The design of a 400 kV parallel plate electrostatic analyzer for use with the 2 MeV heavy ion beam probe

Abstract

A parallel-plate electrostatic energy analyzer is being designed for use with a 2-MeV heavy ion beam probe. The electrostatic analyzer will be capable of measuring Tl/sup 2+/ ions of energies up to 2 MeV. Design goals are an accuracy of +or-40 V for potential profile measurements and +or-3 V r.m.s. for potential fluctuations. The design is based on a scaled-up version (by a factor of four) of the analyzer currently being used on the 500-keV beam probe on the Texas Experimental Tokamak (TEXT). An anticipated problem associated with the scale-up is that the analyzer top plate voltage will be 350-400 kV (four times the present analyzer voltage). Greater care must be taken to reduce the likelihood of arcing by the electric field. Computer simulations of the analyzer's electric fields and equipotential surfaces are being carried out to optimize the design and limit the possibility of field breakdown within the analyzer and between the analyzer and vacuum chamber wall. Models of the current TEXT beam probe analyzer are also being constructed for comparison.<>