2011 Particle Accelerator Conference - List of Authors (Covert, S.)

Paper	Title	Page
WEP287	Field Emission Measurements from Niobium Electrodes	2020
	M. BastaniNejad Old Dominion University, Norfolk, Virginia, USA P.A. Adderley, J. Clark, S. Covert, J. Hansknecht, C. Hernandez-Garcia, R.R. Mammei, M. Poelker JLAB, Newport News, Virginia, USA
	Increasing the operating voltage of a DC high voltage photogun serves to minimize space charge induced emittance growth and thereby preserve electron beam brightness, however, field emission from the photogun cathode electrode can pose significant problems: constant low level field emission degrades vacuum via electron stimulated desorption which in turn reduces photocathode yield through chemical poisoning and/or ion bombardment and high levels of field emission can damage the ceramic insulator. Niobium electrodes (single crystal, large grain and fine grain) were characterized using a DC high voltage field emission test stand at maximum voltage -225kV and electric field gradient > 10MV/m. Niobium electrodes appear to be superior to diamond-paste polished stainless steel electrodes.

Paper

Title

Page

Field Emission Measurements from Niobium Electrodes

2020

M. BastaniNejad
Old Dominion University, Norfolk, Virginia, USA
P.A. Adderley, J. Clark, S. Covert, J. Hansknecht, C. Hernandez-Garcia, R.R. Mammei, M. Poelker
JLAB, Newport News, Virginia, USA

Increasing the operating voltage of a DC high voltage photogun serves to minimize space charge induced emittance growth and thereby preserve electron beam brightness, however, field emission from the photogun cathode electrode can pose significant problems: constant low level field emission degrades vacuum via electron stimulated desorption which in turn reduces photocathode yield through chemical poisoning and/or ion bombardment and high levels of field emission can damage the ceramic insulator. Niobium electrodes (single crystal, large grain and fine grain) were characterized using a DC high voltage field emission test stand at maximum voltage -225kV and electric field gradient > 10MV/m. Niobium electrodes appear to be superior to diamond-paste polished stainless steel electrodes.