The MaGIXS Sub-Grating Diffraction Experiment and its Implications for Instrument Integration and Alignment

Abstract:

The Marshall Grazing Incidence X-Ray Spectrometer (MaGIXS) is a NASA sounding rocket instrument designed to observe Soft X-Ray (SXR) emission lines in the solar atmosphere with high spatial and spectral resolution. This experiment will provide the quantitative data needed to cross-reference current models with theory regarding the widely debated topic of solar coronal heating. The unique optical layout of MaGIXS utilizes a nanoprinted-silicon grating with varied line spacing placed in a converging cone of rays. Highly chirped line spacing makes it possible to achieve high imaging quality (spatial and spectral) with a planar grating at shallow graze angles. The line spacing of the diffraction grating is defined by a third order polynomial and every 372nd line is removed from the line profile, effectively producing a sub-grating optimized for diffraction of the HeNe central wavelength (632.8 nm). This novel design permits the grating to be aligned on an optical bench without the need for X-ray facilities. The sub-grating’s performance is assessed by measuring the far-field diffraction pattern resulting from the illumination of the grating with a collimated HeNe incident beam. We will present the results of this diagnostic experiment, which determine if the grating is suitable for alignment using the current integration and alignment plan for MaGIXS.