WG1009
JLAB, Newport News, Virginia, USA
The Jefferson Lab IR/VUV FEL operates with a 325kV DC Photoemission electron gun based on GaAs photocathodes. Since 2008 the electron gun has delivered 325keV beam for FEL operations. More recently in February 2011, a copy of the FEL gun was tested in the Gun Test Stand with a bulk resistivity insulator from WESGO/Morgan. Despite being able to achieve 500kV for 8 hours under partial pressure of Krypton, the gun could not hold voltage under nominal vacuum conditions beyond 440kV, at which voltage the insulator suffered a massive puncture. Observations and results on field emission processing techniques using Krypton gas and insulator performance will be presented.
