Design Optimization of the Plasma Ion Mass Spectrometer (PIMS) Designed for JET
The Plasma Ion Mass Spectrometer (PIMS) is the first device able of measuring the absolute flux of ions in each charge state present in the edge plasma of tokamaks. Ion-optical simulations with the ion-trajectory code SIMION 7 are carried out to improve the characteristics of this in-situ measuring device. Critical properties like mass resolution and transmission of the PIMS are calculated and optimized for a range of plasma parameters, i.e. different ion temperatures Ti and sheath voltages Vs. Also the influence of small magnetic field misalignments is investigated.