Comparison of the IOFFE neutral particle analyser with the Princeton analyser on the Mega Amp Spherical Tokamak

Abstract Charge exchange-neutral particle analysis (CX-NPA) will be applied for determining the ion temperature in the stellarator Wendelstein 7-X (W7-X), which is under construction, now, at the Max-Planck-Institute of Plasma Physics, Greifswald, Germany. Three ACORD-type analyser and one compact analyser (CNPA) are foreseen for the active NPA diagnostics at W7-X, i.e. NPA in combination with a 60 keV neutral beam injector, thus enabling locally resolved CX-NPA measurements. For an intermediate period the CNPA is now installed on the Mega Amp Spherical Tokamak (MAST) in Culham Science Centre, UK. The arrangement of the CNPA on MAST and results of energy spectra of plasma ions in MAST are presented. They are in a good agreement with measurements by the Princeton particle analyser.