A novel position-sensitive ion-current detector array using a self-collection method for secondary-electron suppression

For the purpose of clarifying the spatial structures of plasma potentials and ion-current signals for plasma confinement studies in open-field plasma devices, multigridded electrostatic ion-energy spectrometers (IES) and compact-sized electrostatic ion-current detectors (ICD) are developed. These IES and ICD detectors are alternately placed in an array unit, and installed in the end region of the GAMMA 10. This position-sensitive ion-detector structure is proposed to obtain precise ion-energy spectra and absolute values of ion currents without any perturbations from simultaneously incident energetic electrons into the array. For employing this specific method, it is worth noting that no further additional magnetic systems except ambient open-ended magnetic fields are required for the proposed detector structure. This characteristic property provides a compactness of the total detector system and availability for its use in a plasma confinement device without disturbing plasma-confining magnetic fields. Availability of the detector is clearly demonstrated in the GAMMA10 plasma experiments.