goal of this proposal is to develop X-ray reflection gratings for future NASA missions. Off-plane reflection gratings are an innovative technology that is capable of providing an efficient means of obtaining high resolution spectra at soft X-ray energies. Reflection gratings are currently employed in the XMM-Newton Reflection Grating Spectrometer (RGS) while the off-plane mount has been used in suborbital rockets, and studied for Explorer class missions such as the Warm-Hot Intergalactic Medium Explorer (WHIMEx) and future X-ray observatories such as the International X-ray Observatory (IXO), the Advanced X-ray Spectroscopic Imaging Observatory (AXSIO), and the Notional X-ray Grating Spectrometer (N-XGS). Future science goals require higher spatial resolution, higher spectral resolution, and higher throughput to perform the key plasma diagnostics. This translates to a spectral resolving power of 3000 (lambda/delta lambda) and effective area of 1000 cm^2 over a 0.3-1.5 keV energy range as appropriate performance requirements. An Off-Plane X-ray Grating Spectrometer (OP-XGS) can reach these goals when coupled with a large area, modest resolution telescope. Several spectrometer designs incorporating a ~5-15" telescope followed by an array of off-plane gratings dispersing light onto a CCD camera have been formulated during observatory program studies. We present here a course of effort designed to contribute toward the development of off-plane gratings technologies including fabrication, replication, alignment, and testing. Over the course of a 9 month Concept Study we have identified a novel fabrication technique that we plan to implement during the four year Development Effort. The result will be a high-fidelity off-plane grating capable of achieving the performance requirements of future X-ray missions. We plan to replicate these gratings, align them into a module mount, and performance test the assembly. This work will leverage heavily off of a current NASA Strategic Astrophysics Technology grant and will be critical to the technology development necessary for a recently awarded NASA suborbital rocket program. More »