Protective radiolucent aluminium oxide coatings for beryllium X-ray optics

Abstract

Beryllium, being one of the most transparent materials to X-ray radiation, has become the material of choice for X-ray optics instrumentation at synchrotron radiation sources and free-electron laser facilities. However, there are concerns due to its high toxicity and, consequently, there is a need for special safety regulations. The authors propose to apply protective coatings in order to seal off beryllium from the ambient atmosphere, thus preventing degradation processes providing additional protection for users and prolonging the service time of the optical elements. This paper presents durability test results for Be windows coated with atomic-layer-deposition alumina layers run at the European Synchrotron Radiation Facility. Expositions were performed under monochromatic, pink and white beams, establishing conditions that the samples could tolerate without radiation damage. X-ray treatment was implemented in various environments, i.e. vacuum, helium, nitrogen, argon and dry air at different pressures. Post-process analysis revealed their efficiency for monochromatic and pink beams.

Copper-Stabilized Si/Au Nanowhiskers for Advanced Nanoelectronic Applications

“…For that, 8 nm of alumina was deposited by the atomic layer deposition (ALD) method 34 onto the side facets of NWs without breaking the vacuum. 35 Chemical elemental distribution maps (Figure 4g,h) revealed that aluminum oxide had grown conformally onto the silicon surface, whereas no continuous Al 2 O 3 layer was formed on the gold droplet. Such area-selective deposition is typical for the chemical reactions used in ALD: a gold surface inhibits ALD growth as it lacks hydroxyl groups.…”

“…For a further enhancement of electronic component reliability, NW oxidation and current leakage along the side surface can be prevented by applying a dielectric layer. For that, 8 nm of alumina was deposited by the atomic layer deposition (ALD) method onto the side facets of NWs without breaking the vacuum . Chemical elemental distribution maps (Figure g,h) revealed that aluminum oxide had grown conformally onto the silicon surface, whereas no continuous Al 2 O 3 layer was formed on the gold droplet.…”

Impact of beryllium microstructure on the imaging and optical properties of X-ray refractive lenses

“…It is known that beryllium bonds very strongly with oxygen, and all oxygen in beryllium is in the form of beryllium oxide (beryllia, BeO). Therefore, this material is resistant to air corrosion due to its thin protective BeO film which can vary from 2 to 20 nm (Yurkevich et al, 2017). The concentration and the thickness of beryllia depend on the temperatures at which metallic Be is fabricated and processed (Papirov, 1969;Tomastik et al, 2005).…”