Design and properties of low‐energy X‐ray transmission windows based on graphenic carbon

X-ray transmission windows for the low energy range, especially between 0.1 and 1 keV have been designed and fabricated based on graphenic carbon (GC) with an integrated silicon frame. A hexagonal and a bar grid support structure design have been evaluated. The bar grid design offers higher X-ray transmission and better visible light rejection than polymer-based windows, and allows vacuum encapsulation of silicon drift detectors (SDD). The high mechanical resilience of graphenic carbon is demonstrated by pressure cycle tests, yielding over 10 million cycles without damage. The data are complemented by bulge tests to determine a Young's modulus for graphenic carbon of approximately 130 GPa. Additional finite-element simulation and Raman studies reveal that the mechanical stress is not homogeneously distributed, but reaches a maximum near the anchoring points of the free standing graphenic carbon membrane