Development of blocking filters using high throughput SiC grids

Filter stacks in microcalorimeters (such as those being designed for the Athena X-IFU) must protect the detector from photon shot noise and thermal radiation, while being transparent to X-rays, being able to survive the mechanical loads from launch vibrations, survive a differential pressure during pumping, and be able to be maintained at a constant temperature with a small power draw. This research looks at the benefits of using SiC for the grid material compared to the steel/Au or silicon grids that are more traditionally used. Due to its material properties, SiC offers lower membrane stress and improved thermal conductance than the steel/Au counterpart allowing for smaller power draw to maintain filter temperature for contamination control. SiC also offers an increase in strength compared to Si grids with the SiC grids having been shown to be 5 times stronger over small apertures (10 mm). In the study, SiC grids have been developed, burst tested with a differential pressure, and vibration tested with vibration loads up to the NASA GEVS Qualification standard of 14.1 g rms. Optical inspection of the grids before and after vibration is used to show if the meshes can withstand standard launch vibration loads.