Plasma Measurements of the Nonambipolar Electron Driven Ion Source
Abstract
A team at Oak Ridge National Laboratory has developed a new ion source for use in Electromagnetic Isotope Separation (EMIS). The Nonambipolar Electron Driven Ion Source (NEDIS) uses an inductively coupled 13.56 MHz RF plasma as an electron gun for electron impact ionization in a separate ion source plasma. This ion source and EMIS system has successfully produced, transported, and focused a 93 mA Argon ion beam. The plasma characteristics of the ion source plasma were determined with single and double-tip Langmuir probes as well as optical emission spectroscopy over a wide range of operating conditions. Plasma density measurements using a single-tip Langmuir probe were commonly observed above 1 x 1018 m-3 with total argon gas flow rates as low as 4.3 sccm and 13.56 MHz RF power as low as 550 W. Plasma density was measured above 5 x 1018 m-3 for several experiments. The measured current draw of the electron gun was typically above 10 A, with the maximum current draw limited by the power supplies at 22 A. The electron beam is columnated through the ion source plasma chamber and a steep gradient in plasma density and electron temperature has been measured as a function of radial distance from the electron beam. A general overview of the NEDIS along with additional results with argon will be presented.
U.S. Department of Energy - Office of Science, Nuclear Physics, Isotope Development and Production for Research and Applications.- Publication:
-
APS Annual Gaseous Electronics Meeting Abstracts
- Pub Date:
- 2018
- Bibcode:
- 2018APS..GECFT2002E