TiN coated aluminum electrodes for DC high voltage electron guns

Journal Article · Fri May 01 00:00:00 EDT 2015 · Journal of Vacuum Science and Technology A

DOI:https://doi.org/10.1116/1.4916574· OSTI ID:1190823

Mamun, Md Abdullah A. ^[1]; Elmustafa, Abdelmageed A. ^[1]; Taus, Rhys ^[2]; Forman, Eric ^[3]; Poelker, Matthew ^[3]

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1. Old Dominion Univ., Norfolk, VA (United States)
2. Loyola Marymount, Los Angeles, CA (United States)
3. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloy (Ti-6AI-4V). Following gas conditioning, each TiN-coated aluminum electrode reached -225 kV bias voltage while generating less than 100 pA of field emission (<10 pA) using a 40 mm cathode/anode gap, corresponding to field strength of 13.7 MV/m. Smaller gaps were studied to evaluate electrode performance at higher field strength with the best performing TiN-coated aluminum electrode reaching ~22.5 MV/m with field emission less than 100 pA. These results were comparable to those obtained from our best-performing electrodes manufactured from stainless steel, titanium alloy and niobium, as reported in references cited below. The TiN coating provided a very smooth surface and with mechanical properties of the coating (hardness and modulus) superior to those of stainless steel, titanium-alloy, and niobium electrodes. These features likely contributed to the improved high voltage performance of the TiN-coated aluminum electrodes.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC05-06OR23177
• OSTI ID: 1190823
• Report Number(s): JLAB-ACC-15-2090; DOE/OR/23177-3439; JVTAD6
• Journal Information: Journal of Vacuum Science and Technology A, Vol. 33, Issue 3; ISSN 0734-2101
• Publisher: American Vacuum Society
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
aluminum
field emission
cathodes
anodes
hardness