3D-Printed Vacuum Parts Enhance Gas Control for Atomic Technologies

The pursuit of miniaturised quantum technologies demands innovative approaches to maintaining the ultra-high vacuum environments crucial for their operation. Conventional pumping systems often contribute significantly to the size and weight of portable devices, prompting researchers to explore alternative methods for gas management. Now, N. Cooper, D. Johnson, and colleagues, from the University of Nottingham and industry partners Torr Scientific Ltd and Metamorphic Additive Manufacturing Ltd, detail a novel technique utilising intricately patterned, three-dimensionally printed surfaces to enhance gas pumping rates. Their work, published under the title ‘Exploiting complex 3D-printed surface structures for portable quantum technologies’, demonstrates a 3.8-fold increase in pumping speed achieved through the application of a non-evaporable getter coating to these patterned surfaces, offering a pathway towards lighter, more compact, and passively-pumped quantum devices. The team’s modelling suggests the potential for even greater improvements, with predicted ten-fold increases achievable through optimised surface designs.

Engineered surfaces markedly enhance gas removal in vacuum systems, a development validated by research demonstrating that three-dimensional printed structures, when coated with a non-evaporable getter (NEG), exhibit substantially improved pumping performance compared to flat surfaces. Quantitative analysis reveals a 3.8-fold increase in pumping speed, directly addressing the need for more efficient and compact vacuum systems in portable technologies such as atom interferometers and atomic clocks.

The methodology centres on the fabrication of intricate surface patterns using additive manufacturing techniques, enabling precise control over surface topography and maximising gas capture efficiency. The pumping rate coefficient, denoted as γ_i,s, quantifies the rate at which a specific gas species (i) is pumped away by a surface (s), and calculations account for both the flat and structured areas of each sample. Normalising performance in this way facilitates a comprehensive assessment of the enhancement achieved through patterned surfaces.

Researchers meticulously measured outgassing rates from both flat and structured samples coated with the NEG material. Outgassing refers to the release of gases adsorbed within or emanating from materials, a critical factor in maintaining high vacuum. The structured samples exhibit outgassing rates comparable to, or lower than, a 6 mm thick stainless steel baseline (1.1 x 10^-12 mbar L s^-1 cm^-2). Specifically, flat samples of 1 mm, 3 mm, and 6 mm thickness demonstrate outgassing rates of 3.6 x 10^-13, 1.8 x 10^-13, and 1.1 x 10^-13 mbar L s^-1 cm^-2, respectively, indicating that the additive manufacturing process does not introduce significant additional gas load into the system.

Researchers acknowledge the influence of boundary effects on the observed pumping rates and detail methods for scaling measurements to account for the finite size of the structured surface, ensuring the accuracy and reliability of the results. These boundary effects arise because the gas molecules near the edges of the sample experience a different environment than those in the centre, potentially skewing the measurements.

Detailed simulations, employing wrapped boundary conditions to model the periodic nature of the patterned surfaces, closely align with the experimental findings, providing a robust theoretical framework for understanding the observed phenomena. Wrapped boundary conditions treat the edges of the simulated area as if they connect seamlessly, effectively creating an infinite periodic structure. These simulations accurately predict the observed pumping rates and provide insights into the underlying mechanisms responsible for the enhancement.

The research establishes three-dimensional printing as a versatile tool for tailoring vacuum component surfaces to optimise gas dynamics, offering a pathway to reduce the overall mass and complexity of vacuum systems, a critical advantage for portable applications. By integrating these patterned structures directly into additively manufactured components, scientists and engineers can achieve significant improvements in vacuum performance while minimising system size and weight. The defined lower and upper bounds on pumping rate enhancement provide a framework for future design optimisation, guiding the development of even more efficient and compact vacuum systems.

This work demonstrates a significant potential for improving the performance of vacuum systems in a wide range of applications, including space exploration, scientific instrumentation, and industrial processes. By leveraging the capabilities of additive manufacturing and advanced materials, researchers can create innovative vacuum components that are lighter, more efficient, and more reliable. The findings of this study pave the way for the development of next-generation vacuum technologies, enabling new scientific discoveries and technological advancements.