Minimising Interference in Low-Pressure Supersonic Beam Sources
Abstract
Free-jet atomic, cluster and molecular sources are typically used to produce beams of low-energy, neutral particles and find application in a wide array of technologies, from neutral atom microscopes to instruments for surface processing. We present a simple analytical theory that is applicable to many of these sources, when (i) the nozzle-skimmer distance is such that free molecular flow is achieved and (ii) there is negligible interference within the skimmer itself. The utility of the model is demonstrated by comparing experimental data with calculations performed using the theory. In particular, we show that skimmer interference is negligible compared to attenuation by 'background' gas for room-temperature beams. Our treatment does not depend on any free parameters and obviates the complexity of previous theories. As a result, we are able to devise a number of design recommendations to minimize interference in sources operating with cryogenic-temperature beams.
Keywords
Cite
@article{arxiv.2409.12628,
title = {Minimising Interference in Low-Pressure Supersonic Beam Sources},
author = {Jack Kelsall and Aleksandar Radic and John Ellis and David J. Ward and Andrew Jardine},
journal= {arXiv preprint arXiv:2409.12628},
year = {2025}
}
Comments
18 pages, 16 figures. Accepted at the Journal of Chemical Physics