E parallel to B energy analyzer for measurement of end-loss ions from the Mirror Fusion Test Facility-B

Abstract

An instrument is being designed and constructed to measure the mass and energy spectrum of ions lost from the end cells of the Mirror Fusion Test Facility (MFTF-B) experiment. The mass and energy analyzer is of an E parallel to B type and is being designed to resolve protons and deuterons in an energy range of 2–200 keV to within ±2% or 200 eV. The magnet is designed to be small and high field (1.2 T) so that it will fit into a radial array on the MFTF-B end dome. To achieve this large energy range in a small magnet, careful attention is paid to the trimming of the poles and electrode near the input edge. The input slit size is adjusted by fast variable apertures to increase the dynamic range. Also, the electronics is designed to be compatible with the high neutron flux rate in the MFTF-B environment. Detailed calculations on particle trajectories and magnet trimming will be presented, as well as detector and electronics design.