Dramatic Reduction of DC Field Emission from Large Area Electrodes by Plasma-Source Ion Implantation
Field emission from the electrodes of practical electron guns is one of the principal phenomena limiting the operating voltage of these guns. There is substantial interest in developing photoemission cathode based DC electron guns operating with cathode field strengths and cathode-anode voltages well beyond the present state-of-the-art. These electron sources could provide high brightness, high average current beams for energy recovering superconducting linear accelerators, for applications in next generation light sources, electron cooling, and electron-ion colliders. We have studied the effect of plasma-source ion implantation on the field emission behavior of large area stainless steel electrodes. Our apparatus allows operation of disc-shaped electrode pairs with 100 cm{sup 2} uniform field areas to 125 kV. The cathode electrode is biased at high voltage, and the anode is electrically isolated, permitting measurement of the field emission current from the cathode. The electrode pairs were either mechanically polished, or implanted with nitrogen ions. Two separate ion implanted electrodes have shown negligible field emission at 20 MV/m, and emission between 0.5 and 1.7 pA/cm{sup 2} at 30 MV/m during multi-hour runs at high field. These electrodes showed very little conditioning effect.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 787354
- Report Number(s):
- JLAB-ACC-01-21; DOE/ER/40150-1913; TRN: US0109265
- Resource Relation:
- Journal Volume: 1; Conference: PAC 2001, Chicago, IL (US), 06/18/2001--06/22/2001; Other Information: PBD: 1 Jun 2001
- Country of Publication:
- United States
- Language:
- English
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