1-MeV electrostatic ion energy analyzer

Abstract

We describe a high-resolution 90-degree cylindrical electrostatic energy analyzer for 1-MeV (singly ionized) heavy ions for experiments in the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL). By adding a stripping cell, the energy reach of the analyzer can be extended to 2 MeV. This analyzer has high dispersion in a first-order focus with bipolar deflection- plate voltages in the range of plusmn50 kV. We present calculations of vacuum-field beam trajectories, space- charge effects, field errors, and a multipole corrector. The corrector consists of 12 rods arranged in a circle around the beam. Such a corrector has excellent properties as an electrostatic quadrupole, sextupole, or linear combination. The improved energy diagnostic will allow measurements of beam energy spread, such as caused by charge exchange or temperature anisotropy, and better understanding of experimental results in planned longitudinal beam studies. Examples for such experiments include investigations of a beam patching pulser to correct errors in the head and tail of the transported beam bunch, and energy errors derived from ripples in the injector voltage waveform.