Design and properties of low energy x-ray transmission windows based on graphenic carbon

TL;DR

This paper presents the design, fabrication, and testing of low-energy x-ray transmission windows made from graphenic carbon, demonstrating high mechanical resilience and improved optical and vacuum properties for advanced detector applications.

Contribution

It introduces a novel graphenic carbon-based window design with a bar grid support structure, showing enhanced performance and durability over traditional polymer-based windows.

Findings

Graphenic carbon windows withstand over 10 million pressure cycles without damage.

Young's modulus of graphenic carbon is approximately 130 GPa.

Finite-element and Raman analyses reveal non-uniform stress distribution near anchoring points.

Abstract

X-ray transmission windows for the low energy range, especially between 0.1 keV 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 allows to substitute polymer-based windows with the advantages of higher transmission, better rejection of visible light and vacuum operability of the encapsulated silicon drift detectors (SDD). In addition, 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.