Miniature retarding grid ion energy analyzer
A retarding grid analyzer intended for use as a high-density ({approximately}10{sup 12}/cc) plasma diagnostic has been designed, built and tested. The analyzer`s external dimensions are 0.125 inch x0.125 inch x0.050 inch which are smaller than macroscopic plasma scale lengths, thus allowing it to be stalk mounted and moved throughout the plasma. The grids are 2000 line/inch nickel mesh so that the linear dimension of grid open area is less than the debye length for plasmas with 10 eV electrons and 10{sup 12}/cc densities. Successive grids are separated by 0.01 inch in order to avoid space charge effects between grids and thus allow unprecedented energy resolution. Also, because the linear dimension normal to the grid is small compared to the ion mean free path in high pressure (>100 mTorr) discharges, it can be used without the differential pumping required of larger GEA`s in such discharges. The analyzer has been tested on a plasma beam source (a modified ASTeX Compact ECR source) and on an ASTeX S1500ECR source, and has been used as an edge diagnostic on the VERSATOR tokamak at M.I.T. Ion energy distribution functions as narrow as 5 eV have been measured.
- OSTI ID:
- 127952
- Report Number(s):
- CONF-920376-; ISSN 0003-0503; TRN: 96:000390
- Journal Information:
- Bulletin of the American Physical Society, Vol. 37, Issue 9; Conference: Meeting of the American Physical Society, Indianapolis, IN (United States), 16-20 Mar 1992; Other Information: PBD: Dec 1992
- Country of Publication:
- United States
- Language:
- English
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