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Title: Effects of the Thickness of Niobium Surface Oxide Layers on Field Emission

Abstract

Field emission on the inner surfaces of niobium superconducting radio frequency cavities is still one of the major obstacles for reaching high accelerating gradients for SRF community. Our previous experimental results* seemed to imply that the threshold of field emission was related to the thickness of Nb surface oxide layers. In this contribution, a more detailed study on the influences of the surface oxide layers on the field emission on Nb surfaces will be reported. By anodization technique, the thickness of the surface pentoxide layer was artificially fabricated from 3 nm up to 460 nm. A home-made scanning field emission microscope was employed to perform the scans on the surfaces. Emitters were characterized using a scanning electron microscope together with an energy dispersive x-ray analyzer. The SFEM experimental results were analyzed in terms of surface morphology and oxide thickness of Nb samples and chemical composition and geographic shape of the emitters. A model based on the classic electromagnetic theory was developed trying to understand the experimental results. Possibly implications for Nb SRF cavity applications from this study will be discussed.

Authors:
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1029367
Report Number(s):
JLAB-ACC-11-1439; DOE/OR/23177-1914
TRN: US1105765
DOE Contract Number:  
AC05-06OR23177
Resource Type:
Conference
Resource Relation:
Conference: IPAC2011, 4-9 Sep 2011, San Sebastian, Spain
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ANODIZATION; CAVITIES; CHEMICAL COMPOSITION; ELECTRON MICROSCOPES; FIELD EMISSION; MICROSCOPES; MORPHOLOGY; NIOBIUM; OXIDES; SHAPE; THICKNESS

Citation Formats

A.T. Wu, S. Jin, J.D. Mammosser, R.A. Rimmer, X.Y. Lu, K. Zhao. Effects of the Thickness of Niobium Surface Oxide Layers on Field Emission. United States: N. p., 2011. Web.
A.T. Wu, S. Jin, J.D. Mammosser, R.A. Rimmer, X.Y. Lu, K. Zhao. Effects of the Thickness of Niobium Surface Oxide Layers on Field Emission. United States.
A.T. Wu, S. Jin, J.D. Mammosser, R.A. Rimmer, X.Y. Lu, K. Zhao. 2011. "Effects of the Thickness of Niobium Surface Oxide Layers on Field Emission". United States. https://www.osti.gov/servlets/purl/1029367.
@article{osti_1029367,
title = {Effects of the Thickness of Niobium Surface Oxide Layers on Field Emission},
author = {A.T. Wu, S. Jin, J.D. Mammosser, R.A. Rimmer, X.Y. Lu, K. Zhao},
abstractNote = {Field emission on the inner surfaces of niobium superconducting radio frequency cavities is still one of the major obstacles for reaching high accelerating gradients for SRF community. Our previous experimental results* seemed to imply that the threshold of field emission was related to the thickness of Nb surface oxide layers. In this contribution, a more detailed study on the influences of the surface oxide layers on the field emission on Nb surfaces will be reported. By anodization technique, the thickness of the surface pentoxide layer was artificially fabricated from 3 nm up to 460 nm. A home-made scanning field emission microscope was employed to perform the scans on the surfaces. Emitters were characterized using a scanning electron microscope together with an energy dispersive x-ray analyzer. The SFEM experimental results were analyzed in terms of surface morphology and oxide thickness of Nb samples and chemical composition and geographic shape of the emitters. A model based on the classic electromagnetic theory was developed trying to understand the experimental results. Possibly implications for Nb SRF cavity applications from this study will be discussed.},
doi = {},
url = {https://www.osti.gov/biblio/1029367}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2011},
month = {Thu Sep 01 00:00:00 EDT 2011}
}

Conference:
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