Miniature Ion Gun to Explore Nanostructures in Tungsten

  • William Hastings

Student thesis: Doctoral Thesis

Abstract

Tungsten nanofuzz describes the nano scale structuring that can form under heavy He ion irradiation and high temperatures. While the underlying theory of nanofuzz formation and growth has been researched, a definitive answer for how the process works is yet to be discovered as it has never been produced under in-situ conditions, ie observed forming and growing in real time. A low energy, high flux He ion source was developed intended to be integrated with the MIAMI-2 system, Huddersfield, UK, for an in situ view of nanofuzz formation. The source was tested in an ex-situ chamber and performance compared to the existing MIAMI-2 ion beam line. The final design could sustain a 1 keV He beam at a flux of 1 × 1019ions/m2/s continuously and ran for over 50 hours without needing maintenance or cleaning. A heated sample holder was constructed to test if the rig was capable of producing W nanofuzz, however metal impurities in the heater system formed Mn nanostructures on the W surface at fluences in the order of 1 × 1023ions/m2, two orders of magnitude under that of nanofuzz formation. These structures are a novel phenomenon that require further investigation. Future improvements to the irradiation rig can be accomplished by refining the ion source for fitment to the MIAMI-2 system and exploring alternative heater designs to suppress impurity formation.
Date of Award1 Dec 2025
Original languageEnglish
SupervisorSimon Barrans (Main Supervisor)

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